* Atoms and molecules have mass: All matter is made up of atoms, and atoms have mass. Molecules, which are groups of atoms bonded together, also have mass.
* Air is a mixture of gases: Air is primarily composed of nitrogen (N2), oxygen (O2), and smaller amounts of other gases like argon, carbon dioxide, and water vapor. These gases are made up of molecules, which have mass.
* Mass is additive: Since the individual molecules in air have mass, the total mass of air is the sum of the masses of all its constituent molecules.
Evidence:
* Weighing air: While air is light, it can be weighed. This is how we know it has mass.
* Air pressure: Air pressure is a result of the weight of air pressing down on a surface. This weight is due to the mass of the air molecules.
* Wind: Wind is the movement of air masses. These masses have inertia, which is a property of mass.
So, the next time you feel the wind on your face, remember that you are feeling the force of air molecules with mass in motion!
