Air Particles and Syringes Don’t Have Brains
Here is one artist’s depiction of what happens inside a vacuum chamber when the air is sucked out.
Ha. Ha. Seriously. Air particles and syringes don’t have brains. The air particles inside the syringe don’t “want” to be at the same density as the air particles surrounding the syringe. The plunger doesn’t “want” to go back to the volume it started at. Air particles and syringes aren’t little people — they don’t “want” anything. So how and why does the plunger move? What physically causes it to move? Great questions.