Problem: - Above the oven is a tank of water that is sealed - The tank of water begins to boil above the oven - A the water boils steam is created - The steam is denser than air so it needs a place to go - The steam is forced out of the tank and into a piston - The piston moves up - The valve of the piston closes - The valve on the next piston opens - The steam fills the next piston, driving it up, and the other one down - What might be the first step of the process?

A: A fuel is heated in an oven

Problem: - The heated water evaporates - The salt is left behind - The evaporated water condenses on a cold surface - The evaporated water is collected - The process is repeated - More salt is removed from the water. What might be the first step of the process?

A: Water is heated

Problem: - The rocky area has a higher elevation than the surrounding areas - Water from precipitation falls in the area - The water forms a stream - The stream flows towards lower elevation - The stream becomes a river - The river continues to flow along the same path for a long time - The river erodes the rocky area that it touches - The eroded area cuts deeply into the rock. What might be the first step of the process?

A: A large rocky area is formed

Problem: - The radiation is aborbed by the Earth - Some of the radiation goes back into space - Some is trapped by the atmosphere - If too much heat is trapped - Global warming occurs. What might be the first step of the process?

A:
The sun gives off radiation