1. Chapter 17 The Electromagnetic Spectrum
I. The Nature of Electromagnetic Waves

2. Electromagnetic energy is all around us.
Where does it come from???

3. It comes from the sun.

4. Electromagnetic Waves
The sun is producing an enormous amount of energy all the time. This energy pours off the sun as electromagnetic waves and rays. The different wavelengths determine the type of wave or ray it is.

5. Electromagnetic Waves
Transverse waves that have electric and magnetic properties.
Consist of changing electric & magnetic fields

6. Consist of changing electric & magnetic fields
Transverse waves that have electric and magnetic properties.
Consist of changing electric & magnetic fields

7. ELECTROMAGNETIC SPECTRUM

8. Radio Waves Have the longest wavelength and lowest frequencies.
Frequency ( Hz) to 104
Wavelengths (m) to 106

9. Radio Waves
Microwaves- (radio waves) shortest wavelengths and highest frequencies.
Can pass through glass and plastic.
Metals reflect microwaves.
Frequency ( Hz) to 106
Wavelengths (m) 10-4 to 10-1

10. Radio Waves Radar- Radio Detecting and Ranging.
Used to detect objects.
Used in military planes, ships and installations.
Safety - do not walk in front of airplane with radar on.

11. Radio Waves Radar is actually microwaves. Doppler
used for weather and police
Sometimes used in sport events.

12. Radio Waves Magnetic Resonance Imaging (M.R.I)
used for lots of medical purposes
like brain and spine disorders.

13. Infrared Rays
Felt as Heat - wavelengths a little shorter than visible light.
Have higher frequencies and shorter wavelengths than radio waves.
Frequency ( Hz) to 1012
Wavelengths (m) 10-6 to 10-4

14. Visible Light Shortest wavelengths are violet or purple. color
Shorter wavelengths and higher frequencies than infrared rays
Shortest wavelengths are violet or purple. color
The only part of the spectrum we can see.
Frequency ( Hz) 1015
Wavelengths (m) 10-7

15. Used to to treat jaundice for newborns.
Ultraviolet Light
Electromagnetic wavelengths shorter than visible light.
Used to to treat jaundice for newborns.
Over exposure can cause skin cancer.
Frequency ( Hz) to 1015
Wavelengths (m) to 10-7

16. X-Rays Electromagnetic waves with very short wavelengths
Can penetrate most matter.
Over exposure can cause cancer.
Used to see bones and structures.
Frequency ( Hz) to 1017
Wavelengths (m) to 10-9

17. Gamma & Cosmic Rays
Shortest wavelengths and highest frequencies on the electromagnetic spectrum.
Can kill some cancer cells.
Frequency ( Hz) to 1022
Wavelengths (m) to 10-15