TED-ED: How heavy is air? - Dan Quinn

The video explains that air behaves like a fluid, with waves and eddies, and is not just empty space. It highlights the density of air molecules compared to interstellar space and how this density creates air pressure. Our bodies balance this pressure, allowing us to survive. Differences in air pressure cause wind and weather changes. Breathing involves manipulating air pressure, and the number of air molecules around us is vast, comparable to the number of grains of sand or stars.

What is a key reason we don't usually notice air around us?

• Air molecules are too small to see.

• Air is considered empty space.

• Air is less dense than water.

• Air is completely still.

Why aren't we crushed by the weight of air in a gym?

• The gym is specially designed to hold air.

• Air pressure inside us balances the external pressure.

• Air only presses on the floor and walls.

• Air is weightless.

What happens when air pressure is not uniform?

• Air becomes heavier.

• Air flows from lower to higher pressure.

• Air flows from higher to lower pressure.

• Air stops moving.

How do we breathe according to the video?

• By equalizing pressure inside and outside the body.

• By holding our breath.

• By lowering the pressure in our lungs.

• By increasing the pressure in our lungs.

What comparison is made to illustrate the number of air molecules around us?

• The number of stars in the universe.

• The number of grains of sand on a beach.

• The number of atoms in a cubic centimeter of space.

• The number of insects on Earth.