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Light!
It's all around us.
But what is it?
Where does it come from?
And what does light have to do with color?
Light is a kind of energy that travels in
waves.
It is made when matter is heated up or gains
energy.
Excess energy is released, in part, as light.
This energy is called electromagnetic radiation.
When we talk about light, we usually mean
visible light, which is the light that we
can see with our eyes, but there are more
types of electromagnetic radiation that are
invisible to us, including radio waves, microwaves,
x-rays, and gamma rays.
Scientists can detect and measure invisible
radiation with special tools.
Together with visible light, all these types
of radiation are called the electromagnetic
spectrum.
All electromagnetic radiation travels in waves,
but different types have different wavelengths.
The wavelength of electromagnetic radiation
or light is connected to how much energy it has.
Light with a longer wavelength, like radio
waves, has less energy, while light with a
shorter wavelength, like gamma rays, has more
energy.
Visible light makes up only a tiny part of
the electromagnetic spectrum, but it includes
every color we can see.
The most important source of light here on
Earth is the Sun.
We call ordinary sunlight white light, but
it actually includes all the colors of visible
light.
These colors can be revealed when white light
goes through a prism.
When light passes through a prism or something
like it, it slows down a little bit and bends.
Some parts of the light slow more than others,
and the light spreads out into the colors
of the spectrum.
If you want to see all of the colors in the
visible light spectrum, look no further than
a rainbow!
Rainbows are made when water droplets in the
air bend sunlight much like a prism.
Usually when we talk about a rainbow, we say
it is made of seven colors - red, orange,
yellow, green, blue, indigo and violet.
Each color has a different wavelength.
Red has the longest wavelength in the spectrum
of visible light, and violet has the shortest
wavelength.
All the other colors have wavelengths in between
the two.
The colors of a rainbow are always in the
same order, because the colors are arranged
according to their wavelengths!
Red is always on the outside, because red
has the longest wavelength - and violet is
always on the inside, because violet has the
shortest wavelength.
Electromagnetic radiation with a wavelength
outside the visible light spectrum is invisible
to our eyes.
Light with a longer wavelength than the reddest
red our eyes can see is called infrared light.
Light with a shorter wavelength than the most
violet violet we can see is called ultraviolet.
When we look at an object, we are actually
seeing the light that is bouncing off of it.
A green leaf looks green because the leaf
absorbs all of the colors in the spectrum
except for green, which it reflects.
When the green light enters our eyes, our
brain tells us it looks green.
Things that look white are reflecting almost
all of the visible light shining on them,
and things that look black are absorbing almost
all of the visible light shining on them.
Light, both visible and invisible, is all
around us.
It travels from its source as a wave, bringing
energy with it.
Without light, there would be no colors!
Take a look at the world around you, and remember!
Everything you can see is just different wavelengths
of reflected light.
Goodbye till next time!
