For a catapult, potential energy is stored as elastic energy. This energy results from the force put in as the muscu- lar push or pull needed to stretch, bend, or twist some sort of elastic material that is attached to the throwing arm.
For a trebuchet, the potential energy is gravitational. Catapults: Catapults take advantage of elastic force, involving stretched, compressed, bent, or twisted material. First Law The acceleration produced when a force is applied depends on the mass of the object. Third Law. 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 Leave a Reply Cancel reply Your email address will not be published.
Demonstrate how to load and launch the catapults. Encourage children to try them out. Try adjusting the force you use with the catapults to fire the pompoms different distances into different zones e. Extensions For younger children, set up the fulcrums of several catapults, each in a different position.
Which catapult flings the pompom farther? For older children, challenge them to adjust the location of the fulcrum themselves and see how it affects the distance the load travels.
Hint: Set up the catapult with the fulcrum positioned so that it is least efficient at the start of the exploration to encourage children to adjust it. Theme the target zones, such as water with alligators or castles with guards. Try this activity to find out! Observations and results Did you see your cotton ball fly higher and farther when you pushed you launching stick farther down? When you bend your stick, you load your launching stick up with energy.
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.
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