A Scottish little boy was sitting in his grandma's kitchen. Looking at the reddish fire in the large fireplace, he was thinking about the reason why it happend. Actually, he had always been confused, and had always been curious about what happened.
"Grandma, what makes it on fire?" in a little while he asked .
It was not the first time that his grandma was stumped by him, so she kept cooking her dinner, ignored his question.
In the old fasioned pot hanged on the fireplace, water started boiling with mist-like vapor coming out of the spout. After a while, the lid started being lifted, with giggling noise.
The vapor was suddenly spouting out, and the boy peeped under the lid, but saw nothing.
"Grandma, what is inside the pot?" he asked.
"Water, boy, nothing else."
"But I know there is something else since the lid was lifted and produced giggling noise."
Grandma started laughing, said, "Oh, that is vapor. You may see vapor coming out from spout, and also bubbling under the lid."
" But you just said that there is nothing else except water in the pot. Then where is the vapor coming from?"
"Oh, my dear, it comes from the hot water. The hot water produces vapor."Gradma started feeling that she was unable to explain it clearly.
The boy lifted the lid, peeped into the pot again, only saw the water in the pot bubbling, nothing else was found. Vapor was only visible after it left the pot.
"How strange it is!" he said. "To lift such a heavy iron lid, the power of vapor must be big. Grandma, how much water was in the pot?"
"About one quant, Jemmy."
"Oh, if the power produced by such little water is so big, then the power produced by large amount of water would be much bigger! Why would not we make vapor lift things heavier than this? Why would not we make vapor turn a wheel?"
Grandma did not answer. She thought, Jemmy's questions were useless, but hard to answer. She kept doing her things, while Jemmy sat still at the original place and thought about the pot.
