Why is cold air denser than warm air?

Answer 1

For the same mass of air, the warm air has expanded and has a bigger volume. The molecular theory explains it by the fact that the air molecules have acquired extra kinetic energy from the heat energy of the warmth. So the warmer air molecules are moving faster and occupying a larger space (volume).
Since density is mass per unit volume it is logical that the same mass divided by an increased volume means a lower density.
So cold air is denser than warm air or warm air is less dense than cold air.

Answer 2

This is true to a point. At 32 degrees Fahrenheit air molecules crystallize and the performance quality of the intake air starts to diminish. The exact temperature for peak performance is still very argumentative. Warm air allows for better air/fuel atomization and burns more efficient, but you were discussing performance. Hope this helps. Christopher

Answer 3

Because heat energy gained by warm air molecules weakens the bonds between them. Therefore, the bond length will be reduced and the molecule will be farther apart from each other.

Answer 4

When air is warm its molecules become more agitated and move farther apart. Cold air molecules are less energetic and remain closer together.

Answer 5

Ok, think of it this way. Suppose you have a cube of nitrogen atoms, it doesn't matter the size. These atoms vibrate bumping into each other and the more they vibrate, the more space they take up. The warmer it gets they more they vibrate taking up more space leaving less room for atoms that can fit into the cube. Less atom means less density and because there is less matter it weighs less.

Answer 6

every gas follows a gas law pV=mRT

density is m/V. so, clearly density and temperature are inversely proportional. So, if temperature increases, density will decrease, given pressure is a constant