What is Light? - WordPress.com
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Transcript What is Light? - WordPress.com
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 from nature
What can you think of?
The
Light:
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