Q. Why is water converted to steam by the heat of fire?
A. The heat of the fire (entering the water) divides its globules into very minute bubbles, which (being made lighter than air) fly off from the surface in the form of steam.
Q. Why does not wood melt, like metal?
A. Because the heat of the fire decomposes the wood into gas, smoke, and ashes; and the different parts separate from each other.
Q. What is meant by vaporization?
A. The conversion of liquid into vapour; as water is converted into vapour by the heat of the sun.
Q. What are clouds?
A. Moisture evaporated from the earth, and collected in the upper regions of the air.
Q. What is the difference between a fog and a cloud?