Some, think of how much the atmosphere weighs as a whole. At sea level, every square inch has 14.7 pounds pressing down on it, now multiply that by the surface of the Earth. That's a lot of mass, you don't even think about it because your experience with air doesn't show you the mass. Air is really freaking heavy, if it wasn't for air pressing down on you your blood pressure would make you bleed out of your eyes. It's because air is just a medium to transmit energy, air has energy in it, Oxygen in the air is responsible for fire. What is fire? It's just rapidly forming compounds. Free radicals come along and rip molecular bonds apart, energy is consumed, and then the broken molecules bond with other broken molecules and release energy in the form of heat. It's crazy right, breaking bonds absorbs energy, temperature goes down, forming bonds releases energy, temperature goes up. It's just like with people, you break bonds, you get depressed, energy is absorbed, you form bonds, energy is released, you feel good.