1. Chapter 9.1 Notes Part 2

3. Infrared Radiation Infrared radiation has wavelengths of about one millimeter. Infrared radiation includes thermal radiation.

4. For example, heat is transferred from an electric heater, by burning wood or coal, and by the sun through infrared waves. Infrared radiation is not visible, you cannot see it.

5. A person’s temperature can be measured with an electronic thermometer to detect infrared radiation. Infrared photographs are used to detect heat leaking from houses.

6. Infrared images obtained by satellites and airplanes can be used for weather and to find forest fires that are obscured by smoke. Finally, remote-controlled devices use infrared radiation.

7. Demonstration – Night Vision Goggles and Infrared Flashlight!

9. Visible Light Visible light is a very small part of the electromagnetic spectrum, but it is the most important part. Sight is a result of our eyes detecting visible electromagnetic waves.

10. 1. The human eye can detect the difference in colors in wavelengths. 2. Violet has the shortest wavelength and highest frequency while red has the longest wavelength and lowest frequency.

11. 1. ROYGBIV – Colors 1. Red 2. Orange 3. Yellow 4. Green 5. Blue 6. Indigo 7. Violet

12. The sun radiates white light which is light that mixes in equal amounts of light of all colors. When white light falls on an object, molecules on the object’s surface absorb part of the light and reflect the rest.

13. Color Spotlights

15. Ultraviolet Radiation 1. Ultraviolet radiation cannot be seen by the human eye. 2. Sunlight contains ultraviolet waves, which can burn or tan your skin.

16. Ozone molecules in the Earth’s upper atmosphere absorb most of the ultraviolet waves from the sun. A small dose of ultraviolet radiation is beneficial to humans, but larger amounts can cause cancer and cataracts. Ultraviolet wavelengths are used in water purifiers to kill bacteria and virus.

17. Demonstration – UV Light Pens

19. X Rays X Rays are high-energy waves that have great penetrating power. X Rays are used in medicine, in airport security, to detect fake gems and art, and in checking for flaws in welding.

20. X Rays have enough energy to pass through human tissue, but not enough to pass through bones or teeth. X Rays can be dangerous if not used with caution. Overexposure to X Rays damages healthy cells and can cause cancer. This is why X Ray technicians wear protective lead aprons.

22. Gamma Rays Gamma rays have a wavelength of less than ten trillionths of a meter. Gamma rays have higher frequency and wavelength than X rays, and they are more penetrating than X Rays.

23. Gamma rays are produced by nuclear reactions. They are used in many medical applications and used to destroy bacteria on food.