DEGREE OF DIFFICULTY: 1/10
BUILD TIME: 1 Hour
PARTS COST: About $6
· Barrel-shaped plastic container (legs)
· Two 1-cubic-in. wood blocks
· Two 1½-in. cup hooks
· 3-oz. nonlead fishing sinker
· 1-in.-dia. key ring
· No. 64 rubber band
· Drill with 1/8-in. bit
HOW IT WORKS
Rolling the jug transfers energy from the container to the suspended sinker, causing it to swing like a pendulum. When the jug stops, the sinker keeps oscillating, and the return stroke rolls the jug back to the rollee—that's you!
HOOK, HOLE, AND SINKER
1. Drill centered holes in the lid and the bottom of the container and partway into both wood blocks.
2. Feed a hook through the inside of the lid and screw it into one block; repeat on the bottom. Both hooks should face the inside of the jug.
3. Thread the sinker on the key ring; tie the rubber band to the key ring.
4. Loop the rubber band onto the hooks and screw on the lid.
5. Roll the jug on the floor. When it stops, marvel at what happens next..