Catapults

My Safety Catapults: Have studnets put mass on a catapult to determine Force. Have students determine the acceleration of two different sand bags shot from a catapult. ..................................................... What is Newton’s second law of motion? Why is Newton’s second law of motion important if you want to catapult an object a certain distance? How will the mass of the projectile affect the distance it travels when launched by a catapult? Note to self: I can't find anything on my Catapult activity. Website or documents. I must have lead them through the activity by demonstrating it. ............................................................. Mass X Acceleration dude to gravity = elastic force produced by the catapult. Mass of a sand bag X elastic force of catapult = the acceleration of the sand bag. Student see how mass effects acceleration and relates it to calculated numbers. ............................................................... Newton’s second law was the basis of the activity. Force = Mass X Acceleration.

Objective: See the effect of mass on acceleration. (See how mass affects the speed and distance of a sand bag. How will the acceleration of a big and small sand bag be different and by how much? (Student first made their sand bags) How will acceleration affect how far a sand bag flies?

First, the acceleration due to gravity was used to determine the elastic force produced by the elastic band in Newtons. Students used a bread bag to hold weights. They balanced the weights on the end of the catapults arm. The students determined the minimum mass to hold the catapults arm down. This mass was converted to kilograms. This mass times the acceleration of gravity equals the maximum elastic force the catapult could produce. (Elastic potential energy and potential energy of the weighs are balanced to determine elastic force capacity of the catapult.) .................................... Make force meter to test catapult force. https://www.youtube.com/watch?v=U3thDj-B6gM

Catapult Challenge

Give students this and tell them to make a catapult that will project a marshmallow two meters.

• 9 popsicle sticks • 5 rubber bands • A (safe) projectile of your choice

[] [] http://www.scholastic.com/teachers/sites/default/files/posts/u133/pdfs/catapult_challenge.pdf []

http://rlptqf.blog.com/2011/10/29/how-to-build-a-medieval-ballista/

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 **Make a Catapult ** This catapult design is uber simple and requires no power tools (unless you consider a hot glue gun one).

You'll need 10 jumbo wooden craft sticks, hot glue, four rubber bands, and a recycled plastic cap.

1. Stack eight sticks and wrap a rubber band around each end. Then, stack the remaining two sticks and wrap another rubber band around one of the ends.

2. Separate the two sticks hinged together with one rubber band and slide the stack in-between.

3. Add the last rubber band by weaving it in and around the point where the sticks meet.

4. Apply a dot of hot glue and attach the plastic cap. **Make it a Math Game! ** You'll need something to shoot in the catapult. We used pom pom balls.

Grab four disposal plates and label them with numbers. I used 5, 10, 15, and 20. Use your child's ability to gauge what numbers are appropriate. When playing this with my preschooler by himself, I will just use one plate so he can count by ones how many pom poms hit the target.

Now lay out the plates and load the catapult with a pom pom. Push down on the pom pom-filled cap, release, and watch it fly! Have kids add their scores together. 