Science Experiment: Centripetal Force – Tornado in a Bottle

Science Experiment: Centripetal Force – Tornado in a Bottle

More Science Experiments

Can You Feel the Force?


Centripetal force is what makes an object move in a spiral pattern when it is travelling in a circle, the force that pulls a thing toward the center of the rotation, like a penny in a funnel shaped srptornadowishing well or 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”.

Today, we are going to learn about how liquid and air behave when they are moving in spiral pattern. 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. You can demonstrate this at home too.

What You Need:

  • 2 Liter Soda Bottles
  • Duct Tape
  • Water
  • Food Coloring (Optional)
  • Click on a website below for directions on how to put this demonstration together.

The tornado in the bottle looks a lot like the water draining out of the bathtub. When liquids pour they make a spiral pattern around a center. This is called a vortex. Gravity is pulling the liquid down toward the hole while the force of the pouring water is rotating around a center point…the middle of the drain or the neck of the liter bottle.

Websites, Activities, Printables & Databases:

Science in Context: Centripetal Force is a database you can use in any IndyPL Library Branch or at home. Login using your IndyPL library card number. The Science in Context database will show you articles, images and videos to help you learn about centripetal force.​



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.



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Did You Know ScienceDIY ScienceExplore Forces and MotionForces Physical Science for KidsForcesHow to Build a Tornado in a BottleHow to Design the World's Best Roller CoasterTornadoesTornadoesWhen the Sky Breaks
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4 Responses »

  1. well, on a force diagram centripetal force isn’t supposed to be drawn. the way it works is that acceleration is pointed inwards and velocity is pointed tangent. the centripetal force is a result. it is actually a force that goes inwards, not in circles. you did define that correctly. i’m pretty sure this is okay. the CENTRIFUGAL force, on another hand, does not exist.

  2. Bad Science. There is no such thing as Centripetal Force. There are a combination of other forces at work which give the ILLUSION that there is another force at work.

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