# Fast and Easy Science Fair Projects: Whirring Button

Updated on December 30, 2019
Click thumbnail to view full-size

## 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?

6

45

1

26

17

40

## Comments

0 of 8192 characters used
• AUTHOR

Don Ship

10 years ago

Thanks a bunch, Jackavc! I'm really glad to hear that! I've been trying to write as many Science Projects as possible here. I won't be writing too many here after though. I may do just 3-5 more! There hubs are all doing great for me, some of them totally are! Your comment just made my day! Hope you are having a nice day too. Thanks again, mate! :)

• jackavc

10 years ago from Australia

Well done Don my children are really enjoying these hubs. They keep asking me for more projects to do. I think you are on to a winner here. Hope these hubs are going well for you.

working