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

2. EQ: What is the electromagnetic spectrum?
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.
If I have a wave with a large wavelength, will I have a wave with high or low frequency?
EQ: What is the electromagnetic spectrum?

3. Electromagnetic Spectrum
EQ: What is the electromagnetic spectrum?
Made up of 7 different types of waves
What is 10 3? (1000) What is 10-3? (.001) Which wave has more energy – x ray or microwave? Explain how you know the answer using wavelength and frequency.

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
EQ: What is the electromagnetic spectrum?

5. Microwaves – shorter wavelengths and higher frequency
Microwave ovens and cell phones most common use
EQ: What is the electromagnetic spectrum?

6. EQ: What is the electromagnetic spectrum?
a transmitter and a receiver
cell phones depend on an overlapping network of cells, or areas of land several kilometers in diameter
cell tower in the center of “cell” receives and sends microwaves
Cell Phones
EQ: What is the electromagnetic spectrum?

7. Radar – shortest wavelength microwaves
Stands for radio detection and ranging
Used to locate objects
Use radio waves and the Doppler effect to calculate speed of vehicles
Baseball pitcher, policeman
EQ: What is the electromagnetic spectrum?

8. EQ: What is the electromagnetic spectrum?
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
Sense but not see
EQ: What is the electromagnetic spectrum?

9. EQ: What is the electromagnetic spectrum?
Infrared Waves
Thermogram – pictures taken by infrared camera. Shows regions with different temperatures with different colors
Used to detect motion of clouds, growth of plants
Developed by the military
EQ: What is the electromagnetic spectrum?

10. EQ: What is the electromagnetic spectrum?
Visible Light
EQ: What is the electromagnetic spectrum?
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
Smallest section of the spectrum

11. EQ: What is the electromagnetic spectrum?
Visible Light
Waves
EQ: What is the electromagnetic spectrum?

12. EQ: What is the electromagnetic spectrum?
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
Yellow is what we see, blue is what a bee sees
EQ: What is the electromagnetic spectrum?

13. EQ: What is the electromagnetic spectrum?
Ultraviolet Waves
UV lamps used to kill bacteria
UV waves help produce vitamin D in the body, cause sunburn
Help newborns who have jaundice
EQ: What is the electromagnetic spectrum?

14. EQ: What is the electromagnetic spectrum?
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
Where are the x rays absorbed? (bones) What would a broken thumb look like on this x ray? (black crack on the thumb)
EQ: What is the electromagnetic spectrum?

15. EQ: What is the electromagnetic spectrum?
Gamma Rays
Shortest wavelength and highest frequency
Used in radiation therapy to kill cancer cells
Examine body’s internal structure
Supernova
As the wavelength of an EM Wave decreases, what happens to the frequency? (Increases) What happens to the energy? (Increases)
EQ: What is the electromagnetic spectrum?

16. Class Work and Homework
Fill In
What did I learn
Confused
Say
Read pages 79– 86
Electromagnetic spectrum jumble
questions 1-6 and page 87 “Are cell phones harmful?”
EQ: What is the electromagnetic spectrum?