Children are hard wired to do science. T-Rex (5) and Pony Artist (4) demonstrated this the other day at breakfast. I do not know who started it, but they took turns spinning this spoon.
They discovered that the spoon spins best when just one point touches the table.
They tried placing the spoon with both ends touching the table. It did not spin well, and tended to flip over.
It was a perfect experiment with just one variable: which way the spoon was facing. I pointed out to them what they had done, but they were more excited about the spinning spoon itself.