Fast and Easy Science Fair Projects: Whirring Button

Torque: Changing the direction of the force

Purpose: Learning about torque and changing the direction of a force. A force pulling outward can be changed into a force at a 90-degree angle and it made to do work, causing a button on a string to spin.

Overview: A force can push or pull an object along a straight line. When a force is used to rotate, or turn, an object, physicists have a special name for the force. They call it "torque."

    Torque has a direction associated with it. As your wrist turns a screwdriver clockwise, the force rotates the screw forward into the wood. The torque, or force, is in a different direction from the turning force applied by your wrist. The same is true when a wrench is used to turn a nut on a bolt.

Hypothesis: A change in the length of the string used to cause a button to spin will cause a change in the rate of the rotating button.

You need:

• Ruler
• Scissors
• 2 identical large flat buttons, two or four holes
• Cotton thread
• A friend

Procedure: Loop a piece of cotton thread through a hole in a larger button, and then back through another hole. Cut the thread to a length of 2 feet and then tie the ends together.

     In the same way, loop a piece of cotton thread through an identical button, but cut the length of this piece of thread to 4 feet, and then tie the ends together.

     Hold the looped thread between two hands, moving the button to the middle of the thread. Move your hands together so that the button hangs down, and use a circular motion with your hands to swing the button around and around, winding up the thread until it has wrapped around many, many times. Have a friend hold the second button and longer string, and wind the thread in a similar way, giving it the same number of turns as you do. Note: If your flat buttons have four holes, instead of two, you can place the thread through two diagonal holes, as shown.

     At the same time, both you and your friend pull outward with each hand, and the thread will begin to unwrap, causing the buttons to spin. The outward pulling force of your hands is being changed into the rotating motion of the button.

     The mass of the buttons and the number of winding turns was held Constant, and the length of the string was the Variable. We are "assuming" that the force pulling outward on both button devices is equal. Repeat the test, exchanging whirring buttons.

     Does one device spin faster than the other? Do the spinning buttons set up vibrations in the air causing a tone that is audible - you can hear it? If so, is the pitch higher on one than the other? Is the higher pitch coming from the button that is rotating faster?

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: 1. Experiment using different threads: does string or monofilament line (fishing line) work better or worse in rotating a button? What effect does changing the size of the button have on the speed of rotation?

2. Can you think of other places in our daily lives where torque force if is used?

     Thanks for reading this one! Hope you liked it! This is my 41st hub on Fast and Fair Science Fair Projects. This one is extremely easy, useful and fun! I'm sure most of you all out there, enjoyed reading and trying out this one, especially kids! If you want more on Fast and Easy Science Fair Projects, you can try my other Hubs on the same topic. Here are five of my Latest Hubs onFast and Easy Science Fair Projects for you: