Magic and Mayhem

Apologies for the title. I couldn’t resist!

I gave some kids some leftover “jewels” from Annalee’s pirate and princess birthday party today. Right away Victoria tried making rainbows around the room with a clear one and Jack and I tried to catch them. Having a full blown case of ECD (Educational Compulsive Disorder), I had to go search for prism-y stuff on the net!

Here’s some cool stuff I found:

National Geographic tells how to make a rainbow in a dark room with a glass jar, a flashlight and a mirror.

This great site explains prism shapes in a colorful, easy to understand way.

Here’s a bit of trivia about prisms:

1) What is the difference between reflection and refraction?

Reflection is when light is bounced back at an object. Refraction is when light is bent as it travels through a different medium, but continues in the same general direction.

2) Is the index of refraction the same for water and ice? If not, what is the difference?

The index of refraction for water 1.33 and ice is 1.31. The optical density of ice is less than that of water. Light travels through ice faster than it travels through water.

And more info from the same site:

How are rainbows made?

Rainbows are caused by another aspect of refraction called dispersion. Light waves of different frequencies (colors) bend different amounts. In most cases, this is not noticeable, but prisms make use of this to spread out the spectrum so we can see all of the colors. Violet light bends the most, with each color bending a little less up to red, which bends the least.

If light is bent when it passes through glass, is everything we see through a glass window actually in a different spot?

Light is bent when passing through a transparent material. What happens when you look out a window? Does the bending of light mean that nothing is where it appears to be?

Refraction does when you look out a window, but the effects of the bent light is canceled out. A clear glass has two surfaces that the light passes through - the inside surface of the glass and the outside surface of the glass. When the light passes through the inside surface of the glass the path is bent in one direction and when the light passes back out through the outside surface of the glass it is bent in the other direction. They cancel each other out and there is no noticeable effect from refraction.

And here’s a free demo of a game about lasers, angles and prisms. We haven’t tried it yet but it looks cool.

We also have a Magic School Bus book about the subject that we’re going to read again.

I’m off to catch some more rainbows with the kids and play with prisms. See you soon….