Balancing Act: A 60 Second STEM Investigation
Cut a shape out of the poster board. In our video, we used a triangle but any shape will work including figures like birds.
Try to balance the shape on your finger. It should fall.
Place two or more clothespins on the shape and try to balance it on your finger.
Move the clothespins around until the shape is able to balance.
Make it an experiment:
Try to explore what happens if you add more clothespins. Does the balance point stay the same or does it change?
With this investigation, we are exploring center of mass. When scientists are discussing center of mass they are talking about the point where the masses, or weights, cancel out. Another way to think about this might be as a balance point. If you imagine two people on a seesaw who have the same weight then their center of mass is where the fulcrum is (where the seesaw tips up and down).
But if one of the people is heavier, then the center of mass is closer to the person who is heavier and the seesaw won’t work until they move. This is exactly what is happening with the clothespins!
As we move around the clothespins, we are changing where most of the mass is which changes the center of mass. When the get the clothespins into the right spot, they create a balance point that allows the shape to balance on our fingers just like a seesaw.
Click here to watch Hannah from Shoestring Science explain and complete this investigation