This 16 foot long earthworm/bicycle was raced in the Davis Deadly Derby VI with Team Worm Bin (Me, Clara, Jenny, Bobby, and Rezz). We got third place out of 10 teams! It's support frame is 3 inch PVC pipe, the skin is from burlap sacks, and stuffing is straw. It weighs about 35 lbs, cost about $40 to build (not including bike), and was 6 hours in the making. Clara and Jenny had dung beetle costumes and compost bins (cardboard) were zip tied on some bikes.
Step 1: Plan the dimensions
I had a 14 foot length of PVC pipe that someone drove a truck over, so I got it free. 14 feet long was the basis for the dimensions. How wide should a 14 foot earthworm be? I sketched a worm on a piece of paper and decided a one foot diameter worm would look right. Don't plan too much though. Just start building!!!
Image from Ms Peck's 2nd grade class