water

Coffee Rings

I have been doing some house cleaning. In cleaning the counters, I noticed a coffee spill that had dried. It had formed a dark ring, with almost no coffee stain in the center. This reminded me of an article that I have read on the science behind coffee rings, giving me the idea for this experiment.

Clear Ice

This experiment is the result of my forgetfulness. I took a tray of ice cubes out of the freezer, used half the cubes and then forgot to put the tray back in the freezer. When I remembered, the cubes were half melted. Only the centers of the cubes were left, and that ice was very cloudy.

Cat Lapping

This experiment comes from a recent event in the science news. Researches have discovered that cats drink in a very different way from dogs and other mammals. Now you might think that things like this had been completely explored decades or even centuries ago, but high speed photography has shown us things that we did not suspect before.

Capillary Filter

One of the interesting things at St. Augustine, Florida's Oldest House is a large stone bowl with a bucket underneath. The stone bowl is half full of muddy water and there is a slow, steady drip of water from the bottom of the bowl to the bucket. Although the water in the bowl is a bit muddy, the water in the bucket is clear. Why?

Can Water Float?

There are many things that will float on water: pieces of wood, wax, Styrofoam, and many other things. They float because they are less dense than the water. Now for the question. Can water float on water? Is there a way to make water less dense?

Breathing Hot and Cold

One of the most common questions that I get is where do I get the ideas for these experiments. Some are old classics that I try to give a new angle. Others are the result of questions sent to me by subscribers. Some of the ones that I like the best are the ones that just pop up, seemingly out of nowhere. This is one of those. It also comes with its own story, which makes it even better.

The story is one of Aesop's fables. If you have never read any of these, go read some. It is well worth the time.

A Cool Experiment

This experiment is one that you can try the next time you take a bath. Have you ever noticed that you feel cold after a hot bath? Actually, there is more than one reason that you could feel chilled when you get out of the tub. If the water was very warm, then the air will feel cooler by comparison, but even if the water was cool and the air was warm, you could still feel a chill.

75% Water

When you read that 75% of the Earth's surface is covered by water, what does it really mean? The answer goes far beyond just a simple fact. As with many topics in science, the deeper you go, the more you find.

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