Electromagnetic Waves Chapter 3 Electromagnetic Spectrum Lesson 3-1 .
Electromagnetic Waves (light) & the Electromagnetic Spectrum.
Transcript of Electromagnetic Waves (light) & the Electromagnetic Spectrum.
Waves All waves carry … ENERGY!!!
Medium material through which a wave
transfers ENERGY solid, liquid, gas, or combination some can even move through
scpace
Electromagnetic Waves (light) Light waves are transverse waves In transverse wave the medium
moves perpendicular (opposite) to the motion of the wave.
Medium
Motion of wave
EM (electromagnetic) Waves EM waves travels fastest when there is
no matter (particles) in the way.
Does not need a medium to travel ex: light can travel trough space
Speed depends on the medium slowest fastest medium vacuum (solid – liquid - gas) (space)
ElectromagneticRadiation
Energy emitted from the sun that travels to earth through space. They contain electrical and
magnetic properties. Have some magnetic and some
electrical properties to them.
Electromagnetic waves travel VERY FAST – around 300,000 km/s (the speed of
light).
At this speed they can go around the world 8 times in one second!!!
Electromagnetic Spectrum—name for the range of electromagnetic waves when placed in order of increasing frequency
RADIO WAVES
MICROWAVES
INFRARED RAYS
VISIBLE LIGHT
ULTRAVIOLET RAYS
X-RAYS
GAMMA RAYS
Global Positioning Systems (GPS) measure the time it takes a radio
wave to travel from several satellites to the receiver,
determining the distance to each satellite.
Used in microwave ovens.
Waves transfer energy to the water in the food causing them to vibrate which in turn transfers energy in the form of heat to the food.
Infrared Waves
• You can feel these as warmth on your skin
• Warm objects give off more heat energy than cool objects.
Thermogram—a picture that shows regions of different temperatures in the body. Temperatures are calculated by the amount of infrared radiation given
off. Therefore people give
off infrared rays.Heat lamps give off
infrared waves.
VISIBLE LIGHT
• Electromagnetic waves we can see.
• Shorter wavelength and higher frequency than infrared rays.
• Longest wavelength= red light
• Shortest wavelength= violet (purple) light
When light enters a new
medium it bends
(refracts). Each wavelength
bends a different amount
allowing white light to
separate into it’s various
colors ROYGBV.
ULTRAVIOLET RAYS
• Shorter wavelength and higher frequency than visible light• Carry more
energy than visible light
X- RAYS
Shorter wavelength and higher frequency than UV-rays
Carry a great amount of energy
Can penetrate most matter.
Bones and teeth absorb x-rays. (The light part of an x-ray image indicates a place where the x-ray was absorbed)
Used by engineers to check for tiny cracks in structures. The rays pass through the cracks and the cracks appear dark on film.
GAMMA RAYS
Shorter wavelength and higher
frequency than X-rays
Carry the greatest amount of energy and penetrate the
most.
The Incredible
Hulk was the victim of gamma
radiation.
Brief SUMMARY A. All electromagnetic waves
travel at the same speed. (300,000,000 meters/second) in a vacuum.
B. They all have different wavelengths and different frequencies. Long wavelength-lowest frequency Short wavelength highest frequency
The higher the frequency the higher the energy.
Doppler Effect An observed change in the
frequency of a wave when the source or observer is moving.
The pitch of a sound, high or low, depends on the frequency of sound waves.
Frequency changes when the source is moving.
example
example
Refraction
Refraction is the bending of waves as they pass from one medium into another.
Interference
Interference is the combination of two or more waves that exist in the same place at the same time.
Constructive interference always results in a new wave that is bigger than the original waves.
Destructive interference always results in a new wave that is smaller than the largest of the original waves.
Examples