1. Waves of the Electromagnetic Spectrum
EQ: What is the electromagnetic spectrum?

2. Vocabulary Electromagnetic Spectrum
Range of electromagnetic waves when they are ordered by increasing frequency
Remember all EMW travel at the same speed, but they have different wavelengths and frequencies
As the wavelength decreases, the frequency increases
The amount of energy carried by EMW increases as its frequency increases.

3. Electromagnetic Spectrum
Made up of 7 different types of waves

4. Radio Waves - EMW with longest wavelengths and lowest frequencies
Can travel through a vacuum but most of our radio waves travel through air.
1. Antennas pick up radio waves from the air.
2. Then the radio waves go to the wires in your radio
3. The radio converts the EMW into sound that comes out your radio

5. Microwaves – shortest wavelengths and highest frequency of radio waves
Microwave Ovens most common use
Microwave gives off EMW that bounce around the inside of the oven and penetrate the food
Water molecules in the food absorb the energy from the waves, causing the food to get hot
Can pass through plastic and glass, not metal
Microwaves also used for cellular telelphone calls

6. Radar – short wavelength microwaves (radio waves)
Stands for radio detection and ranging
Used to locate objects
Use radio waves and the Doppler effect to calculate speed of vehicles

7. Magnetic Resonance Imaging (MRI)
Radio waves used in medicine to produce pictures of tissue in the human body

8. Infrared Waves
Give off heat – heat lamp, electric stove, toaster. Humans can sense it
Have shorter wavelengths and higher frequencies than radio waves
Infra means below – below red on the color spectrum
Thermogram – pictures taken by infrared camera. Shows regions with different temperatures with different colors
Used to detect motion of clouds, growth of plants

9. Visible Light The light we can see
Longest wavelength of visible light are red, shortest is purple
Rainbow or prism refracts, or bends the light waves to produce different colors

10. Visible Light
Waves

11. Ultraviolet Rays UV rays
Ultra is Latin for beyond, so these waves are just beyond the color violet
Carry more energy than visible light because they travel at a higher frequency
UV lamps used to kill bacteria
UV waves help produce vitamin D in the body, cause sunburn

12. X - Rays
Carry more energy than UV rays because of their higher frequency
Can penetrate most matter with the exception of bone and lead. These are too dense

13. Gamma Rays Shortest wavelength and highest frequency
Used in radiation therapy to kill cancer cells
Examine body’s internal structure
Supernova

14. Class Work and Homework
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What did I learn
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Read pages 79– 86, questions 1-6 and page 87 “Are cell phones harmful?”