Catapults
When you fire a ball through the air, it moves both vertically and horizontally (up and out). When you toss it upwards, you store the (moving) kinetic energy as potential energy, which transfers back to kinetic when it comes whizzing back down. If you throw it only outwards, the energy is completely lost due to friction.
The higher you pitch a ball upwards, the more energy you store in it. Instead of breaking our arms trying to toss balls into the air, let’s make a simple machine that will do it for us. This catapult uses elastic kinetic energy stored in the rubber band to launch the ball skyward.
Here’s what you need:
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This was the BEST project ever!!! Love it!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Yes I do mean K’nex
Awesome! I love science too!! So glad you were thinking resourcefully! Send me a picture and I can post it to the website. Do you mean K’NEX?
Hello,I tried the advansed catapult, but I didn’ have tounge depresors, so I used Kenecks instead; And it worked!!!
I LOVE e-sceince,
P.S.I’m Merry’s daughter Anna.
Try more hot glue?
I can not get the clothes pin to stay on. Abbi.
Very cool, we will have to make that
This was awesome!!!! I made one big catapult and two small ones! So there was one on either side of the big one!
A ping pong ball has been flying across our living room all afternoon! We used 7 small Popsicles, 2 tongue depressors and several rubber bands for our fun catapult. We are certainly looking forward to trying another experiment tomorrow. Thanks Aurora
Great idea! I bet it looked great.
I found a box of 300 tongue depressors for only $4 on sale at Michael’s or JoAnn’s craft store – you can try there if you need to. The ones in smaller sets (less than 50 per pack) seem to be really expensive. And any rubber bands will work, as you found out.
my daughter made the frame out of plastic knives and instead of normal rubber bands she used hair ties. That is MUCH cheaper than 8 dollar toung depressers and 3 dollar rubber bands.
COOL!!!!!!!!!!
Anything slightly bendy and about that size will work.
Great Video. Is there anything you can substitute for the popsicle sticks?
AWSOME!!!
this is awsome
maybe on facebook
-Caleb
Sounds like fun – send a photo!
I bet if you added two round rods instead of seven popsicle sticks you could add wheels and make mobile.
-Caleb
it is cool
In the video I used hot glue, but if this doesn’t work, try epoxy (the 5-minute type).
What kind of glue did you use? We tried super glue and hot glue, and the bottle cap would fly off after a few shots.
You can use any number of rigid objects – in fact, there’s a student hat wrote to me saying he’d made a larger model using old bike tires (the inner tube part that holds air) for the rubber bands, spatulas for the spoon, and large pieces of wood for the frame.
That was cool! Do you have to use popiscle sticks for this experiment or can you use something else?
I made my catapult and it is AWSOME!!! now i am going to make a lego catapult.
My brother LOVES this. He is going to use it for his Legos/Playmoabile.
Holly Thomson:)
Well, it sounds like close to the end of the video when you launched the catapult it broke some glass.
sevy keble