Balancing Forces
Have science fun as a family! Complete activities with parental supervision.
Materials:
- Sticks, skewers and/or straws
- String
- Scissors
- Hole punch or thumbtack
- Cardboard or cardstock
- Markers (optional)
Procedure
- Cut several objects out of cardboard/cardstock. Use your imagination! Decorate your objects if desired.
- Poke a hole in the top of each object with a hole punch or with whatever you have in the house- a thumbtack, pin, scissors, etc (adults – this is all you!).
- Tie a piece of string to the middle of a stick. This is how your mobile will hang.
- Using string, tie one object to the far end of one stick. What happens?
- Try to balance your stick! It is balanced when it is horizontal. Add objects to the other side of the stick or move string down the stick—the string doesn’t have to be in the middle of the stick.
- Now, tie another stick below the first and add objects, moving them until your second stick is balanced.
- Keep going! Your mobile can have two, three, or more sticks to make a beautiful hanging work of art.
- What happened when you added objects? How were you able to get each stick to be horizontal?
- Be sure to take a picture or video to share in the Facebook comments on the Buffalo Museum of Science or Tifft Nature Preserve pages!
What’s it all about?
Think of a see saw. If two people of equal masses are sitting on either side, the see saw will be flat and balanced. But when the masses on each side are different, the see saw will not be in balance.
This is due to forces— the pushes or pulls on an object. It’s the force that pushes is down towards the Earth so we don’t float away.
Everything has a center of gravity—a point where the weight is evenly distributed. In a ball, the center of gravity is right in the center of the ball. But in the case of these mobiles, where that center is gets complicated. As more things are added, that center shifts.
Try It!
This experiment just called for cardboard, but is there anything else you could add?
