Rafed English
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By Brenda Pepper

When the Pressure's on, ice can get a grip

For this activity you need a thin strong wire about two feet long. You can find a good one by carefully unraveling a strand from the bundle of thin wires used to make a thicker wire for hanging up a picture frame.

Using this wire and two sticks or pencils, make a one-foot-long wire with a handle at each end. To do it, wind one end of the wire around one stick. Then twist the short end of the wire around the longer end to hold it tightly to the pencil. Repeat these steps to attach the opposite end of the wire to the other stick.

Place an ice cube on top of a tin can. Holding one of the pencils in each hand, press the wire down across the top of the ice cube.

Now comes the only tricky part. You must keep pressing down steadily and firmly—but not so hard that you break the wire. Slowly, the wire will sink into the ice.

It is strange to think that you can cut into ice with a wire. But if you look carefully, you will see that you are not cutting the ice cube into two pieces. The wire ends up threaded right through the ice.

How It Works
Like heat, pressure can prevent water from freezing into ice. Pressure can also melt ice.

If you force a fine wire down hard enough against ice, the pressure underneath the wire can be great enough to melt the ice. As the wire sinks, the water freezes again above the wire.

A thick wire doesn’t work. A person would have to press down very hard to create enough pressure under a large wire.

To create an interesting effect, use ten-pound nylon fishing line instead of wire. Fishing line is harder to press into the ice, but it can be more fun because the fishing line is almost invisible in dim light.