What you Need:
Large shell, cleaned
Plastic bag or old table cloth
What to Do:
1. Cut a triangle from the plastic material with two long sides and a short side so that it looks like a sail. Along the long side the mast will go, make several small openings large enough for the twig to fit in.
2. Thread the twig through the holes.
3. Place a small ball of modeling clay onto the shell hull (the part of the boat people sit in) then stick the twig into the clay. Your boat won't float if you use too much clay so only use as much as needed to keep the twig standing.
4. Sail the your boat in the sink or a small backyard pool.