In this part of the tutorial we make the swing arm of the catapult. This is where the action happens.

Now tape the rubber band to the three inch popsicle stick as shown by laying it on the stick at the rounded end then wrapping it with tape. Do at least four wraps and make it nice and tight.

Now insert that assembly right into the base of the catapult as shown. It slides tightly between the two pieces that are taped together. You will need to use a little tool to opend up a gap. Use a small screwdriver or the tine of a fork to get the gap to open up just a little then force the stick in there. It should be a nice tight fit and should stand upright nicely.

This is what it should look like.

Now we are going to make the hinge for the catapult. Stick a layer of tape right down on your table (sticky side down). Yup, stick it right to the table like shown at left. Then stick three more layers of tape right on top of it. You end up with a piece of tape that is four layers thick. Now peel this tape up off the table and ...

and trim it to two inches in length.

Now cut it lengthwise so you end up with two pieces that are two inches long.

Now, using two popsicle sticks as a guide, mark little lines about in the center of the tape pieces. This little area between the two lines is the actual hinge part.

Now tape one of these hinge pieces to your remaining four inch popsicle stick. This is the flat end. The other end of the stick that you can't see in the picture is the rounded end. This is the arm of the catapult.

Put the other piece of tape on the other side of the popsicle stick so it looks likel this.

Now pinch the free ends of the tape together so they stick to each other. And wrap at least three wraps around the stick so it all holds together nice and tight.

You will end up with it looking like this. Make sure the tape is wrapped nice and tight. This is the hinge of your catapult and we will attach it to the base in the next step. Just remember that your little black lines on the tape are a guide to show you where no tape goes. That little free area is needed so the catapult hinges freely.

Okay, let's continue with this tiny catapult project