Physics 1090: Second Labor
We’ve all heard the loud noise that accompanies the flick of a whip or a towel. But have you ever wondered why it makes that noise? Why can such a small motion make a large “crack”? Thanks to the laws of physics, we can find out.
When you look closely at the motion of a bullwhip, your hand moves quickly while holding on to the handle, causing a wave to travel along the whip’s length. Now, the shape of a whip is very thick towards the handle and then it gradually gets thinner until it ends. Because of this structure, when the wave travels down the whip, the whip accelerates. To think about it a little more clearly, as the whip gets smaller in size there is still just as much energy moving through the smaller amount of whip. So, as the wave travels, it is able to accelerate because there isn’t as much material to move. Then, when the wave hits the end, it actually exceeds the speed of sound and the tip generates a sonic boom (or shock wave).
So, why does this work with a towel? Well, when you wrap a towel, it creates the same cylindrical shape as the whip, causing a lot of energy to be pushed through smaller amounts of mass. Although, when a towel is wet, it makes a louder “crack”. This neat experience happens because the towel now has more mass so you have to work a little harder to make it move.
With this little piece of advice, you can cause the whip of your towel to be a little more painful for your unsuspecting victims. If you’d like to Learn more about how to make a whip out of a towel or any other information about the crack of a whip, these cites were very helpful to me while I looked for information and they could be of help to you too:
| Website | Information |
|---|---|
| How to make a "Rat Tail" | This website gives you an effective demostration of a great way to make an efficient whip out of a towel. |
| How to crack a Whip | This website allows its viewers to view a step by step demonstration of how to flick a whip. It also stresses the importance of safety. |
| The Washington Post: Learn to Crack a Whip | This article in the washington post allows you to access three other websites that help you master the art of cracking a whip. |
| Whip Cracking Mystery Explained | This final website held an article that is very helpful at explaining the physics behind cracking a whip. It helped me Gather knowledge to use in my simple, straightforward article. |
| The Flying Circus of Physics | This is not a webpage, however it is a great book that helps to answer the question that I posted and many more. You can find it on ebay, amazon, or in many nearby libraries. it is written by Jearl Walker. |
This information was collected by Rachael Cox on October 26th, 2009