It’s Mangled Messes time again! This month, we took a look at siege engines! I mean, who doesn’t love mini catapults? Sure, technically what we built are probably considered mini mangonels…but it’s still fun.
There is something fascinating about watching a catapult launch it’s projectile, especially when weights and balances are concerned. It really is an art to get just the right amount of balance to get the maximum amount of power. Fascinating.
I started the program by talking about catapults; there are a few different kinds, you know.
•Ballista — Looks (and works) like a crossbow.
— This one includes a lever and sling, and could hurl up to 200 pounds nearly a mile.
— Has a bowl-shaped bucket at the end of a giant arm. The bucket is loaded with whatever is being thrown. (This is the most like what we made).
After this brief introduction to catapults, I showed the kids a video of a trebuchet in action, which is seriously awesome. If you haven’t seen one demonstrated, definitely get out to your nearest Renaissance faire. (Or, you know, hit up the internet.)
Then we set to work. I looked all around the internet for the easiest way to build mini-catapults with kids. The plan from Science Sparks
was what I most closely followed. That was how our catapults looked, anyway.
First, gather your supplies. We started with: 10 popsicle sticks, one popsicle stick with a water bottle cap attached, and 16-18 elastic bands.
Next, we built the base.
To do this, I had the kids connect the Popsicle sticks at right angles, which when repeated, forms a square. (See above)
I had them wrap the elastics around the sticks. It is hard to verbally explain, it takes some fiddling, but you eventually figure it out. Basically, you take one elastic and hook it around one end of one stick. Place a second stick over the first. Wrap the elastic around both sticks, fastening them together, and pulling them tight. To secure, loop the elastic around one of the sticks. (It is really more of a show motion than a tell motion.) It ends up looking like the image below. Make sure you change the direction that you wrap the elastic half way through to evenly distribute the pull from the elastic (so it makes an x and keeps the sticks more securely together. Trust me, it really works).
After the base was made, we build the sides. This is the same premise of connecting sticks together, except the angle is less than 90 degrees.
We then connected the two sides to the base we already built.
This is the tricky part, though it uses the same elastic attaching principles that we’ve been using the whole time. It’s just that the actually attaching makes it awkward. But, stick with it. At this point, you may notice that the catapult is a bit wobbly, or a little off kilter. That’s ok. It’s personality. Roll with it.
Next, we attached the stabilizing section, which goes across the two side pieces.
A popsicle stick sits in the crook that each of the sides makes. This crossbar section is what the ‘throwing’ arm runs into and what helps toss the projectile out of the bottle cap.
After that, we created the throwing arm. Using the same principals of popsicle stick attachment as before. You will notice the extra elastic holding the cap on the stick….mine came off. I had to reglue.
Finally, we attached the throwing arm to the sides of the catapult to finish our structure! There is no set way to do this, just make sure that the cap doesn’t snag on the cross-arm. Otherwise your thrown item will be a little stunted.
There you have it! These are a lot of fun to make. Though it takes some time and effort. The kids had a blast, even though they were initially frustrated. But, once they got it, they really got it.
While we were building, we talked a little bit about the stored energy in the elastic bands and how that would launch our mini marshmallows. All-in-all, we had a lot of fun. And that’s what this is all about.