[RKDinOKC]

Before the age of the potato gun we made tennis ball cannons by duct taping soup cans together.

We set one straight up and fired it off to see how high the ball would go. When the tennis ball disappeared up into the sky we all ducked under the eaves of the house. After a moment our tennis ball cannon was destroyed by the tennis ball it had just launched. We couldn't believe it came right back down in the same place it was launched.