1. Electromagnetic Waves and the EM Spectrum
Mrs. Molloy
6th Grade Science

2. Electromagnetic Waves…
Do not need matter to transfer energy.
Made by vibrating electric charges.
Travel by transferring energy between electric and magnetic fields.

3. EM waves are transverse waves
Move in a right angle to the direction of the energy
Have crests and troughs
Have the same properties as mechanical waves
Wavelength
Frequency
Amplitude

4. Making Electromagnetic Waves
When an electric charge vibrates, the electric field around it changes creating a changing magnetic field.

5. Making Electromagnetic Waves
An EM wave can travel in all directions.

6. What is the speed of EM waves?
EM waves travel 186,000 miles per second (speed of light)
EM waves travel slowest in solids and fastest in gases.
The speed of sound waves is only 760 miles per hour
Mechanical waves travel fastest in solids and slowest in gases

7. Electromagnetic Spectrum
The entire range of EM waves = electromagnetic spectrum.
Different parts interact with matter in different ways.
The ones humans can see are called visible light, a small part of the whole spectrum.
Long wavelengths = low frequencies and short wavelengths = high frequencies

9. RADIO WAVES Have the longest wavelengths
Lowest frequencies of all the electromagnetic waves.
Examples: AM/FM radio, GPS, MRI

10. MICROWAVES
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.

11. INFRARED RAYS
Infrared= Warm objects give off more heat energy than cool objects.

12. VISIBLE LIGHT EM waves we can see. Longest wavelength= red light
Shortest wavelength= violet (purple) light

13. Carry more energy than visible light
ULTRAVIOLET RAYS
Carry more energy than visible light
Used to kill bacteria. (Sterilization of equipment)

14. Too much UV radiation can cause skin caner
Use sun block to protect against (UV rays)
UV rays causes your skin to produce vitamin D (good for teeth and bones)

15. X- RAYS
Carry a great amount of energy
Can penetrate most matter.
Bones and teeth absorb

16. Too much exposure can cause cancer
X-Rays
Too much exposure can cause cancer

17. GAMMA RAYS
Shortest wavelength & highest frequency
Carry the greatest amount of energy and penetrate the most.

18. Used in radiation treatment to kill cancer cells.
Gamma Rays
Used in radiation treatment to kill cancer cells.
Can be very harmful if not used correctly.

19. Draw a line along the middle of your paper.
Title your drawing The EM Spectrum
Fold your paper in half. Label the middle Visible Light and then add the six other EM waves equal distances apart
Label the wavelengths and add the “Wavelengths (meters)” label
Draw and color seven pictures that show real world examples of the waves