# Coins Through a Hole

With a knowledge of the science of topology, you can put a coin through a hole that is smaller that the coin, without tearing the sheet of paper.

# Cartesian Diver

This demonstration is a marvelous way to explore density, why things float and sink, and as a great brain teaser to stimulate critical thinking.

# States of Matter

Most people are familiar with three states of matter: solid, liquid and gas. Actually, if you dig into the world of physics, there are several more, but for now we will only add plasma to the list, and we will look at the first three states before talking about plasma.

## Solid

Things like rocks, wood and ice are solid. Solids stay the same size and shape, no matter what container we put them in.

## Liquid

Things such as alcohol, oil, and water are liquids. They stay the same size, but they change their shape to fit their container.

# Squeezing Matter

This investigation comes from a request made by a teacher. She wanted an easy way to demonstrate how different states of matter react to pressure.

# Cartesian Raisins

One of the fun things about thinking up new science experiments is combining two or more old ideas into one new one. This time, we will combine the Dancing Raisins activity with the Cartesian Diver.

# The Science of Campfires

This experiment comes from my neighbors at the Malibu Creek State Park campground. While taking my morning walk, I heard a lady bragging to her husband that she started the campfire with only one match. That made me think of the fellow that I watched the night before as he poured two bottles of charcoal lighter fluid onto a pile of wood and still failed to get the fire going. He would pour on the liquid and get a huge blaze, which quickly died. How could the heat of one match work better than a gallon of blazing lighter fluid?

# Snow Rollers

I recently presented a session on teaching electricity at the Utah Science Teachers Association Conference. On my way home, I did quite a bit of photography of the snowy landscape, but one roadside slope caught my eye. Driving past, I saw something that I had only seen in books, and a few recent weather articles. Snow rollers! They are usually quite rare, and of the hundreds of snowy road cuts that I passed on the drive home, this was the only one that had them.