1. Light, Illumination, and Materials
Grade 1

2. Content Topics Properties and actions of light
Connection of light in air to light in space, versus light incident on a surface

3. Each color of light has its own energy.
What is Light?
Light is energy.
Each color of light has its own energy.
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4. All Types of Light (not included in standard)
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5. Night Vision
The primary source of infrared radiation is heat or thermal radiation.

6. Constant Speed of Light (not included in standard)
Light speed is constant in a vacuum (in space)
3 x 108 m/s
186,000 miles/sec
670 million mph
It takes time for light to travel.
New Horizons
Fastest Spacecraft Launch
36,000 mph
Image Credit: NASA

7. Some of Our Neighbors Sun 8 minutes Proxima Centauri 4.2 LY Sirius
Andromeda Galaxy
2.5 x 106 LY

8. Practice
If we look at Proxima Centauri in our night sky, which is 4.2 LY away, are we seeing it as it is now or as it was in the past? Explain.

9. How does “light” interact with matter?
Light interacts differently with different types of matter. 
Surface Material Angle Energy

10. Light energy gets absorbed Light bounces Light changes direction
What does light do?
Light travels
Light energy gets absorbed
Light bounces
Light changes direction
Light allows us to see objects

11. Examples of What Light Does
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12. Practice What do opaque materials do?
Block light, reflect light, and/or absorb light
What are some examples of opaque materials?
Wood
Paper Bag
Mirror

13. Transparent Materials
Light travels through a material that is transparent.
Light also travels through space.
Air
Air
Glass
Light Ray

14. Sunlight on Our Moon
The Sun’s energy travels through space to the Moon.
Light energy reflects from the Moon.
Image Credit: NASA

15. We See Light Reflected from the Moon
Simulation by watchersnews.com

16. Practice
Do we see the light travel from a light to our desk? Do we see it move through the air? How do we know it is there?
We cannot see the light traveling through a transparent material, like air. We know it is there because we see it reflected from objects that are at a distance from the light. We also know the light is in the air when we feel the sunlight.
Do we see the light energy traveling through space from the Moon to us? How do we know that it does?
We cannot see the light traveling through space. We know it is there because we see it reflected from the Moon.

17. Reflection
Objects with very smooth surfaces bounce a lot of light from the surface.
JWST Telescope Mirror
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18. Smooth vs Rough Parallel Reflection Diffuse Reflection
Light is bounced in a single direction
Diffuse Reflection
Light is bounced in various directions
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19. Practice Parallel or Diffuse
What type of reflection comes from your bathroom mirror?
Parallel
What type of reflection comes from wood kitchen cabinets?
Diffuse

20. Our Atmosphere Sunlight passes through our atmosphere.
Sunlight allows us to see objects.

21. Practice Can we see objects in the dark? When do we see objects?
No, we cannot see objects if it is completely dark.
When do we see objects?
We see objects when there is light.

22. Atmosphere The atmosphere is a type of material.
Light does different things depending on the material.
Our atmosphere makes the light from stars look different.
Fuzzy or Bleary
Twinkling
No stars

23. Twinkling Atmosphere
Stars are like a light bulb. They shine bright and steady.
The atmosphere causes starlight to change direction many times, so it looks like the stars are twinkling.

24. “Twinkle, twinkle, little atmosphere…”
Video by pixabay.com