Son asked : Why is there rain?

One morning, while we were having breakfast, my elder son, +Duy Khoi Pham(PDK) , suddenly asked.

PDK: Daddy, why is there rain?

Fortunately, I had a hot cup of coffee right in front of me. There was some visible smoke coming out of the cup. Seizing the moment, I replied with a question.

Me(PDD): Do you see the smoke coming up from my cup. 

PDK: Yes! 

PDD: That smoke is water when it gets hot. The smoke goes up high into the sky and forms cloud. Do you understand?

PDK nodded.

PDD: So the water now stays in the cloud. When the cloud has too much water, it can't hold anymore and it starts raining.

PDK's eyesight was at the far horizon when our exchange ended. And I was happy surviving an intellectual test from a toddler.