Today marks the start of a new series here on Miss Sky's Classroom: STEM How To! This will be a series of posts relating to various STEM Challenges available in my TPT store, giving the instructions on how to create a basic model that satisfies the challenge requirements. The first model we are going to tackle is popsicle stick catapults!
Materials for one model:
7 popsicle sticks
3 rubber bands
1 plastic spoon
Tape (I used standard scotch tape, but any tape will do)
Step 1:
Stack 5 of the popsicle sticks on top of one another - this stack will become the fulcrum which gives the catapult its firing angle.
Step 2:
Tape both ends of the stack, approximately 1cm from the end. I find it's best to wrap the tape 2-3 times for security so the stack doesn't slip when the pressure is applied.
 |
| The fulcrum is now complete! |
Step 3:
Take the remaining 2 popsicle sticks and tie a rubber band around one end, at least 1cm from the end. This tie must be tight enough to keep the 'arms' together, however, be sure not to tie it so tight that it has minimal elasticity left or it may snap or pop off!
Step 4:
Pull the arms apart just wide enough to wedge the fulcrum part way in. Place the fulcrum so that it is centred across the arms and approximately two-thirds of the way to the rubber band.
Step 5:
This step is (in my opinion) the trickiest! I'm going to do my best to explain my rubber-banding technique used in the above photos, but essentially you can do whatever works to keep the parts together!
Start at the open side of the arms and loop the rubber band around twice. On the second loop twist the rubber band and bring it down so the loop finishes underneath the closed end of the fulcrum, creating a cross much like the one in the third picture. Then create another cross to tighten the elastic. You can repeat the process so you have a cross on the bottom of the catapult, however, this isn't necessary provided you have a band hitting each corner where the fulcrum and arms meet. |
| It should look something like this at the end of step 5! |
Step 6:
Insert the spoon so that it sticks through most (if not all) of the layers of elastic on the top from the previous step.
Step 7:
Tie the final elastic around the spoon and the end of the top arm. This elastic isn't integral to the functioning of the catapult so it needn't be too tight. However, it does give that little bit of added security to ensure the spoon doesn't go flying along with whatever you are launching!
And there you have it! A completed popsicle stick catapult!
If you are interested in using this in your classroom, please head over to my Teachers Pay Teachers store and pick up the Catastrophic Catapult STEM Challenge. This packet has worksheets guiding your students through the engineering process as well as a full lesson plan aligned to the Australian Curriculum!
