Finding odds & ends in Papa's (Grandpa is are retired mechanical engineer) garage we actually only paid $1 for a bag of rubber-bands of different sizes and widths. With 4 sets of hands adjusting and tinkering we entered Kids Invent's 1st Tinker Challenge.
UPDATE: We won first place with our farthest launch of 16'4". Yay! Please check out our rubber-band ping-pong dixie-cup catapult/sling-shot video too.
you need to make the stick longer so the ball wont shoot strait up like that
13jwalters 2 months ago