Mini Siege Engines

FeaturedContest Winner
Picture of Mini Siege Engines
Ah catapults - a classic and exciting engineering project that introduces students to some fundamental ideas in physics and engineering. Stored energy, trajectory, the value of density in projectiles, and of course firing stuff across the room!

Lesson Plan:

Grade range: 3-5
Prep: 1/5
Setup: 2/5
Cleanup: 1/5

Prep: None
Setup: Set up glue guns, designate a firing area

Start-of-class lecture for all projects
  • Demonstrate the project
  • Explain how rubberbands are used to store and release energy
  • Explain how trusses are used to create simple but sturdy frames
  • Show step-by-step how to build the mini siege engine
  • Discuss safety
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Step 1: Simple Catapult

Picture of Simple Catapult
This catapult is a very easy project to teach! I have had groups of children in grades 1-5 make this. The finished catapult feels very study and it can fire up to 30' from a tabletop.

The easiest way to show kids how to build this is by taking the the catapult apart into it's two components: the base + support, and the catapult arm. Point out the key features of the design like where the hinge will be, how the cubes with hinges are not connected with sticks, and how the cubes on the base are connected on three sides to make the base sturdy. Next, show the students how to assemble the catapult and attach the rubberbands - students in grades 1-3 typically need help with this.

To fire:
  • Load the projectile
  • Firmly hold down the front of the catapult
  • Pinch the cube under the basket and pull down, then release
kurtwied4 months ago
all your projects are awesome!!:) i'm going to show my friends. where do you get the cubes you use? do you get them in large or small amounts?
WYE_Lance (author)  kurtwied4 months ago
Thank you! You can buy the cubes here:
To get corks, do you just save them from bottles or do you by them en masse from somewhere?
i buy them at hobby lobby.
kurtwied4 months ago
this is awesome!
kevmcd11 months ago
Quite simply splendid!
yapoyo1 year ago
I like this very much. How can I make this without the craft cubes? Are they really necessary?

WYE_Lance (author)  yapoyo1 year ago
The cubes aren't necessary - I use them because it's what I use in all of my projects. I don't know what you have access to, so if I were you I'd rummage around my home for materials or visit a craft or hardware store. Good luck!
ynze1 year ago
And again congrats for being a winner in the Education Contest! Great project!
WYE_Lance (author)  ynze1 year ago
Thanks! I am so psyched!!
poofrabbit1 year ago
Congratulations on being a winner in the Big and Small contest!
WYE_Lance (author)  poofrabbit1 year ago
Why thank you - you're quite gracious. I've seen your positive feedback all over the site. Keep it up, and good luck in future contests :)
Awe you are so kind! I was excited to read you are in talks with instructables to sell a kit of one or more of your instructables! I think that is wonderful!! Your partner in education, poofrabbit
person%1 year ago

i used to enjoy making shooting thingies, i once made a thing similar to the skewer shooter, but it was aluminum (from cans) and it used a thick red rubber band and it can shoot sticks and pencils as well, but it wasn't as strong. i used to sell them as well. they don't reload very quickly and is not very accurate, so i use it close range. i also made a lot of similar shooters, one of then is a sliding one for extra power, and one that is about 2-3 centimetres long for hiding it from teachers.

i still think that the ones i just said do too much damage and gets me into a lot of trouble, so now i making paper wasp shooters.
rimar20001 year ago
Very fun for kids!
snoo1 year ago
this will be great for food fights!!!!!!!
batonas1 year ago
I love all your project, they are simple, afordable for anyone and great for children physic education, way more fun than reading a boreing book.
Keep up the good work.
P.S. you could sell diy sets for these project I think people would be glad to buy it.
WYE_Lance (author)  batonas1 year ago
Wow, thanks for the kind words :) I've been talking with the Instructables HQ about selling the rubberband helicopters as kits - hopefully we'll see them in the store soon!

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