Air Pressure: Truth or Lie?

What if I told you air pressure was so great it could crush a can?  Push an egg into a bottle?  Would you laugh at me?  Is it true? Or am I trying to pull your leg?

It's all true!  It's science!  I can explain this completely and truthfully!  So what is going on with air pressure?  

Air pressure is the weight of air pressing down on the Earth.  Do you remember the definition of weight?  

Every object has mass.  No matter where you go in the UNIVERSE, your mass will stay the same.  But, if you go to different planets, or moons, asteroids or comets, gravity pushes down on your mass and you can measure that as WEIGHT.  

Weight depends on the force of gravity pushing down on your mass.  Back to air pressure....

Air molecules will pool in the lowest places, valleys, sea level, Death Valley....this is high pressure.  The pressure is lower the higher you go into the atmosphere.  When you are in a valley or near the ocean your body tissues are compressed together.  If you are in the high mountains your body actually expands, the tissues can actually put pressure on joints and cause pain when hiking at higher altitudes.

So yes, air pressure can crush an aluminum can.  Yes, air pressure can push an egg into a bottle.  

What about weather?  Is it the same for weather?

When the weather is sunny and fine, not a cloud in the sky, air pressure is HIGH.  The cooler, dryer air is sinking to the ground and displacing the warmed air, causing it to rise up.

When the weather is stormy and cold, air pressure is LOW.  The cold air and precipitation that comes with storms, forces the warm air up.  The cooler air is always going to sink because cooler atoms will clump together, become more dense and sink to the lowest spots on Earth. 

This weather map shows you how air flows because of high and low pressure:

The cooler air is sinking and forcing the warmer air to move up.  Because heat transfers from hot to cold...air pressure goes from HIGH to LOW.  This creates spinning swirls of moist air and or dry air.

Winds blow towards a LOW pressure system. As the moist air rises and condenses, this feeds storms and much precipitation is the result.  A HIGH pressure system will replace the air that has risen causing the storm to come to an end and fine weather returns.