1. Properties of Light

2. The Sun The sun is a star (made of plasma).
Many explosions happen on the sun (like atomic bombs) that create energy.
This energy (called radiation) travels in all directions.

3. How Does Energy Travel? Energy travels in waves (like water).
The close waves are STRONG.
Waves that are far away are WEAK.

4. Which Side is Stronger: Left or Right?

5. Electromagnetic Radiation
The sun is so powerful that it creates 7 different kinds of radiation.
Some of this radiation is strong (waves close together); some of it is
weak (waves far apart).
All the different kinds of radiation is organized in an Electromagnetic Spectrum.

6. Electromagnetic Spectrum
There are 7 kinds of radiation in the electromagnetic spectrum:
Radiowaves, Microwaves, Infrared Radiation, Visible Light, Ultraviolet Radiation, X-Rays, and Gamma Rays.

7. The Electromagnetic Spectrum
Radiowaves – weak waves that give your radio or TV the energy to work. (can you see them?)
Microwaves - weak waves that can cook your food or used for cell phones and radar. (can you see them?)
Infrared Radiation – weak waves coming from something that is hot. (can you see them?)
Visible Light – the only radiation you can see.

8. Continued…
Ultraviolet Radiation – strong radiation that can make you tan and get cancer. (Can you see them?)
X-Rays – dangerous radiation that can go through to your bones. (can you see them?)
Gamma rays - the most powerful radiation. Very dangerous. Found in a nuclear explosion.

9. Visible Light Humans can only see visible light.
Visible light is made up of all of the colors of the rainbow:
Red
Orange
Yellow
Green
Blue
Indigo
Violet

10. How visible light travels…
Visible Light travels in waves…
BUT, the waves are so small that from far away it looks like a straight line.
SO…from now on we will ONLY say that light travels in a straight line.

11. Light Does 4 Things When it Hits an Object:
Reflection
Transmittance
Absorption
Refraction

12. The 2 Angles in a Reflection

13. How are the 2 angles related?
The angle of incidence and the angle of reflection are ALWAYS the same!!!

14. Colors

15. Remember: The colors of the rainbow are:
Red, Orange, Yellow, Green, Blue, Indigo, and Violet.
All the colors of the rainbow are ROY G. BIV.

16. Prisms What did you notice when the light hit the prisms???
The reason a rainbow appeared is because the light was...
REFRACTED.

17. Visible Light Each color of the rainbow has a different size wave.
Some colors are stronger than others
Red is weakest
Violet is strongest.

18. Visible Light What does this say about white light (visible light)?
VISIBLE LIGHT (white light) IS MADE UP OF ALL COLORS OF THE RAINBOW!!!!!

19. Colors White light is hitting the apple.
Every color of the rainbow is being absorbed by the apple EXCEPT the color red.
The red light that is reflected bounces to your eyes and you see red.

20. Lenses

21. Lenses
A lens is a clear object that refracts light so that you can see a bigger version of an object.

22. LIGHT TEST The following vocabulary words will appear on your test:
Radiation
Electromagnetic spectrum
Radio waves, Microwaves, Infrared Radiation, Visible Light, Ultraviolet Radiation, X-Rays, Gamma Rays
Reflection, Refraction, Absorption, Transmittance
Angle of Incidence & Angle of Reflection
White Light
ROY G. BIV
Prism
Lens

23. LIGHT TEST In order to pass, you must know the following:
What is the electromagnetic spectrum and how much is visible to humans?
How does visible light appear to travel?
What 4 things can happen when visible light hits an object?
How are the angle of incidence and angle of reflection related?
How are humans able to see objects?
Why are objects a certain color?
Which kind of lens would you use to see different sized things?