Question

Which of the following explains convection of air in the atmosphere (the answers to this questions explans why L's mean cold and H's mean warm on the weather news)?A. Hot air rises, forcing cold air down while low pressure results from falling cold air and high pressures from rising hot air.B. Hot air falls, forcing cold air up while low pressure results from falling hot air and high pressure from rising cold air.C. Hot air rises, forcing cold air down while high pressure results from falling cold air and low pressure results from rising hot air.D. Hot air falls, forcing cold air up while high pressure results from falling hot air and low pressue from rising cold air.

Answer 1

Molecules are heated and move faster when the air is hot, so they are moving away from each other, creating more space between them. This makes the density of the air be lower than the density of cold air. As hot air is less dense, it will "float" and rise, forcing cold air down. Therefore, B and D are incorrect.

When air rises, you have less molecules close to the surface so the pressure that the air puts on the surface is lower, but when dense cold air comes down the pressure will rise again.

Therefore, the correct answer is C. Hot air rises, forcing cold air down while high pressure results from falling cold air and low pressure results from rising hot air.