Hands On Physics

The Great Bungee Jump
Core Project
Step 1: Building the Tower

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Overview. This page details one way to make a scale model of a bungee jump. It consists of a tower made of plastic pipe.

The tower is made of plastic (PCV) plumbing pipe and connecting fittings. The plastic pipe is easy to cut with a hack saw and can be assembled with slip-on fittings and locked in place with small screws. See tools and materials for a complete list of the parts required.

1. Cut the PVC, if necessary. Start by cutting the pipe to the lengths required.

2. Assemble the base. The support for the long vertical pipe is a tee fitting attached to two angled pipes. Fit these together as shown in the photo below. .

Attach two short pipe segments to the tee. Attach a 45° elbow to these. Attach a 30 cm length of tubing to each elbow. Slip the 2.5 m vertical support into the upright part of the tee.

3. Mark the joints. Stand the tower in the tee of the base, and with the help of your partners, square up the tower and arrange fittings in the base so that the base is firmly on the floor. You may want to hold the tower against a wall to make sure it is vertical. When you are satisfied with the position of the tower and fittings mark the pipe and fittings so that you line them up again later.

4. Make the base rigid. This tower is big and awkward to store, so you want to be sure it can be dissasembled later. You can hold most of the joints together with tape, but four of the joints need to be rigid or they will twist and the tower will fall or lean. Figure out which joints need to be rigid. To make these joints rigid, you have two options:

• Screw the joints together so they can be unscrewed later. This takes some patience, but leaves you with a base you can dissasemble. Drill one hole through each fitting into the end of each pipe so that you can lock the pipe and fitting together with a screw. Be careful to make sure that the fittings and pipes are aligned using your marks before you drill the holes.
• Glue the joints. This requires using the special PVC pipe glue sold in hardware stores. If you use this, be careful to follow the manufacturer's directions; the glue is flammable and noxious. Be careful to make sure that the fittings and pipes are aligned using your marks before the glue sets.

5. Add the top. The tower needs a horizontal pipe that can hold the release mechanism so that the weight falls about 20-30 cm away from the vertical pipe. Attach a 90° elbow and a short piece of pipe to the top of the tower.

Congratulations! You now have a tower model you can use for experiments on the Great Bungee Jump! Now you need some electronics for the experiment.