Examining Light 2004

with Hands-On Activities

Compiled by, Marjorie Anne Wallace

Elementary Science Resource Teacher

2002-2005 / NNPS & NSF Coop Agreement

We will investigate the following: 1. What is light? 2.What are some sources of light around us? 3. What are opaque, transparent, &

translucent objects? 4. What is a light wave? 5.Are there any hands-on/minds-on activities

I can do to learn more?

National Science Education Standards

Physical Science: Content Standard B

As a result of the activities in grades K-4, all students should develop an understanding of light, heat, electricity, and magnetism.

Virginia Standards of Learning 5.3 a-e:

The student will investigate and understand basic characteristics of visible light and how it behaves. (*Key concepts, 5.3a-e, are listed in your teacher curriculum guide)

Our primary source of light is the sun. Light travels in straight lines at a speed of

186,000miles per second. *Light waves travel faster than sound

waves! Light energy from the sun travels through

space , reaches earth, and some of it turns to heat energy and warms the earth’s air.

Light from the sun also travels to the cells of green plants (producers) and is stored as energy.

When light reaches an object, it is absorbed, reflected, or passes through it.

Humans have two light detectors.

Do you know what they are called?

SUN=warms air, water, and land. Fire=provides heat,

light, and cooking fuel. Lightning= Firefly= Flashlight= Light bulb= Laser beams= Optical telephone fibers=*Traffic lights= *AIMS: Primarily Physics:

Light Sources Activity

1. A person will see a flash of lightning before they hear the thunder that goes with it because?

*SOL 2003 querie #14/CORE 1 Exam (5.3e)

2.Can you draw a long wavelength and a short wavelength next to it? *SOL2003 queire #9/CORE 1 Exam(5.3a)

3.What scientific tools are used to study light? *SOL2003/CORE 2 Exam(5.3b)

4. Can you contrast objects that are transparent, translucent, and opaque? *SOL2003/CORE 2 Exam(5.3d)

If light travels through an object it is =transparent

If light is blocked by an object and a dark shadow is cast it is= opaque.

If some light passes through but not all and a light shadow is present it is=translucent.

*AIMS:Primarily Physics: Just Passing Through Activity

Glass of water School bus

window Notebook paper Waxed paper Plastic wrap Tissue paper Cardboard Textbook Hand lens…

The windows on a school bus, A clear empty glass, A clear window pane, The lenses of some

eyeglasses, Clear plastic wrap, The glass on a clock, A hand lens, Colored glass… ALL of these are transparent.

Yes, we can see through them because light passes through each of them.

Thin tissue paper, Waxed paper, Tinted car windows, Frosted glass, Clouds, All of these

materials are translucent and allow some light to pass but the light cannot be clearly seen through.

Heavy weight paper, Cardboard Aluminum foil, Mirror, bricks, buildings, Your eyelids and hands, Solid wood door, All of these objects are

opaque because light cannot pass through them at all.

They cast a dark shadow.

Simple Activity: 1 working flashlight 1. Shine a flashlight on a wall. 2. Does light from the flashlight reach the

wall? How do you know? 3. What evidence do you have showing

light travels in a straight line? 4.Record answers in your science journal 5.Move closer with the flashlight. Any changes? *Write a story about light.

The traditional hands-on/minds-on activities: 1. “slinky lab: A Wave Simulation!” as well

as 2. “Waves in Action” (visual learner), and 3. “Act It Out!Waves Tall and Small”

(kinesthetic learner) activities will help children understand waves better.*Science Museum of Virginia: Light & Sound

www.smv.mus.va.us

*Unitedstreaming movies:”Out of Darkness: An Introduction to Light: Facts About Light.”(auditory & visual learners). *Check with your building technology dept for

your schools password.

Light waves are three dimensional.

Light waves vibrate in all planes around a center line.

The waves have high points called “crests.”

Waves also have low points called “troughs.”

*The distance from one crest to the next crest is called a “wavelength.”

*The number of waves passing a given point in one second is called the “frequency.”

wavelength

*A Science Museum of VA:Light Science Activity

Notice the wavelength is long(Radio waves) and gets shorter (Gamma Rays)

Materials: 1 long spring or rope 1. Teacher and a strong student will hold either

end of the coiled spring tightly braced against their body.

2.Teacher will walk away from the student until the spring is loosely stretched between them.

3.Gently snap the spring up and down once to send a wave of energy to the student’s hand. It will bounce back, or reflect, from the stationary end.

4. Point out each wave has a crest (high half) and a trough (low half). Check for understanding

*Science Museum of VA A Wave Simulation Activity/Demo ORGEMS:”Invisible Universe”Comparing Wave Makers

Electromagnetic radiation can be described as a stream of photons. Each photon traveling in a wave-like pattern, moving at the speed of light and carrying some amount of energy.

The only difference amongst radio waves, visible light, and gamma-rays is the amount of energy of the photons. Radio waves have photons with low energies. Microwaves have a little more energy than radio waves. Gamma-rays and cosmic rays have highest energy waves and are the deadliest.

*Page info from NSTA Conference 2004

*Page info from NSAT Conference 2004

Don’t’ forget…longest waves (radio) ..to shortest waves (cosmic)

Materials: 1. 9 volunteers 2. paper & pencil.

These 2 activities help to explain the electromagnetic spectrum and dispel some of the common misconceptions.

*Science Museum of VirginiaActing It Out! Activity +Scaling the Spectrum Activity ORGEMS: Invisible UniverseComparing Wave Makers I.

1) Light travels in straight lines2) Light travels much faster than sound3) We see things because they reflect light

into our eyes4) Shadows are formed when light is blocked

by an object

Reflection from a mirror:

Incident ray

Normal

Reflected ray

Angle of incidence

Angle of reflection

Mirror

The Law of ReflectionThe Law of Reflection

Angle of incidence = Angle of reflectionAngle of incidence = Angle of reflection

In other words, light gets reflected from a surface at ____ _____ angle it hits it.

The same !!!

Smooth, shiny surfaces have a clear reflection:

Rough, dull surfaces have a diffuse reflection.

Diffuse reflection is when light is scattered in different directions

Two examples:

1) A periscope

2) A car headlight

Refraction is when waves ____ __ or slow down due to travelling in a different _________. A medium is something that waves will travel through. When a pen is placed in water it looks like this:

In this case the light rays are slowed down by the water and are _____, causing the pen to look odd. The two mediums in this example are ______ and _______.

Words – speed up, water, air, bent