Have you ever put a coin in one of those wishing wells that is shaped like a giant funnel? The coin rolls around and around the sides of the funnel in smaller and smaller circles until it goes down the hole in the middle of the well. That coin is demonstrating centripetal force. Centripetal force is the force that pulls a thing toward the center of rotation….like the little whirlpool that forms when you drain the bathtub or like the Zinga water slide at Holiday World! Why IS that water slide called Zinga? Because in Swahili Zinga means “to move in a circular motion”. Lots of amusement park rides work because of the laws of physics. You can do the activity hex nut balloon to demonstrate centripetal force.
What You Need
- Hex Nut
Blow up a large balloon. Before you close the balloon, put a hex nut in it and then tie the end of the balloon closed. Hold the balloon between your hands and move it in a circular motion until the hex nut starts to roll around the inside of the balloon. Now stop moving the balloon and watch what happens to the hex nut. What you are seeing is centripetal force. The hex nut is on a circular path inside the balloon. Things that are moving in a curved or circular motion will slowly move toward the center of the circle, in this case, the bottom of the balloon. What sound does the hex nut make? How about a penny? A marble? Try them all and see how they behave the same or differently.
Websites, Activities & Printables
- Video: Steve Spangler Science – Screaming Balloons
- PBS Kids: Fetch Whaohler Coaster
- Funderstanding Roller Coaster Demonstration
- Roller Coaster Physics: Design a Roller Coaster
You can also ask a math and science expert for homework help by calling the Ask Rose Homework Hotline. They provide FREE math and science homework help to Indiana students in grades 6-12.
e-Books and Audiobooks
Use your indyPL Library Card to check out books about Science Experiments at any of our locations, or check out science experiment e-books and audiobooks from OverDrive Kids right to your device! If you have never used OverDrive before, you can learn how to use it for both e-books and audiobooks.
Need more help? Ask a Library staff member at any of our locations or call, text or email Ask-a-Librarian. Additionally, the Tinker Station helpline at (317) 275-4500 is also available. It is staffed by device experts who can answer questions about how to read, watch and listen on a PC, tablet or phone.
Move It! How Things Roll, Slide & Fly – the Science of Forces and Motion
Learn about the physics basics that explain how forces move things on earth. Speed, acceleration, push, pull, inertia, and friction are just some of the concepts covered. Find out the basics that explain how your bicycle works as well as the creative use of these same physics principles that result in the thrill of roller coasters.