Why is fire hot?

I didn't ask this question, it was my cousin in kindergarten. In order to solve the problem of nong in words that he could understand, I racked my brains to make up a statement.

"Don't you see that the air around the fire is hot? This means that the fire can make things around it hot, and when it gets hot to a certain extent, this 'heat' becomes 'hot'. If you don't believe me, you can boil a pot of cold water and put your hands in it. You will see that the fire makes the water 'hot' and finally 'hot'。。。。。。 ”

This wordplay-like solution is certainly not the answer. It would be cumbersome to really explain the problem. This problem can be viewed from two perspectives: materialism and idealism.

Since we are staunch adherents of Marxism, I will explain how we view this issue from a materialist point of view.

How did the fire come about?

It is a natural phenomenon produced by combustion. It is the effect of bond breaking and releasing energy. Heat, or energy, has the effect of transferring, and there is always a tendency from high to low. After the heat in the surrounding air increases, the person transmits the nerve center through the nerves in the skin, and then transmits the signal to the brain to "burn". So the fire is hot.

ps: The bear child is really hopeless

ps2: As a pure-blooded engineering major, I am hopeless if I specialize in physics and chemistry

PS3: I still have to advertise the Q group. Q group: 67259100