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Explore Centripetal Force

Explore centripetal force using a pail, jump rope, and water! This activity is accessible to all age groups depending how deep you want to dive in. It may take a couple of tries to get the "swing" of things. 

1. Grab a pail, jump rope and water! If you don't have these items a cup or other vessel that can be attached to a string will do! 
2. Thread the jump rope through the handle of the pail so that there about a forearms length between you and the pail.  
3. Fill the pail 1/2 way with water! 
4. Hold your arm out in front of you and spin your arm in a circular motion like you are drawing a circle around your upper torso. Repeat the same circular motion this time with the pail and water in hand! Once you get the "swing" of things you should be able to lasso the water-filled pail around your head without spilling a drop! 

What's Happening? 

Sometimes objects move in a curved or circular path. While an object moves due to velocity, or its speed in a certain direction, centripetal force is the force that keeps the object moving in a circular path. It does this by pulling an object toward the center of a circle. Keep in mind, there is always some other force that attaches the object to the center of the circle, like a tether.

A tether is something that attaches a moving object to another, like a dog's leash or a yo-yo's string, to keep movement contained to a certain area. This is an image of a game called tether ball. The string attaching the ball to the pole is the tether. The ball moves in a circular motion due to centripetal force and the tether, which keeps the ball connected to the pole, pulling to the center.

For centripetal force, the tether might be an actual object, like a chain, or it might be a force, like gravity, that acts like a tether.

So, you could call centripetal force a central pulling force. It's important to know that the object keeps moving in a circle for as long as the centripetal force continues and no other forces affect it.

One other important piece is inertia, which is a resistance to change. Inertia will try to keep objects moving in a straight-line path. Objects try to move in a straight path. However, when you add another force, like centripetal force, you can make it move in another way, in this case, in a circle!


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