What is convection? (book answer)
The movement of air going from one density to another.
How does a water cycle work?
When water evaporates, it goes to the clouds and then, the water freezes, but the water soon melts. After the water melts, it's turned to rain and falls back to land. And the whole process restarts.
What is density (book answer)
How much in a certain space.
How does water evaporate?
The sun causes the water to evaporate.
If you pumped air in a bottle, the density of air particles in the bottle will be greater than the density outside the bottle.
How is lightning made?
Lightning comes from charges that build up in a storm cloud.
What creates wind? (full answer)
There is warm air on the ground, and then cold air sinks the bottom, pushing the warm air up. Then the cold air moves horizontally, creating wind.