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Why the Tricks Work

The Disappearing Liquid

Think about mixing a liter of marbles and a liter of sand. The sand would fill in some of the spaces among the marbles. (The marbles would also fill in some of the spaces among the grains of sand.) So, the volume of the mixture would be less than 2 L. This is similar to what happens in this trick.

Rubbing alcohol and water actually dissolve in each other. That is, they mix together at the molecular level. Molecules of each liquid move into spaces among molecules of the other liquid. So, none of the liquid really "disappeared." The close packing of the molecules of the two liquids reduced the volume of the combined liquids.

The Great Tissue Bust

When the broomstick is pushed into the tube, the force applied to the broomstick is not transferred directly to the tissue. It is transferred to the salt, which has many spaces among its grains. Much of the force applied to the broomstick is "used up" in pushing the grains of salt closer together and against the sides of the tube. Only a small fraction of the force actually reaches the tissue. This force is too small to break the tissue.


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