How and why can you cut ice in half with a wire?

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.

ExampleFor example, ice-skates. All of your weight

rests on the two thin steel blades of the skates. This great pressure causes the ice directly under the blade to melt. So the

blade slips easily across the ice on a very thin layer of water. As soon as the skate moves

away, the surrounding ice freezes that water again. If you tried to use ice-skates on a concrete skating rink, you wouldn’t get

anywhere at all.

Materials you need to do it1. 2 pencils

2. A thin wire3. One ice cube4. A bowl or can

5. Somewhere to conduct the activity

How to do it1. Freeze some water in an ice cube tray.

2. Put one ice cube on something like a can or bottom of a plastic bowl.

3. Tie two pencils to each end of a thin wire.4. hold each end of the wire, or pencils, in your

hand and press the wire down onto the ice cube.

5. Continue to press down until the wire is through the ice cube (this could take a little

while, depending on how frozen it is).

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