# Fast and Easy Science Fair Projects: Man on a Tight Rope

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2 chairs
Scissors
a small piece of paper
Pencil

Wave Motion

Purpose: Show that energy can travel along a string and do work at the other end.

Overview: Energy can travel in the form of a wave. An uncrested wave in the ocean is energy in motion. The water molecules do not travel along with the wave. That is why a boat will bob up and down when a wave goes by but does not move sideways. Surfers ride the energy if a wave, but not the actual moving water. The water only moves in a circle, but the wave energy travels forward. If you tie one end of a rope to a fixed object, such as a fence post, pull the rope tight, and then give your end a quick snap up and down, with a fast wrist movement, you will see a wave-like motion travel motion travel along the rope to the fixed end. That is wave energy moving along the rope, but any spot on the rope only moves up and down. You can see this easily by making colored markings along the rope and watching them bob up and down. Now, let's track the energy.

You need:

• length of string
• 2 chairs
• scissors
• small piece of paper
• pencil
Procedure: Set two chairs about 4 feet (125 cm) apart. Tie a string tightly from the back of one to the other. Cut a small string tightly from the back of one to the other. Cut a small square piece of paper and fold over one-quarter of it to act as a hook. Hang the piece of paper onto the string near one end by the fold in the paper. Near the other end, hit the string hard with a pencil. You have put energy into the string by making it move up and down. Does the energy travel along the string and flip the piece of paper off the string at the other end?
Results and conclusion: Write down the results of your experiment. Come to a conclusion as to whether or not your hypothesis was correct.
Something more: Make a colored mark in the middle of a long piece of rope, such as a jump rope or clothes line. Hold one end of the rope and have a friend hold the other. Wave your arm with the rope up and then down, have your friend do the same but in the opposite direction: when you go up, he goes down. It is possible to synchronize or time, both your moments so that the mark in the middle of the rope will not move up or down?