1. Unit 5 – Optics
Science 8 - Palmer

2. Visible Light Spectrum
Can be seen due to the dispersion of white light through a prism

3. The constituent colours of white light are:
Red
Orange ROY G BIV
Yellow
Green * Red has the smallest
Blue refraction and violet has
Indigo the greatest
Violet

4. When a laser is shone through a prism, the light will refract but not disperse. Why? A laser light has only one colour.

5. Electromagnetic Radiation

6. Electromagnetic Radiation
Types of electromagnetic radiation:
1. Radio Waves: the longest wavelength and lowest energy and frequency
Can be used to help us see inside our bodies to diagnose illness (MRI)

7. MRI Cutaway Section
Magnetic
Resonance
Imaging

8. 2. Microwaves: have the shortest wavelength and highest frequency of all radio waves
Ex. Microwave ovens, telecommunication satellites, radio telescopes, radar (remote sensing)

9. How Microwaves Work
Microwave ovens use a specific frequency that is strongly absorbed by water molecules in food

10. 3. Infrared Waves: longer wavelength and lower energy and frequency
Infrared means below red
Also called heat radiation
Ex. Remote controls, computer, heat lamps, motion sensors

11. Infrared Radiation
Infrared scanning is used for medicine, space travel and scanning the surface of Earth (LANDSAT)

12. 4. Visible Light Spectrum
Can be continually detected by our eyes

14. 5. Ultraviolet Waves: shorter wavelength and higher energy and frequency
Very energetic
Have the ability to kill bacteria in food, water and medical supplies
Ex. Sun, detect fingerprints

16. 6. X-rays: have a shorter wavelength and higher energy and frequency than UV.
Used to photograph teeth, bones and the inside of machines
Ex. Security screening

17. X-Ray Imaging

18. 7. Gamma Waves: have the highest energy and frequency and the shortest wavelength.
Result from nuclear reactions.
Produced by the hottest regions of the universe.

19. Gamma Rays: Nuclear Explosion
Star Formation in deep space

20. Electromagnetic Radiation…
Generally, higher energy electromagnetic radiation is more harmful to humans. The Earth’s atmosphere is able to protect us from some of the more dangerous electromagnetic radiation present in space, making the Earth a safe place for humans.

21. End of Part 3