Introduction: Building the Collapsible Catapult

Today we will teach you how to make a collapsible catapult out of household materials.

Step 1: Materials Required

To build the catapult you will need:

6 Wooden Pencils

A variety of rubber bands with differing thickness and size

A water bottle

A knife

Rubber Cement (Optional)

Step 2: Beginning the Base

First we will start making the base of the catapult.

Begin by banding 3 pencils together. The band should sit just under an inch below the ferrule (metal part) on each pencil.

Step 3: Completing the Base

Arrange the 3 pencils into a line. Now band the two pencils on the outside edges together; this should be easier by pushing the top ends of the pencils behind the top end of the inner pencil.

We recommend using a different colored rubber band for this if possible; this will make identifying the orientation of the catapult easier.

Step 4: Making the Launch Arm

Band 3 pencils together as pictured below. The extended pencil should have approximately 2 inches of overlap with the other two pencils. Use two rubber bands to make sure that this pencil is securely attached.

Step 5: Making the Basket

Remember the water bottle from the requirements? You will need to cut the bottom of the water bottle off to create a basket for the catapult. For our catapult, we cut the basket to be around 2 inches deep.

You will need to cut two holes through sides of the basket near the base. The holes should be on opposite sides of the basket. Make these holes large enough to allow a pencil to fit through.

Step 6: Attaching and Securing the Basket

Slide the basket down into the extended pencil on the launch arm. Then, tie a thick rubber band tightly around the top of the pencil. This will act as a stopper to prevent the basket from sliding off when firing.

You may apply rubber cement to the basket where it contacts the pencil; this will help reinforce the basket so that it does not twist when in use. This is not a mandatory step.

Step 7: Attaching the Firing Arm to the Base

Tie a thick rubber band about 2 inches up from the bottom of the middle pencil on the base we created earlier (this will be the pencil with one rubber band around it, not two). Now, on this same pencil, band the bottom of the firing arm below the thick rubber band we just attached so that the firing arm is pointing straight up. This band should rest at the bottom of the ferrule of the pencils on the firing arm.

Step 8: Adding the Tension Band

Finally we will add the tension band to the catapult. Stretch the band down over the basket and place the band around the firing arm and the entire base; the band should rest just below the band that hold the base together.

Experiment with the thickness and size of this band; this will adjust the power of the catapult.

Step 9: Using the Catapult

With the catapult fully build, now comes the fun part. First Expand the catapult's legs by pushing the middle pencil of the base between the other two legs of the base.

Next, cup one hand around the base so that you have your palm in contact with the middle leg, your thumb in contact with one leg, and your fingers in contact with another leg.

Finally, using your free hand, pull back on the firing arm and release!

Now that you know how to operate the catapult, just load up the basket and launch some stuff!

Comments

author
amberrayh made it! (author)2015-04-06

Great job on your first Instructable! Does the catapult shoot well? Do you have a video?

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