Stirring Sand

I ran across the idea for this week's experiment (which is really more of a challenge), while researching another question. The more I thought about it, the more I liked it. It involves the unusual behavior of sand in a glass of water.

Newton's Laws

This time we will investigate Newton's laws of motion. While Galileo laid the foundations for them, Newton was the one that put them into the form that we know them today.

More Fish in a Bucket

Last time I left you with a question. We were imagining fish swimming in a container of water. When I was a child, I was told that you could put the container on a scale, and as long as the fish did not touch the sides or bottom; you would only be weighing the water.

We substituted a brick for the fish, and found that if we lowered it into the water, the scale went up enough to equal the weight of the water it displaced. Then we placed it on the bottom, and found that the scale went up to equal the full weight of the brick.

Fish in a Bucket

This week's experiment goes back to fishing trips from my childhood. As we caught fish, we put them into a large tub of water. I loved watching them swim around and around. I was told that if you weighed the tub, that it would not register the weight of the fish, unless they touched the sides or bottom of the tub. Was that right? Let's find out.