My translation homework

James Watt and the Kettle

A Scottish boy was sitting in his grandma's kitchen. Staring at the lurid fire inside the fireplace, he was silently thinking what make things happen. Indeed, he was always wondering why things are happening the way they are.

"Gramma, what makes fire burning?", he asked in a while.
This was not the first time that his gramma was daunted by his question. Therefore she simply continued her preparation for the supper and did not pay any attention to his question.

In an old-fashion kettle hung over a stove, water was boiling, and steam like light cloud was puffed out from the mouth of the kettle. A minute later, the lid of the kettle started to move, rattling. Next, hot steam sprayed out suddenly. However, the boy was looking carefully at what was below the lid but saw nothing.
"Gramma, what's inside the kettle?", he asked.
"Water, kid, nothing else."
"But I know there is something else. It's inside the kettle and pushes the lid up, making the lid rattleing."
Starting to laugh, gramma said: "Ah, that's steam. Did you see the steam that puffs from the mouth of the kettle, cracking beneath the lid?"
"But you just said there is nothing else but water in the kettle. What on earth does the the steam beneathe the lid come from?"
"Oh, honey, it's from the hot water. Hot water makes steam." Gramma started to confuse herself.
The boy picked up the lid, took an careful look inside the kettle to only see the water bubbling but nothign else. The steam can only be seen when it's away from the kettle.
"So strange!" he said, "The steam must be very powerful to be able to lift a lid of this weight. Gramma, how much water did you add to the kettle?"
"About a quart, Jimmy."
"Oh, if the steam generated by this tiny water is so powerful, then the steam generated by a lot of water will be much powerful? Why not let steam lift things much heavier than this? Why not let steam spin wheels?"
Gramma did not answer. She thought Jimmy's questions were different and useless. She kept doing her own works silently while Jimmy was sitting there motionless, studying the kettle.