1. Welcome to a power point presentation on LIGHT.
We will investigate the following:
1. What is light?
2.What are some sources of light around us?
3. What are opaque, transparent, & translucent
objects?
4. What is a light wave?

2. Light Our primary source of light is the sun.
Light travels in straight lines at a speed of 186,000miles per second.
*Light waves travel faster than sound waves!
When light reaches an object, it is absorbed, reflected, or passes through it.

3. Sensing Light Humans have two light detectors.
Do you know what they are called?

4. How many sources of Light can you list and explain?
SUN=warms air,
water, and land.
Fire=provides heat, light, and cooking fuel.
Lightning=
Firefly=
Flashlight=
Light bulb=
Laser beams=
Optical
telephone
fibers=
*Traffic lights=

5. Can you answer this question?
Why does a person see a flash of lightning before they hear thunder?
Because light travels faster than sound

6. What happens when light strikes an object
If light travels through an object it is =transparent
If light is blocked by an object it is= opaque.
If some light passes through but not all it is=translucent.

7. What happens when light hits these objects?
Glass of water
School bus window
Notebook paper
Waxed paper
Plastic wrap
Tissue paper
Cardboard
Textbook
Hand lens…

8. Transparent objects: The windows on a school bus, A clear empty glass,
A clear window pane,
The lenses of some eyeglasses,
Clear plastic wrap,
The glass on a clock,
A hand lens,
ALL of these are transparent. Yes, we can see through them because light passes through each of them.

9. Translucent objects Thin tissue paper, Waxed paper,
Tinted car windows,
Frosted glass,
Clouds,
All of these materials are translucent and allow some light to pass but the light cannot be clearly seen through.

10. Opaque objects: Heavy weight paper, Cardboard Aluminum foil,
Mirror, bricks, buildings,
Your eyelids and hands,
Solid wood door,
All of these objects are opaque because light cannot pass through them at all.
They cast a dark shadow.

11. What is light really? Electromagnetic radiation waves
The waves have highest point is called “crests.”
Waves also have low points called “troughs.”
*The distance from one crest to the next crest is called a “wavelength.”
The distance from the crest to the trough is the amplitude
wavelength
*A Science Museum of VA:
Light Science Activity

12. What happens when light hits an object?
Reflects = bounces off an object at the same angle.
Refracts = light bends when it goes through water.
Absorbed= light enters an object and stays in the object

13. Compare and contrast reflection and refraction
Reflection Refraction

14. Colors
We have a famous name to help us remember the colors we can see
ROYGBIV

15. What Does ROYGBIV MEAN R= Red O=Orange Y= Yellow G= Green B= Blue
I= Indigo
V=Violet

16. Primary Colors

17. We can make every other color from the primary colors

18. Notice the wavelength is long(Radio waves) and gets shorter (Gamma Rays)

19. Electromagnetic Spectrum
Radio waves= used for communication
Microwaves = used for communication and heating food
Infrared waves = used for heat
Visible light = allows us to see color
Ultraviolet waves = produce vitamin D but too much is cancer

20. Electromagnetic Spectrum Continue
X-Rays = used to see bones
Gamma Rays = Help Cure Cancer