Hi Folks! Here's a fun, short science video showing how to use a prism
to separate sunlight into a rainbow of colors. As you can see, with a little work and a sunny
day you can get a pretty nice result.
I bought this prism at a local store called Focus Scientific
that sells telescope and other optical equipment. It's a simple five sided piece of glass with
three sides forming a triangle.
To demonstrate it in action I have this board on a tripod so I can
arrange it any way I want. On top I've tape these two pieces of cardboard
with a small gap between them.
I start by allowing only a thin slit of sunlight to go through this gap.
That's to make sure that most of the light I'm using is coming from one direction only.
As you can see, even with this paper far away, this light appears white on the paper.
Now I put my prism in the way of the light. You'll notice that the light no longer continues
in a straight line. And it you look closely you can see all the
visible colors that that sunlight is made up of.
I'll be talking only about visible light in this video.
Having found a good location for the prism, I tape it in place.
How does it work?
Visible light is made up of multiple electromagnetic waves with different wavelengths.
Those wavelengths represent different colors, red, orange, yellow, green, blue, indigo and
violet. On this side of the prism they're all overlapping
and going in the same direction. But when they cross the boundary between the
air and the glass of the prism, they bend. This bending is called refraction.
When they exit the prism, going from glass to air, they bend again.
The key is that the amount they bend by is different because of the different wavelengths,
or colors.
The result is that red light will bend something like this when entering the prism,
and like this when exiting the prism. But violet light will bend something like
this when entering the prism, and like this when exiting the prism.
So they enter going in the same direction but leave going in different directions.
And when we put this paper in the way of the light,
we see the different colors separated. Putting the paper on a slant helps spread
it across more area, so we can see the colors more clearly.
And that's how a prism works to make a rainbow of colors.
What if you don't have a fancy tripod or prism? Get a box instead and tape some white paper
to the top along with the two pieces of cardboard for
the gap. Fill a plastic or glass container with water,...
and use that to bend the light. It may not be as good as a prism but you'll
see some color separation at the edges.
Well thanks for watching!
See my youtube channel, rimstarorg, for more fun science videos like this.
That includes another where I show how this same refraction is used
by a Fresnel lens to focus light, along with some experiments.
Another short, fun one on how fast an electron and electricity move down a wire.
And for variety, how to make a portable crystal radio in a pizza box.
And don't forget to subscribe if you like these videos,
or give a thumbs up or leave a question or comment below.
See you soon!