Module 1 – Nature of...

1 The authors would like to acknowledge support from the National Science Foundation through CIAN NSF ERC under grant EEC-0812072

Module 1 ndash Nature of Light

Matt Swanson Science Teacher Amphitheater Middle School Matt Swanson is an 8th grade science teacher in Tucson AZ where he was born and raised He enjoys wearing sunglasses almost as much as he enjoys learning about the natural world He holds a BA in Philosophy and Environmental Science and a MEd both from the University of Arizona Email SwansonMflowingwellsk12azus

Introduction to Optics Welcome to the study of optics more officially called optical science Optics is basically the study of light but donrsquot be fooled there is a lot of detail that is important for you to know First an informal survey is necessary to understand who you are and what you already know about optical science Donrsquot worry this is not a quiz

Figure 11 Summer optics program participants at Columbia University Courtesy of Ref 1


Question 1a None of these devices would exist without an understanding of optics Cell phones are able to send signals through empty space due to the technology developed through the application of optics Cameras would not be able to focus on the subject of a photo computers would not be able to send data through a network to bring you the internet and the television would not exist without the powerful knowledge contained within the field of optics Even though these devices work in complicated ways they exist because of the principles that you can learn about right in this ldquosuper-courserdquo Yes really You can learn about the principles that have allowed many highly paid engineers and scientists to create things like lasers cell phones and computers If you can learn the basic principles behind making these devices you could choose to join those who are creating the next generation of technological advances such as supercomputers improved lasers and invisibility suits If nature and the environment interest you know that knowledge of the electromagnetic spectrum has been essential to understanding the current climate of the earth including the problem of global climate change and its solutions


Question 1b What do you think optics is

a) The study of light

b) The study of nature

c) The study of visual arts

While answer a) is the simplest definition of optical science optics also studies nature in great detail and in fun ways For instance did you know that many animals have eyes that see different types of light than we humans can see Optical science can explain and help you create many optical illusions or help you understand what makes a painting worth millions of dollars Even though optics is concerned with light an understanding of optics can lead to many different areas of study pretty much any other subject you can think of

Question 1c Since there are so many different careers and ways of using your knowledge of optics whatever your own personal style of learning and doing things is you will benefit from your knowledge of optics Do you like teamwork Like in sports where everyone works together to accomplish a goal like winning a soccer game In optical science you can work with a team of people all of whom work together to accomplish a goal


Do you like to create Anyone who loves music or the arts can benefit from knowing how to make something look cool like a cutting edge artist or even how to trick the eye through illusions like a magician Are you the type of person who enjoys thinking about a really deep idea for a long time The sciences are full of questions like this that are far from solved What makes some surfaces reflect and others not How fast does light really travel What fundamental particles make up the energy we see around us You will learn some clear mathematical answers to these questions but that should not take away the sense of wonder about the natural world around us and the big picture of reality On the contrary understanding more about the everyday phenomenon happening all around you at any given moment can really help one appreciate and value the world around us especially if you are a deep thinker type of person Whatever your strengths and personality type this course is geared towards helping you learn how you can make optical science work for your own personality

11 What is Optics The answer to this question begins with another question What is Light This question has been an important question to many different people for most of human history You know by instinct what light looks like or at least when you are in a dark room you know that there is no light to allow you to see For many ancient cultures light came from the sun and the sun itself was worshipped as the giver of life Many cultures had gods and goddesses that represented the sun or light

Figure 12 A photograph taken by the author of a solar powered ventilator for a hostel restroom in Dublin Ireland


Figure 13 Amaterasu the sun goddess in ancient Japanese culture Artist 三代豊国歌川国貞(Utagawa Toyokuni IIIKunisada) 1857 From Ref 3

The study of light was of great importance to many medieval scholars and scientists Light was a very important subject to many of the Greek philosophers that created the way of thinking that we call modern science ldquoAbout light I am in the darkrdquo ndash Benjamin Franklin For all cultures around the world light continues to create profound questions about the world around us For example if the sun is the source of all light why can we make fires when it is nighttime Why do some deep ocean fish produce their own light Even up until the last century no one really had a good idea of the answers to these questions For a long time scientists had a hard time discovering what light actually does You will learn about how people figured out many of lightrsquos properties but first we should take a look at how we see light as human beings

Amaterasu is the name given to the sun goddess in ancient Japanese culture She was born from the left eye of another god Izanagi and her presence as the sun was celebrated as giving life to the world Amaterasu is claimed as the original ancestor of the Japanese royal family [2]

Many ancients have strong sun figures in their mythology See what you can find


The Eye Obviously as humans we detect light through our eyes which take in light that exists around us and processes it into a picture of what is going on around us

When light shining off of a tree is detected by our eyes the pupil controls how much light comes into the eye This light is then refracted by the lens of the eye onto the back of our retina in order to be converted into a chemical signal that is relayed through the optic nerve to our brain telling us that what we see is a tree (Figs 15 and 16) But animals are different insects and other animals can see light that humans cannot In fact only a small percentage of the total light that occurs all around us can be seen by humans what we see is only a small part of the light that exists all

Figure 15 A cartoon showing how an image of a dog is formed Adapted from Ref 5

Figure 14 The Egyptian Sun god Ra with the head of a falcon a bird that has exceptional vision From Ref 4


around us Optics is concerned with many types of energy not just the light that is visible to humans Infrared Goggles Otherwise known as night vision goggles these specially designed vision modifiers are built to detect infrared wavelengths which are light waves that are have longer wavelengths than what we see in the visible spectrum Infrared goggles detect the different light that is produced by heat so a warm bodied human shows up as a brighter color than the colder air around them

Figure 16 An illustration of the human eye Used with permission from Ref 6

These images demonstrate the difference between an infrared and a normal image Which cup is full How can you tell

Figure 17 (a) A regular photograph of author holding cups and (b) an infrared photograph of author


Is Light like Music Optics is the study of light in all of its forms People who study optics can understand and explain what light does Optics is also concerned with building devices to detect and utilize light for many different uses [7] The whole scale of light that exists is kind of like a musical scale In a musical scale we have a certain number of notes in the scale but we only play one note at a time when playing the scale

So if all of the spectrum of light were a scale the visible light that we would see would be just one note on the scale

Look at how much light is out there that we humans canrsquot see with our eyes Yet we can ldquoseerdquo with devices that detect other forms of light and we can feel the effects of these other forms of light

Figure 18 Musical notes showing the C major scale

Figure 19 A diagram of the electromagnetic spectrum showing the narrow range of visible light Adapted from Ref 8


Who Studies Optics and What Do They Do People who study optics include

Optical scientists Artists Astronomers Doctors (especially optometrists) Engineers Veterinarians Sports trainers Chemists Photographers Special effects editors Computer game producers Movie directors Cinematographers Meteorologists

Many many other types of jobs need people who understand light and how it works ACTIVITY 11 a Please click on your top five most interesting jobs from the list above Rank your top five jobs in order from your most favorite (1) to your least favorite (5)


Professional Photographer Photography is the use of cameras and other devices to capture and record images The existence of the camera is due to principles of optics that allow lenses and light to be focused for the best effect A cinematographer applies many of the same principles but to motion pictures as opposed to still pictures

Optical Engineer Optical engineers design the technology that is used in any device related to light Out of the following list which item do you think optical engineers helped design Lenses microscopes telescopes lasers high-speed internet toasters cell phones video game systems computers and solar panels Answer All of the above were designed by optical engineers except maybe the toaster By the way the average salary of an optical engineer is currently around $90000 a year Visual Effects artist Graphic designer Visual artists work in all kinds of settings and can use many artistic and creative skills in their work Visual designers use the principles of optics to select and create images that will be seen by many people An understanding of optics is needed for visual artists to ldquocatch your eyerdquo and communicate with their audience Doctors and Nurses Lasers and other complex optical devices are frequently used in medicine Many delicate surgeries that used to be risky and intensive are now done with ease thanks to

Figure 111 An eye catching photo taken by the author

Figure 110 A single lens reflex camera From Ref 9


many hardworking engineers scientists and medical professionals who are trying to protect the health of society If it is your dream to help others in the medical field you WILL be using optical technology at many levels during your workday Many of the most sought after and well-paid careers in the world use optical science If you know more about optics then you could be one of the people working in these fields

12 Cool Optics Technology

Since optics is a very large area of study there are tons of gadgets and things related to the study of light Lasers Lasers are super-concentrated beams of light that have a huge amount of energy in them Lasers first came out in the 1960s and have become part of everyday life in thousands of different ways Lasers have created a revolution in the ways that medicine is conducted Lasers can make delicate eye repair possible and can even create the possibility of bloodless surgeries by replacing scalpels in some surgical operations

Lasers can be used to make many things by having powerful lasers actually cut out metal for cars or computer chips Lasers are the technology that created CD and DVD players printers and that little barcode scanner in the supermarket that beeps when it reads the code on your groceries

Figure 113 Cartoon of laser surgery on the eye Adapted from Ref 11

Figure 112 Laser light through an optical device From Ref 10


Optical Illusions As you learn more about optics you will be able to explain for yourself the principles behind what you see However not yet knowing any of the science behind these illusions does not mean that you canrsquot enjoy them

1) Hermann Grid example Stare at this grid Do you see white dots at the intersection of the white lines These dots were not drawn in the grid Why do you think you still see what you know is not there The principles of optics are being used to trick your eyes

Figure 114 Grid Illusion From Ref 12


2) Perception illusion Do you see an old woman or a young woman in this picture

These types of illusions depend upon your brain selecting the image it wants to see There are two images but no right answer both images are drawn into the picture

3) Mirages A mirage is a famous natural illusion Under the right conditions such as a hot day with clear skies the light coming from the sun reflects off of the heated air that is rising off of the ground creating the famous water illusion

Figure 115 Drawing of an old woman or a young girl From Ref 13

Figure 116 Photograph of a desert mirage taken by Mila Zinkova in Primm Nevada on April 4 2007


4) 3-D technology creates the illusion that an object on a screen is three dimensional If you are old-school you might remember the blue and red glasses you needed to wear to see things in 3-D Todayrsquos optics technology with advanced 3-D glasses has made 3-D a popular high tech option Have you seen any 3-D movies lately

As you can see there are many awesome effects of optics in your day to day life as well as some cool ways in which people use optics in their lives Here is a final check to make sure you have understood the main ideas of this section of the course Assessment Question 12 a Which of the following occupations do you think are the most directly related to optics Pick the top five Optical scientists artists astronomers doctors especially optometrists engineers veterinarians sports trainers chemists photographers special effects editors computer game producers movie directors cinematographers meteorologists Question 12 b

Vocabulary for Day 1 optics optical engineer optician laser infrared visible light optical illusions pupil retina optic nerve


13 The Basics of Light Welcome back In this lesson you will learn the basic idea of how light works To understand light we will have to take a trip back in time to revisit some key scientists and experiments that have brought the study of light to where it is today The Eye First of all think back to our previous introduction to light Light that is reflected off of objects enters our eye and is projected onto the retina which then takes this image and converts it into a chemical signal that is sent to the brain Our eye adjusts to the amount of light in our environment much like a camera aperture with our pupils getting smaller when there is a lot of light and growing bigger to allow more light into the eye when we are in a dark place

Have you ever been blinded when you stepped outside of a dark room Your eyes were overloaded and it probably took a moment to adjust to the outdoors

Figure 117 Illustration of a human eye Used with permission From Ref 6


Question 13 a Out of the following two pictures which one represents someone who is in a darker environment Click on the picture that you think shows the eye in the darker environment

However accurate our vision is the fact that you have experienced temporary blindness shows that eyes can be overwhelmed with too much light

Figure 118 Illustration of a human eyes with constricted and dilated pupils


Question 13 b Human beings see many different forms of color but all of these colors fall into a category called visible light The spectrum of light is also referred to as ROY G BIV This name comes from the first letter of the main colors of the visible spectrum red orange yellow green blue indigo and violet


Question 13 c Which spectrum represents the seven main colors in visible light

The visible light spectrum can be seen in nature as a rainbow When we see a color in an object we are actually seeing the wavelength color that the object is not absorbing and instead reflects back at us Are you confused yet Donrsquot worry there are some very important details about what light is that we need to look into

Figure 119 Different types of spectra


Discovering What Light IS Eliminate the obvious Since you are learning about what light is it is important to go back to your own experience and figure out what light is NOT Itrsquos kind of like when you have NO idea what the answer to a multiple choice question is you eliminate the answers that you know are false Question 13 d

Obviously light is not a banana so you could eliminate (d) Also you know that we see things because of light so option (b) can be eliminated as well Try These Mini-Experiments So let us apply the same thinking to light what is light NOT Please try these simple experiments to prove to yourself what light is NOT

1) Light is not an object Find some sunlight or lamp light and try to feel it and touch it Your hand may react to the warmth of the heat but you cannot grab and hold light like you can grab and hold onto a book Therefore light is not an object so it appears that light does not weigh anything

2) Light does not behave like sound waves Think back to the last time you saw a thunderstorm When you saw that flash of lightning the light from the flash was visible


instantly but wasnrsquot there a delay in hearing the thunderclap from the lightning This is because sound travels much slower than light Now rub your hands together rapidly for a minute and then touch something Repeat this until you can see the electricity Is this light

3) Now try this thought experiment If you are outside of a room where other people are inside talking loudly can you hear them before you even open the door Yes unless you are in a sound-proof room like in a music recording studio The sound waves of people talking inside a room bend around the door to allow you to hear some sound but unless there is a gap in the door light cannot bend around a door Think of it this way if someone was in a house without windows you would not know if a light was turned on in the house but if they started playing Jimi Hendrix on their sound system at full volume you would know Sound waves bounce off of objects and that is how bats who are blind find food

4) Static test Light is NOT electricity but the two are related Have you ever given a static shock to somebody when you touched them A static shock can happen when you rub your feet on the carpet which causes a charge to build up when you touch your friend the built up charge releases resulting in a static electricity shock Like with lightning there is often light but you can feel an electric shock without light When light shines from a light bulb electricity is making that light but electricity is not the same thing as light either

Many of the same observations that you have just made have been made over the centuries by diverse groups of people trying to discover what light IS From a scientific point of view there have been two major ways of classifying how we think about light We will look at these two different ways of thinking and discover what they tell us

Figure 120 A bat sensing sound waves From Ref 15


14 Is light a wave

Over the years great thinkers investigated two ways of looking at light both of which lead to very interesting discoveries about the nature of light Light as a wave It has been known for a long time that sound travels in waves Many other things in nature work as waves too An ocean wave is a great example of a type of wave that can be seen in nature The idea that many natural events occur in waves is an ancient one and related to the idea that things in nature come in cycles The idea of cycles is as old as humankind Think of the seasons of the year most of the heat comes in the summer and is followed by a cooling of temperatures in the fall Temperatures gradually decrease in the winter when temperatures get very cold and then temperatures begin to increase again as spring arrives And the cycle goes on Try it yourself 1 With a friend take a section of rope 6 feet or longer a longer rope works better Each partner takes an end of the rope Now stand facing each other and walk away from each other until the rope has a little slack Choose a person to go first Move the end of the rope up and down and observe what happens to the rest of the rope Experiment with what happens when you increase the speed and force that you are moving the end of the rope with You have created waves

Figure 121 A large ocean wave From Ref 16


Scientists have observed and found out ways to predict the behavior of many different types of light waves Natural scientists can use the understanding of how waves work to predict the tides weather events and the effects of tidal waves and hurricanes Engineers and scientists have used knowledge of the wave behavior of magnets and electricity to create the technology that gives electricity to cities and that powers cars In other words if it could be proven that light behaves like other waves found in nature then there are an incredible number of cool things that can be done to use light waves Light as a Particle Much of science and mathematics depends upon describing the behavior of movement of something such as a particle Another way to look at a particle is to imagine a dot in the middle of a blank page Once you add x and y axes to this page you can describe exactly where the dot is on the page If you wanted to find a particle in three dimensions you would need to add a z axis You could write a mathematical equation to describe a wave but you could not tell exactly where a wave is at any time

Figure 123 An 3-D illustration of a box with a point in the middle of the box

Figure 122 Illustration demonstrating how to make a wave using a rope


When you look up how to get somewhere you are a particle a single point on the earth To figure out where you are going all that is needed is to measure the distance between the point that represents you and the point that represents where you are going Scientists engineers mathematicians and anyone who plays video games uses the idea of particles all of the time It is an idea that is used so much that few people really think about it much anymore A particle is as predictable as it gets in mathematical models of 3-D space Question 14 a How far is your house from where you are right now

a) 2 miles or less

b) 5 miles or less

c) 10 miles or less

d) Greater than 10 miles away

Question 14 b How would you show the distance from right where you are sitting to your house if you were given a map Describing an object as a point in space has allowed rockets to go to the moon ships to get to their ports on time and for you to say exactly where you are at the moment If light can be described as a particle then we could predict where light would be at any given time much like we predict where particles of air pollution will show up in a city or where the sun is at any given time of the year The Debate over the Centuries Particle vs Wave

Many different scientists and thinkers have tried to prove that the behavior of light can be modeled as either a wave or a particle Below are the highlights of several important experiments Your job is to learn about these experiments and understand each famous argument At the end of this section you will have a chance to test your knowledge about the waveparticle debate Isaac Newton Way back in the day the 15th century to be more precise Isaac Newton did a simple experiment


Newton took white light and split it with a device known as a prism which splits white light into the different wavelengths of color Newton shone white light into the prism and using his prism reflected that light onto a surface the light that he split off was red light Newtonrsquos experiment demonstrated that white light is a mix of many colors The next thing Newton did was to try to split the red light again but no matter how many times he did this he only received red light as a reflection (Fig 126) Newton concluded that light behaved as particles that could be split off from each other

Christiaan Huygens Huygens was a famous Dutch mathematician inventor and writer whose experiments with light demonstrated that light can be modeled as a wave One famous experiment that led to a mathematical model was that of shining a light through a small opening

Experiment Review

1) White light is shone on a prism

2) Red light is reflected

3) Red light enters a second prism and red light comes out

4) Red light cannot be ldquobroken downrdquo into another color but white light can

Conclusion White light is a mix of all colors

Figure 126 Diagram showing Newtonrsquos attempt to split red light

Figure 124 Portrait of Sir Issac Newton From Ref 17 Figure 125 A cartoon of the type of prism used in Newtonrsquos experiment


called an aperture When someone shines a light on one side of a wall with a hole in it the light comes through the hole but then immediately spreads out in the next room

Huygens experiment seemed to show that light can be modeled as a wave because a particle would travel in a straight line and the light that you see in a key hole would not spread out beyond a straight line

Try it yourself 2 Take a cardboard box and poke a hole in the middle with a pencil Hold a flashlight inside the box and have someone sit at eye level with the hole you made Now turn off the lights in the room and at the same time turn on the flashlight Can you clearly see the light pass in a straight line out of the hole Hold up a piece of dark paper in front of the hole is the light a point on the paper or does it cover a large area of the paper Thomas Young was directly challenging Newtonrsquos idea of light as a particle when he came up with his two-slit experiment In this experiment an intense light (nowadays we could use a laser) is shone on a square with two slits or openings in it much like the experiment described

Figure1 27 Portrait of Christiaan Huygens From Ref18

Figure 128 Cartoon demonstrating that light can be modeled as having wave like behavior


earlier but this time we have two openings If light behaves as a particle and not a wave the light should shine straight through the two openings and create two points on the other side Instead of two points of light an interference pattern is created meaning that the light has wave-like properties Experiment with the animation below to see what happens Question 14 c What other things are wavelike

Figure 129 Portrait of Thomas Young From Ref 19


Albert Einstein weighed in on the debate in 1905 when he released a paper on the photoelectric effect which won him the Nobel Prize Basically Einstein described light as existing as points in space and time called photons that behave like particles Einstein predicted that other particles like electrons would be affected by these photons which has proved to be true over and over again

Let us solve this debate once and for all Activity To make sure that you understand the wave model and particle model argument you will place the picture of each scientist on the correct side of the chart You will then match the theoretical statement made by each one of these four scientists with their pictures

Figure 130 Picture of Albert Einstein From Ref 20


Is Light a Wave or a Particle Recently humanity has discovered the truth light is truly unique in that it has the properties of both a wave AND a particle It is these unique properties that we will look at next as we look at light in two ways as a wave and a particle

15 The Electromagnetic Spectrum

Question 15 a Which of these pictures below represents a wave

Vocabulary for Day 2 particle wave aperture prism photon photoelectric effect

Figure 131 (a) A cartoon of a radio tower (b) an ocean wave and (c) a diagram showing phase modulation


The answer is that all of these examples are forms of waves light is part of all of the waves that exist in nature The amount of visible light that we can see is only a tiny part of the total amount of electromagnetic energy that exists in waves Recall that Figure 19 shows the range of electromagnetic energy with its associated wavelengths and is called the electromagnetic spectrum Understanding the electromagnetic spectrum is essential to the understanding of light Visible Light Let us start with the visible spectrum what we humans can see with our eyes All of the colors you see represent only a tiny portion of the electromagnetic spectrum these waves are near the middle of the spectrum Visible light represents the tiniest portion of the spectrum

How the Electromagnetic Spectrum is Organized

The electromagnetic spectrum is organized by the size of the wave of energy it represents For instance the wavelengths in the visible spectrum are smaller than the size of some kinds of bacteria (how small is this) This means that one entire wave has a peak to peak size that is less than the size of some types of bacteria Most bacteria are so tiny that you cannot see them without a handy invention called a microscope Even though visible light waves are very small they are near the middle of the electromagnetic spectrum That means that the spectrum contains waves about the size of the nucleus of an atom 1 million times smaller than some types of bacteria On the other side of the spectrum we have the largest waves of energy which have amplitude that is larger than a skyscraper building

What is wavelength and amplitude Think back to the experiment yesterday where you and a partner each held the end of a rope (Try it yourself 1 Fig 122) When you gently shook the rope up and down the rope moved up a little but not much As you increased the speed at which you moved the rope the amplitude of the rope was higher the rope moved up and down more from its original location

Figure 132 Diagram showing the wavelength and amplitude of a wave


Waves Smaller than Visible Light

Ultraviolet wavelengths If you have ever seen a commercial for sunscreen or sunglasses you might have heard the term UV rays UV rays come from the sun and sunscreen protects your skin from harmful UV rays Ultraviolet waves are even used to kill bacteria in drinking water Have you ever seen a black light This is an ultraviolet lamp Ultraviolet light has a very interesting quality it can make certain colors and chemicals glow

Ultraviolet radiation and the Sun

The sun is the largest emitter of UV rays that cause sunburn and stimulate some forms of skin cancer On the other hand UV light also triggers a process in our bodies that creates vitamin D an important vitamin for health Basically UV light when it is too intense is not good for us but is necessary in the right amount Lucky for us 97-99 of UV rays are blocked by the layer of gas in the atmosphere called the ozone layer When exposed to the sun your skin responds to UV light by tanning which helps the skin absorb more UV rays and block their harmful effects

By learning about UV radiation humans have been able to not only protect human health but also construct multi-layer optical devices to filter and detect UV rays One such invention is the solar telescope (Fig 135)

Figure 133 Chemical glowing under an ultraviolet light From Ref 21

Figure 134 Scorpion under a black light From Ref 22


The solar telescope is a special telescope that filters out light to those wavelengths that are close to the visible spectrum Since solar telescopes are designed to observe the sun they do not collect light and focus it onto the viewing lens Many solar telescopes do the opposite and actually filter out light so that astronomers can observe the sun safely Because there is not as much need to capture light solar telescopes can be much smaller than regular telescopes

Figure 135 Image of a solar telescope With permission from Ref 23

X-Rays

Have you ever received a radiograph (this is the official term for having your picture taken by an X-ray machine) If you have ever been to the dentist or the doctor chances are that you have experienced this before An X-ray is actually a type of electromagnetic radiation that is used to take a picture of what is inside of something most likely a part of the body The wavelength of an X-ray is about the size of an atom

How do X-rays do that The smaller the wavelength of the wave the more likely it is to be able to pass through solid objects If you shine visible light on a solid object like a black box the light bounces off the object which is a good thing or else you couldnrsquot see the box X-rays however mostly pass through objects with only some of the X-rays bouncing back That is why an X-ray can be used to reveal the bones in


your hand as in Figure 136 X-rays are also used to see what a person is carrying in their pockets or luggage which is something you have experienced if you ever have gone through a security check at an airport

Gamma Rays

The smallest wavelength of the electromagnetic spectrum is the gamma ray which is less common in most peoplersquos day-to-day lives Gamma ray wavelengths are about the size of a nucleus of an atom which is many times smaller than a single human cell Gamma radiation comes mostly from radioactive materials like radium uranium and plutonium These elements are special because they have properties that allow them to release huge amounts of energy in the form of gamma radiation Such elements have been used in nuclear power as well as nuclear weapons Since the wavelength of gamma rays is so small it passes right through most solid objects unless these objects are extremely thick

Gamma Rays are dangerous

If you know any comic book history you know that the creation of the Incredible Hulk was the result of a blast of gamma radiation that scientist Bruce Banner was exposed to Although turning into the Hulk was obviously a lot of trouble for Bruce Banner in reality the effects of gamma radiation are much more serious and a lot less green and angry Exposure to gamma rays can cause severe damage to your internal organs as well as your skin because the short wavelengths of gamma radiation interfere with the cells in your body Radioactive materials have to be stored in thick containers sometimes buried deep underground just so those invisible rays donrsquot hurt living cells

Figure 136 The first X-ray Notice the ring on the finger X-rays were discovered by Wilhelm Roentgen in 1845 From Ref 24


Gamma Rays are Useful

Gamma rays are not just in atomic weapons Many of the properties that make gamma rays dangerous also make them very useful In fact there is a whole branch of medicine known as nuclear medicine and gamma rays are used in many other scientific applications as well To understand many of these uses for gamma rays it is important to remember that gamma rays are naturally occurring electromagnetic waves given off when the unstable radioactive nucleus of an atom decays or loses energy over time An atom with an unstable nucleus that decays is called a radioactive isotope also called a radioisotope Actually when unstable atomic nuclei decay they give off three types of rays alpha beta and gamma rays The alpha rays have a positive charge beta rays have a negative charge and gamma rays are neutral These rays especially the gamma rays have many useful applications that scientists have discovered over the years

One of the most important applications of gamma rays is in the field of nuclear medicine In general nuclear medicine combines radioactive isotopes with pharmaceuticals to more accurately map the progress of a disease throughout the body For instance a radioactive substance called a radiotracer or a radiopharmaceutical is used by doctors as a way to trace the passage of the radioactive substance through the bodyrsquos complex systems allowing doctors to diagnose any problems In this technique the radiotracer is put into the body of the patient and it emits gamma radiation that is detected by a special camera outside of the patientrsquos body called a gamma camera (Fig 137) This technique has been a key to detecting everything from organ dysfunction to bacterial infections

Figure 137 A patient being examined with a gamma camera From Ref 25


The Larger Wavelengths

Infrared light

On the other side of the visible light spectrum there are the electromagnetic waves that have wavelengths larger than visible light The first type of wavelength is infrared The wavelength of an infrared wave is a little bigger than the wavelengths of visible light To compare the infrared wavelength is about the size of the point of a pin Infrared light has a wavelength that some other creatures like insects can see When mosquitoes fly around their infrared vision allows them to find warm blooded animals to feed from Infrared radiation is related to heat so it has been used in many ways to detect heat and temperature patterns

Satellite weather imaging Using infrared sensors satellites can detect weather systems as they start to form helping to predict the weather and even save lives by detecting huge storms ahead of time

Infrared goggles Goggles that are designed to detect infrared wavelengths have been used for many purposes like by firefighters trying to find their way around a burning building rescue workers looking for body heat to rescue victims of an accident or police officers to determine the location of activity at a crime scene Many cameras now come equipped with infrared

Entertainment Have you ever used a remote device to turn something on or off before Look at the devices below and think about which ones you have used or seen before (clicker wireless mouse televisionstereo controls) Infrared technology is all over the place

Figure 138 Different types of devices that use infrared technology Images used with permission (a) from Ref 26 (b) from Ref 27 and (c) from Ref 28


Question 15 b

Which of the following pictures represent an infrared camera image Which picture represents X-rays UV light Match the correct answers to the pictures below

Microwaves

Despite the name microwaves are the second largest type of wavelength on the spectrum Although microwaves are bigger than other waves on the spectrum they are much smaller than radio waves Microwave wavelengths range in size from about the size of a monarch butterfly to larger than a baseball Microwaves are used in ways similar to radio waves but they can carry more information For instance cell phone towers receive and send out signals in the form of microwaves Probably the best example of microwaves used in everyday life is the microwaves that carry information to computers in wireless networks

The microwave The microwave oven became a common household item in the 1970-1980s The microwave oven does indeed use microwaves to cook food by passing the rays through food

Figure 139 Images of (a) the author (b) a hand and (c) a scorpion


The microwave became possible only after a large amount of these waves could be produced using a device inside each microwave called a magnetron

Are microwaves dangerous There have been some studies showing that microwave exposure can be harmful Microwave radiation has even been explored as a weapon Intense exposure to microwaves can cause objects or human tissue to heat up but it is thought that most people are not exposed to enough microwave radiation for damage to occur Maybe you can help solve this debate

Radio waves

The largest waves on the electromagnetic spectrum belong to radio waves Radio wavelengths stretch from the size of an average sized human up to the size of a skyscraper There are two major types of radio waves natural and man-made

Natural radio waves are produced by lightning storms and they are also produced by planets and other objects in deep space

Man-made radio waves are produced for the purpose of broadcasting radio and television stations Sound andor pictures are transferred into electrical signals that can be carried on a radio wave to your TV or stereo

Have you ever tried to find a new radio station by adjusting the dial on a radio Each station is a different frequency of radio waves That means that your favorite station is a very exact wavelength of radio waves


A Word About Frequencyhellipthe Opposite is True

Frequency is the measure of the amount of waves that pass a point in a specific unit of time For example if your favorite radio station is 913 the radio waves hit your antenna 913 times per second The electromagnetic spectrum has a rule for frequency the larger the wavelength the lower the frequency By the same rule the smaller the wavelength the higher the frequency Having knowledge of the concepts of wavelength and frequency is the key to understanding how many things work including radio stations TV computers and cell phones to name a few You will be learning how these devices work in another module of the super-course

Question 15 c What type of electromagnetic wave has the highest frequency Hint Which type of wave has the smallest wavelength

Here is a simple equation that is extremely useful in relating wavelengths and frequency


Frequency is an inverse relationship with wavelength

120640 =119959119943

Where

λ = Wavelength

v = Velocity of Propagation


The velocity of propagation is how fast a wave travels relative to the speed of light

Summary Optics studies all of the electromagnetic spectrum In optics the entire spectrum is studied That means if technology or nature involves any part of the spectrum it has to do with optical science

Assessment


Question 15 d

What speed approximately represents the speed of light

Question 15 e

What is the equation for the wavelength of a light wave related to velocity of propagation and frequency

Vocabulary for Day 3 Wavelength frequency velocity of propagation infrared x-ray microwave gamma ray ultraviolet light radiation hertz wireless networks magnetron


16 Light as a Particle In Section 15 we learned that the electromagnetic spectrum consists of various waves having different wavelengths and frequencies These waves include radio microwave infrared visible ultraviolet x-ray and gamma rays Question 16 a

Thinking of light as a wave is important but it is not the whole story Recall that the behavior of light can be modeled as a wave and as a particle (Section 15)

Light as a particle When you need to describe to someone where you are you think of yourself as a particle or a point This allows you to tell someone that you are at a specific spot as opposed to just anywhere When in optical science we need to predict where light will go we have to be exact about where the light is luckily light does not behave like just a wave but it behaves like a particle too

The Photon The photon is the basic unit of light Unlike an electron a photon doesnrsquot have mass or a charge The photon can interact with other matter a good example is the solar photovoltaic panel that converts sunlight into electricity These panels are becoming more and more common on rooftops across the world In fact there are lots of inventions and technology that were created using knowledge of this particle called the photon


You can think about photons as little particles that are zooming out from any source of light towards another point in 3-D space For example as you are reading this lesson on a computer screen billions of photons are coming into contact with your eyes as well as the rest of your body There are also photons from other light sources zooming all around you traveling at speeds near the speed of light in a vacuum If you are near a window or a skylight there are photons that have traveled about eight minutes and twenty seconds from the sun to where you are A Review of Really Small Things An atom is the basic building block of matter Atoms are too small to see but they consist of a nucleus of protons and neutrons This center has a cloud of orbiting electrons that are small negatively charged particles Electrons are really important because they determine how different atoms react with one another and produce the matter we see all around us

Starting around a century ago scientists found that light a form of energy is a subatomic particle that interacts with the electron Heinrich Hertz Max Planck Albert Einstein and the Photoelectric Effect If you look at the electromagnetic spectrum notice that the units of frequency are called Hertz (Hz) A Hertz is the number of waves per second of a specific electromagnetic wave This unit was named in honor of Heinrich Hertz who was the first person to observe the effect that light had on solid objects In 1887 Hertz observed that when electrodes a material that conducts electricity were exposed to ultraviolet light they produced electrical sparks Although he did not ldquodiscoverrdquo the photon Hertzrsquos observations during this experiment helped later scientists

Figure 141 Cartoon of an atom


discover the particle aspects of light The emission of electrons when light hits objects is called the photoelectric effect In 1900 a scientist named Max Planck created the theory that any kind of energy that was absorbed or given off could be measured in separate units called quanta Planck was not just talking about light but about energy in general His idea was hugely influential and he was awarded the Nobel Prize in 1918 In 1905 Albert Einstein finished a paper called On a Heuristic Viewpoint Concerning the Production and Transformation of Light In this paper with a very long title Einstein was able to explain the photoelectric effect that scientists had been observing for years He realized that light not only had the properties of a wave but that light was also made up of unique particles which Einstein called ldquolight quantardquo which were renamed photons When Einstein applied this theory of light to what scientists had been observing it explained the photoelectric effect and predicted that the number of electrons that were ejected from a material would increase with the frequency of the light This discovery has led to many inventions like the laser and the X-ray because now people could predict how light behaved with much more accuracy Einstein was awarded the Nobel Prize in 1921 for this discovery Even though photons are particles without mass or charge understanding them has been essential to huge discoveries that have changed the world

Technology Focus Solar Panel

When electrons are constantly jumping down a chain of atoms we have an electron flow otherwise known as electricity Most of our electricity comes from burning fuels which creates pollution that is bad for us and the rest of planet earth In a photovoltaic solar panel there are layers of semiconducting materials that are specially constructed to allow electrons to jump from the atom they orbit to another one next door On a sunny day photons hit the layer of the semiconducting material in the solar panel When the photons hit this special layer their energy is absorbed and it is enough to transfer some energy to the electrons in the panel and knock an electron off of one atom and onto another When you

Figure 142 Diagram showing the photoelectric

Photoelectric Effect When photons of sufficient energy hit the surface of a material the photons are absorbed causing electrons to be emitted


have millions of photons hitting the panel every second the energy in the photons is converted into a flow of electrons moving from atom to atom in the material in other words electricity is produced This process is known as the photovoltaic effect No burning of fuel is required for a solar panel to produce electricity

Quantum Theory

Question 16 b

Figure 143 Diagram showing how a photovoltaic panel works


Of course the regular ball would be easier to hit because it would be easier to predict the position of the ball Just like a tennis player who needs to be able to predict the position of the ball in order to hit it an optical scientist sometimes need to predict exactly where light will be in order to know how to create something uses light like cameras or computer networks This is why thinking about light as measurable points such as photons is so important After the quantum theory of light was shown to be useful many scientists inventors and engineers started to use the idea of the photon to predict exactly how light behaves in specific situations For instance if you were stranded on a desert island with nothing but a mirror at what angle should you hold the mirror to create the brightest reflection to signal for rescue What about a more practical problem like how to concentrate a light beam into a super-concentrated form a laser Many of these discoveries were possible through predicting lightrsquos behavior using the particle properties of light

Enrichment Quantum Electrodynamics Quantum electrodynamics besides having a fancy name is concerned with describing how light and matter interact One famous scientist named Richard Feynman was very good at explaining the basic rules of how light interacts with matter Feynman outlines three rules

1) A photon travels from one place to another in space and time

2) An electron goes from one place to another in space and time

3) An electron absorbs or emits (gives off) a photon at a specific place and time

Next there are three pictures that you can draw to show each of these three rules

Figure 144 Diagram illustrating the basic rules of how light interacts with matter From Ref 29


Notice how these pictures are set in a graph where space and time are the axes Using these three simple drawings a person can start to predict what light will do in a given situation Even though quantum electrodynamics can be very complicated the three basic rules stated here is the foundation for understanding how photons interact with anything in the world Question 16 c Draw a diagram to show a photon hitting an electron Remember to label your axes for time and space (distance) 17 The Speed of Light Question 17 a When you turn on a light in your house is there a time delay from when you flip the switch until you see the light

Figure 145 A cartoon pointing out that photons travel very fast


The speed of light is so fast that humans do not have fast enough reflexes to time light it looks like the light turns on instantly Light is made up of photons that also act in a wave form It is useful to know about photons but what about some other important properties of light that are related to this idea One of the most important discoveries has been the speed that light travels which is a physical constant The speed of light is a physical constant because in a vacuum light travels at a constant speed ALL electromagnetic radiation travels at the speed of light In a vacuum there is nothing else no particles no air nothing Space is almost a vacuum with only small little particles traveling in the space between large things like planets Earth is NOT a vacuum we have all kinds of particles in the air around us that get in the way of a traveling photon Al-Hazen Galileo For much of history curious people have wondered if light travels a path like ordinary objects or if it just appears instantly In 1021 an Islamic Philosopher named Al -Hazen used a device called a camera obscura to argue that light must travel a path like any other matter

A camera obscura is a device such as a box with a tiny pinhole on one side Light coming from an object that is outside of the box goes through the pinhole and forms an upside-down image of the object on the inside wall of the box If light just appeared somewhere then the light that went through the pinhole would not be upside down or smaller In his Book of Optics Al-Hazen concluded that light had to be traveling in a straight line from one point to another In many optical engineering applications today light is still explained as a ray that travels in a straight line until it interacts with a material

Figure 146 Diagram showing how a camera obscura works Adapted from Ref 30


Finding out how fast light traveled turned out to be a more difficult matter to determine Many early thinkers were unable to measure the speed of light with their experiments In 1638 Galileo tried to measure the speed of light by having a friend stand a measured distance away and timing how long it took to see the light from a lantern once it was uncovered

Remember Speed = DistanceTime

He was unable to get a time measurement for the same reasons you cannot time how long it takes for light to reach your eyes from a lamp when you flip the switch at home The only way to measure the speed of light is to observe things very far away from Earth How far away Not twenty kilometers 100000 km or even all the way around the earth We are talking about distances in the solar system

Planet in the Solar System Average Distance from Earth in Kilometers Mercury 91500000 Venus 42000000 Mars 75000000

Jupiter 630000000 Table 11 Average distances of Planets from Earth Calculated from ref httpcuriousastrocornelledu

Ole Romer and the Moons of Jupiter Building on the work of those who went before him Ole Romer a Danish astronomer calculated the speed of light based upon observing Jupiterrsquos moons In 1671 Romer along with other scientists made observations of hundreds of the eclipses of Jupiterrsquos moons Romer and the other scientists observed that times between eclipses got shorter as Earth approached Jupiter and longer as Earth moved farther away The only way to explain these observations was if light had to travel through space towards earth and took more time when Earth was farther away Because of the large distances involved Romer and his colleagues could finally measure the speed of light Romer himself never actually calculated the speed of light but his data was the basis of the calculations that Christiaan Huygens used to calculate the speed of light

Figure 147 Diagram from an article on Romerrsquos speed of light measurement Adapted from Ref 31


Romerrsquos diagram of the speed of light B is Jupiter which in this diagram is eclipsing a moon DC The Earth is moving away from Jupiter from point L to point K and the earth travels towards Jupiter from point F to point G You Figure out the Speed of Light Remember the speed of any object is Distance divide Time To calculate the speed of light one just has to know how far away an object is and how many minutes it takes to get to its destination Question 17 b


Question 17 c Light travels really fast For an idea of how fast light travels a light beam could travel 74 times around the entire earth at the equator in just one second Of course as you learn more about light you will understand how light behaves in different situations For example light travels faster in a vacuum than in Earthrsquos atmosphere and when light hits different materials it behaves in all kinds of interesting ways


Assessment Question 17 d How much time (in seconds) does it take for light to travel to Earth from the following planets Use the value 300000 kmsec for the approximate speed of light


Question 17 e


Question 17 f Discuss why scientists had a hard time measuring light for so many years

18 Optics Applications

Congratulations on what you have learned so far Up until now you have learned many of the basic facts about light the electromagnetic spectrum and the idea of light behaving as both a wave and a particle otherwise known as wave-particle duality In this section we will revisit some of the very cool ways in which this knowledge is used every day by people all over the world We will also look at how optics is on the cutting edge of future technology and look at some of the ideas that were once science fiction and that may soon be real Technology and Art Many times young people think of technology and science as having to do with computers lab coats and lots of math While math especially is very important to optical science do not be mistaken and think that more artistic or creative work does not involve all of the concepts you are learning about In fact the opposite is true Everything around you right now has three dimensions (3-D) length width and depth However a page or a movie screen even the computer screen you are looking at can only be two dimensions the screen or page has no depth Art and Animation Do you like to draw Any person who gets serious about art has to learn many optics techniques The first technique you might have already learned about is perspective how to make a 2-dimensional painting look 3-dimensional To draw something that looks real artists and animators have to carefully observe how the eye perceives objects For instance take a look at this photograph of railroad tracks (Fig 148) The tracks seem to vanish at a single point on the horizon although you know from experience that the tracks keep going To reproduce an image like this the artist has to use one-point perspective he or she has to make the drawing of the tracks disappear at a point to give the appearance that the tracks keep going and to trick the eye into believing that the image on flat paper is 3-D

Vocabulary for Day 4 Physical constant vacuum quantum electrodynamics photon atoms electrons orbit subatomic particle quantum


This is one of the most basic tricks for artists but perspective can get a lot more complicated Artists need to study the details of how we view visible light otherwise the audience cannot believe that what they are looking at is real Computer Animation and Video Games Artists in the computer game industry need to have many skills related to optical science In addition to the skills that animators and other artist need computer game designers also need to know about how light reacts with real objects A good computer game designer can use their knowledge about light to make objects in their game appear realistic so that the people who play the game are drawn into the world of the game Although many new computer and video game console games look extremely realistic there have been years of hard work by thousands of people to get real world objects like water to look good in a simulated 3-D world Which one of these computer animated water pictures looks more realistic to you Why

Figure 148 Perspective drawing of railroad tracks

Figure 149 Illustration or railroad tracks

Figure 150 (a) and (b) Computer simulated images of water


3-D Movie Technologies Have you ever seen a movie in 3-D A really cool application of optics comes in 3-D technology allowing 2-dimensional objects to appear 3-dimensional and pop out at you Old School 3-D Anaglyph images used to create a 3-D effect were developed by Wilhelm Rollmann in 1853 Back in the day meaning from Rollmanrsquos time until the end of the 20th century 3-D glasses consisted of one red lens and one blue lens (Fig 151) The image on the movie screen or in a book was ldquodoubled uprdquo In other words a red ink drawing and a blue version of the same drawing were superimposed on each other to create an illusion where one eye sees only the red image and the other eye sees the blue image Using principles of optics that you will learn in this super-course the resulting image appears to pop off of the page into 3-D space

Notice how the anaglyph image looks blurry in this old 3-D comic book (Fig 152) if you had glasses the image would transform into something that appeared to pop out at you

Figure 151 A picture of ldquoOld Schoolrdquo 3-D glasses

Figure 152 USDS 3-D image with superimposed colors From Ref 32


Current 3-D movie technology There is a good chance that you have seen a 3-D movie in the past few years the 3-D image has grown in popularity thanks to technology that was created due to a better understanding of optics In current 3-D technology there is no need for different colored lenses Instead each lens of the 3-D glasses transmits different polarized light to your eyes You will be learning more about polarization but basically what this means is that the different polarizing filters are made to accept different directions of light In modern 3-D movie theaters two projectors run at the same time with two slightly different images on them With your glasses on these images trick your eye into thinking they have depth thus the image seems to pop out towards you on the screen

Future Technology Many things that seemed like science fiction in the past are now becoming common in many peoplersquos lives For instance cell phones are now very common and many devices do not have any wires People who are old enough to have grown up without cell phones and the internet anybody who is more than 18 years old counts are amazed at how fast technology has advanced In this section you will get a brief preview of some of the technology being developed using optics and that may actually appear in your lifetime Quantum Computers Computer technology has developed rapidly in the past five decades but many computer engineers are realizing that there is a limit to how fast a computer can run using electricity A computer is basically a really detailed maze of electrical signals being sent over metal and semi-conductors As fast as computers have gotten we are reaching the point at which the computer chips that process data cannot get much smaller or faster using conventional electricity in transistors However the future of computers may be in Quantum photonic computers computers that use light for transmitting signals as opposed to electricity Photons are used to store information and can carry this information over very long distances in very short periods of time Quantum computers could also open up new ways of making computers as many of the materials now used to make computers could be substituted for lighter stronger materials Invisibility One of the coolest science fiction ideas is that there could be a material which can make someone invisible if they are wrapped in it allowing them to sneak around without being detected New metamaterials developed by optical engineers have already been used to make an object invisible to microwave radiation (this happened in 2006 at Duke University) These specially designed metamaterials according to physicist Michio Kaku can be used to bend light in weird ways that do not happen naturally If light waves can be bent around an object then they do not reflect off of that object and into your eyes and to you the object is not there Research continues with many people trying to make a material that can bend visible light [33] This means that an invisibility suit is a distinct possibility for the future Another way to make something invisible is being researched using holograms A hologram is a 3-D image projected


using lasers If there was a suit that could take a picture of the background behind a person and then project a hologram in front of that person all an observer would see is the background thus making the person in the suit invisible However things get complicated once the person in the suit wants to move the hologram projection would have to move with them

Communication One of the most important areas of technology that depends on optics is communication As you have seen devices like cell phones and computers communicate information using the waves of the electromagnetic spectrum As people all over the world continue to learn more about the way these waves behave we can look forward to more ways to communicate information You will learn much more about how these networks work in the next stages of this course Renewable Energy Enough sunlight falls on the earth in one day to power the entire energy used by humans in a whole year

Figure 153 Illustration of a metamaterial that bends light Adapted from Ref 34

Figure 154 United States Department of Energy solar array From Ref 35


None of the cool gadgets or ways to communicate are of much use if our world climate continues to change rapidly The science of optics is at the forefront of dealing with our constantly changing climate As you have already learned photovoltaic solar panels use the principles of optics to capture energy from sunlight and turn it into electricity without burning fuel As fuel becomes scarcer solar technology is improving to produce more and more of our electricity from renewable sources like the sun One such example of this new technology is the parabolic trough a curved mirror that focuses the sunrsquos rays on a single tube that runs down the center of the mirror This concentrated sunlight heats up the fluid inside the pipe the heated fluid is then used to heat steam in a conventional generator producing large amounts of electricity These troughs have been successful in the United States and other countries for years and more continue to be built every day There are many more exciting ways that optical science is contributing towards the future of the planet Whatever you are interested in the principles in this course will help you understand light and the fascinating ways it works

Figure 155 Sandias National Solar Thermal Test Facility in Albuquerque NM


Assessment Question 18 a

Question 18 b


Question 18 c What areas of technology were you the most interested in today

a) 3-D technology

b) Renewable Energy

c) Communication technology and Quantum computers

d) Invisibility

Question 18 d Which career did you think sounded the most interesting Do you think that there is a relationship between the career you were interested in and the technology you thought was the most interesting Why or why not

Vocabulary for Day 5 quantum computer one-point perspective metamaterials polarization parabolic trough photovoltaic panel transistor wave-particle duality


Bibliography [1] httpwwwcian-ercorgfellowcfm [2] Ancient Culture Japanese Gods and Myths Singapore Quantum books 1998 [3] httpcommonswikimediaorgwikiFileAmaterasu_cavejpg Permission = public domain copyright expiration [4] httpcommonswikimediaorgwikiFileAmon-ReJPG Permission = public domain copyright expiration [5] httpwwwcyhcomHealthTopicsHealthTopicDetailsKidsaspxp=335ampnp=152ampid=1730 [6] wwwwebvisionmedutahedu Used with permission from copyright holder [7] Feynman Richard QED The Strange Theory of Light and Matter Princeton Princeton Science Press 1985 [8] httpcommonswikimediaorgwikiFileEM_Spectrum3-newjpg [9] httpcommonswikimediaorgwikiFileMinolta-9000-M4771jpg Permission=public domain released by copyright holder [10] httpcommonswikimediaorgwikiFileLaser_optiquejpeg Permission=public domain Title 17 Chapter 1 [11] httpmedicineworldorgimagesblogs12-2007lasik-surgery-16190jpg [12] httpenwikipediaorgwikiFileGrid_illusionsvg Permission=public domain released by copyright holder [13] httpcommonswikimediaorgwikiFileGerman_postcard_from_1888png Permission=public domain copyright expiration [14] httpenwikipediaorgwikiFileGrid_illusionsvg Permission=public domain released by copyright holder [15] httpcommonswikimediaorgwikiFileBat_echolocationjpg Permission=public domain released by copyright holder [16] httpcommonswikimediaorgwikiFileOcean_surface_wavejpg Permission=public domain released by copyright holder Link to wwwpdphotoorg [17] httpenwikipediaorgwikiFileGodfreyKneller-IsaacNewton-1689jpg Permission=public domain copyright expiration [18] httpenwikipediaorgwikiFileChristiaan_Huygens-paintingjpeg Permission=public domain copyright expiration [19] httpenwikipediaorgwikiFileYoung_Thomas_Lawrencejpg Permission=public domain copyright expiration [20] httpenwikipediaorgwikiFileEinstein_1921_portrait2jpg Permission=public domain copyright expiration [21] httpcommonswikimediaorgwikiFileBlack_light_bulbjpg Permission=public domain released by copyright holder [22] httpcommonswikimediaorgwikiFileArizona_bark_scorption_glowing_ under_ultraviolet_lightjpg Permission=public domain released by copyright holder [23] httpwwwroeacukgalleryhk-beijing-05slides31820solar20telescope20at20sun Used with permission from copyright holder [24] httpcommonswikimediaorgwikiFileRoentgen-x-ray-von-kollikers-handjpg Permission=public domain copyright expiration


[25] httpcommonswikimediaorgwikiFileUS_Navy_031103-N-1126D-002_Hospital_Corpsman_2nd_Class_Adrian_Brown_uses_a_Gamma_Camerajpg Permission=public domain work of US Federal Government [26] wwwengaging-technologiescomeinstruction-cps-irhtml Used with permission from copyright holder [27] httpcommonswikimediaorgwikiFileMicrosoft-wireless-mousejpg Permission=public domain released by copyright holder [28] httpcommonswikimediaorgwikiFileTelevision_remote_controljpg Permission=public domain released by copyright holder [29] httpcommonswikimediaorgwikiFileQed_elementary_rulesjpg Permission=public domain released by copyright holder [30] httpscienzapertuttilnfinfnitconcorsosensaleHomePage_fileDatiMacchina20fotografica_fileimage002gif [31] httpenwikipediaorgwikiFileRoemerjpg [32] httpcommonswikimediaorgwikiFile3D_dusk_on_Desertjpg Permission=public domain work of US Federal Government Title 17 Chapter 1 [33]Kaku Michio Physics of the Impossible A Scientific Exploration into the World of Phasers Force Fields Teleportation and Time Travel New York Doubleday 2008 [34] httpwwwswitchedcom20100319scientists-one-step-closer-to-invisibility-suit [35] httpcommonswikimediaorgwikiFileSolar_Arrayjpg Permission=public domain work of US Federal Government Title 17 Chapter 1 [36] httpcommonswikimediaorgwikiFileSandia_power_towerjpg Permission=public domain work of US Federal Government Title 17 Chapter 1 References not cited in body of text

Falk D et al (1998) Seeing the light Optics in Nature Photography Color Vision and Holography Montreal JPH Wiley and Sons Millage J (Ed) (1998) Japanese Gods and Myths Singapore Quantum books Donnelly J amp Nicholas M (2007) Light Introduction to Optics and Photonics Springfield Ma New England Board of Higher Education Boyle G (2004) Renewable Energy Power for a Sustainable Future Oxford Oxford University Press

Introduction to Optics

11 What is Optics


13 The Basics of Light

14 Is light a wave


16 Light as a Particle

17 The Speed of Light



Question 1a None of these devices would exist without an understanding of optics Cell phones are able to send signals through empty space due to the technology developed through the application of optics Cameras would not be able to focus on the subject of a photo computers would not be able to send data through a network to bring you the internet and the television would not exist without the powerful knowledge contained within the field of optics Even though these devices work in complicated ways they exist because of the principles that you can learn about right in this ldquosuper-courserdquo Yes really You can learn about the principles that have allowed many highly paid engineers and scientists to create things like lasers cell phones and computers If you can learn the basic principles behind making these devices you could choose to join those who are creating the next generation of technological advances such as supercomputers improved lasers and invisibility suits If nature and the environment interest you know that knowledge of the electromagnetic spectrum has been essential to understanding the current climate of the earth including the problem of global climate change and its solutions

























































































14 Is light a wave









a) 2 miles or less

b) 5 miles or less

c) 10 miles or less







Experiment Review












































X-Rays





Gamma Rays












Infrared light







Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave





























































































14 Is light a wave









a) 2 miles or less

b) 5 miles or less

c) 10 miles or less







Experiment Review












































X-Rays





Gamma Rays












Infrared light







Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave











a) 2 miles or less

b) 5 miles or less

c) 10 miles or less







Experiment Review












































X-Rays





Gamma Rays












Infrared light







Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave








Experiment Review












































X-Rays





Gamma Rays












Infrared light







Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave









































X-Rays





Gamma Rays












Infrared light







Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave







Gamma Rays












Infrared light







Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave












Infrared light







Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave






Question 15 b


Microwaves







Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave








Radio waves












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave












120640 =119959119943

Where

λ = Wavelength





Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave








Assessment


Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave






Question 15 d


Question 15 e




















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave






















Quantum Theory

Question 16 b
































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave



































Question 17 e





























Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave

































Question 18 b



a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave







a) 3-D technology

b) Renewable Energy


d) Invisibility









11 What is Optics



14 Is light a wave











11 What is Optics



14 Is light a wave





Module 1 – Nature of...

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Transcript of Module 1 – Nature of...