100,000 Pa near sea level and decreases as altitude increases. More simply, it is the force exerted by the weight of the air.
to the air pressure at sea level, they forget that they are being “pushed on” by the air all of the time! Because these air
molecules have a lot of “empty” space between them, they can be compressed in order to fit inside of a smaller volume.
air inside their bodies too. The air inside their bodies balances with the air outside and keeps them from getting squished.
air collide with the walls, they exert a pressure on the container.
If more particles collide in a given amount of time, then more energy is transferred to an object.
the inside and outside air pressure is the same.
is heated, the air particles absorb the heat energy and become more excited. This makes them move faster, which means they
collide with a surface more often, and with greater force. For this reason, hot air exerts greater air pressure per particle
than cold air, so you don't need as many air particles to build to the same pressure level.
equal to the inward pressure of the surrounding air. That way, each portion of the envelope will experience zero net force
and the balloon will not be crushed. A balloon with a very thin outer shell wouldn’t work because it would be crushed by the
atmospheric pressure, with each square meter of its outer envelope experiencing a force of 100,000N. While a thick outer shell
could withstand the pressure, it would be too heavy to float in the air.
balloon with outside air would make its average density too high. A hot air balloon contains fewer particles, has less mass,
and weighs less than it would if it contained cold air.
balloon doesn’t have to be sealed.
and outside of the balloon. It will eventually reach the flight ceiling, or the point at which the air is too thin to lift
it any higher.