When the spoon is pushed down, the load pom pom or bouncy ball travels upward- in the opposite direction equal to the force applied on it.
Third Law of Action-Reaction. A catapult is a simple machine that has been around for ages. Have your kids dig up a little history and research when the first catapults were invented and used! Hint; check out the 17th century! Leave a Reply Cancel reply Your email address will not be published. Save my name, email, and website in this browser for the next time I comment. This site uses Akismet to reduce spam. Learn how your comment data is processed. Skip to content Image source: Pixabay.
When you let go, this energy is released and converted to energy of motion. Most of this energy transfers to the missile, which shoots through the air. Pushing the stick down farther takes more effort from you. Maybe you felt you needed to exert more force or work harder to bend the stick farther.
Bending farther means more elastic potential energy gets stored in the stick, and when you let go, all this potential energy is converted into energy of motion, so the missile flies through the air at a higher speed. In the case of your catapult, the missile probably flew higher and farther. Moving the stack of six sticks closer to the launching cup makes the launching stick lie flatter. This results in a missile aimed more upward than forward.
Pushing your six sticks the other direction creates a greater angle between the launching stick and the base. This helps you aim the missile forward. Bombs Away! This activity brought to you in partnership with Science Buddies. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. Key concepts Physics Engineering Elastic potential energy Projectile motion Introduction Catapults were mighty handy for pirates in the golden age of piracy during the 17th century.
Materials Eight craft sticks popsicle sticks Four or five sturdy rubber bands Glue Plastic bottle cap to hold a cotton ball Cotton ball If you do not have any available, you can make a small ball by crumbling some paper. Small open area One square meter will do. It should be a sturdy, flat surface such as a table or floor.
Preparation Note: The simple catapult described in this project is safe when used with a cotton ball. Shooting hard objects or using other homemade catapults can be dangerous. Make sure any objects you launch are soft and light so as not to harm anyone or cause any damage to objects around you. Take six craft sticks, stack them one on top of the other. Secure these sticks together by wrapping rubber bands around both ends of the stack. You will anchor the launching stick to this stack, as described in the next step.
To add the launching stick take one stick and attach it perpendicular to the stack you just made, around the middle, so you get a cross shape. You can do this with one or two rubber bands that are crossed in an X over the sticks.
A catapult is a simple machine. As the arm is pressed down in ours, tension builds and energy is stored. When the arm is released, the elastic energy think slingshot is converted to kinetic energy — the energy of motion. When an object is placed in the bottle cap, it will move at the same speed as the arm and lid. The catapult works when the potential energy stored in a stretched rubber band is converted to kinetic energy when it snaps back to its loose shape, moving the catapult arm—and the projectile!
The kinetic energy of the catapult will give the projectile a force moving up and away from the catapult.
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