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What is Light?There are many sources of
light!
SOLAR ECLIPSE
Do you know some examples of light?
Light sources (something that makes light)
Energy and Light Energy: the ability to do work
Light is ENERGY we can SEE
LIGHT ENERGY can change into HEAT ENERGY which can be used for work.
Light From Nature Natural Light:
Light from nature What can you think of?
The SUN! Lights our world and warms it We could not exist without the sun
(plants, cold, darkness)
The Sun The Sun is a star!
It’s the closest one to us so we get most of our light and heat from the Sun and not other stars (which are too far away!)
How important is the sun really?
Bill Nye and Solar Power
We see the sun everyday and we know it’s a big star with lots of energy but how much energy does it really have?
Solar Magnifier Video
The Moon Sometimes at night, the moon helps us
see. BUT the moon doesn’t make light The Sun’s light bounces off the
moon and makes it look like the moon is shining.
More Natural Light
Natural Light Natural light is really important to
humans But we can’t control them
We can’t turn the Sun on and off when we want to
Some of the animals that we saw before use bioluminescence to survive (communication, attract food)
Artificial Light A long time ago, humans only had
natural light How would their lives be different?
Artificial Light: Fire Humans learned how to control natural
light sources They found out how to make fire!
They used fire to keep warm, cook with and also do things after the Sun went down
Fire People learned they could burn other
things than wood to make light Examples?
Wax – Candles Oil – Lamps Chemicals - Sparklers
Artificial Light Artificial: Made by humans Artificial Light: Light made by humans
Most are made by electricity This is another type of energy
Artificial light is easy to control because they can be turned on and off with a switch
Bouncing Light? We talked about sunlight bouncing off
the moon Artificial light bounces too! The reason we see road signs is because
light from the car or streetlights bounces off the sign!
$ The Costs $ Natural Light is always free! Artificial Light always costs money!
Buying lamps, electricity, oil, batteries, flashlights
Even candles, sparklers and reflective clothing
We should conserve money and energy by shutting off artificial lights when we can!
OPEN A WINDOW!
Natural Light Artificial Light
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