The children were showing interest in aliens, rockets and space. Teacher, James had a water bottle rocket launcher at home, which he brought in. Sadly, this rocket only survived a few launches before the rubber seal broke and could not be replaced.
A week or two later James was reading about an air rocket made from a wine cork and car valve.
“You pump the bottle up until the pressure in the bottle was greater than the friction holding the cork in and in a reverse of a champagne cork the plastic bottle shoots off.”
James then thought about water being in-compressible, so if we fit a hose pipe to the wine cork, the water would flow in and compress the air inside the bottle until the friction failed and launched the bottle.
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