Let’s talk about something suggested by a Clear Science reader: What is Pascal’s Emptiness in Emptiness experiment? It was an experiment done in the 17th century by Blaise Pascal, who made many contributions to science. First let’s talk about Pascal and what those contributions are.
The SI unit of pressure is the pascal (Pa), taken from his name. Standard atmospheric pressure is 101,300 pascals, or 101.3 kPa. Atmospheric pressure is caused by the weight of air above you, pushing down. If all the air went away, the pressure would feel like you were in outer space, because nothing would push down on you.
(BS alert: It’s not actually “down.” More properly it’s “normal” to any surface. But if you don’t know what normal means, down is an all right way to think of it.)
If you watch the weather report, you’ll notice that the atmospheric pressure changes day to day. This is because the air is constantly in motion, and sometimes there is less on top of you than usual. (And sometimes more.)
