Water Rocket with easy launching pad (simple!)

Step 2 Fins!

Cut out a section of your plastic (using utility knife) and draw your desired fin shape in the piece of plastic. Cut this fin out, and use it to trace two more fins. When done tracing, cut out remaining two fins. Next, fold the edges of the fins over about 1/2cm where they will be in contact with the rocket. This provides a bigger surface area when glueing the fins. Discard the remaining plastic.

Use the images below for help: