It’s been a long, strange journey investigating the behavior of syringes and air particles. Along the way, we’ve noticed a series of increasingly powerful patterns. First, we noticed that a closed syringe system would always return to its initial total volume when at rest. So the single syringe always returns to a volume of 20 mL and the two syringes always return to a combined volume of 24 mL. Use your mouse to drag the plungers up and down to see.
Second, we noticed that a closed syringe system would always return to the standard air particle density when at rest. So the plungers of both of the closed syringe systems below always move so that each syringe ends up with about one dot per milliliter (our standard air particle density). Use your mouse to drag the plungers up and down to see.
Finally, we noticed that a closed syringe system (or closed bubble system, for that matter) would always adjust to the air particle density surrounding it. There is nothing special about the standard air particle density except that it happens to be the air particle density all around us (i.e., standard atmospheric pressure).
“If the air particle density surrounding the closed syringe decreases or increases, the plunger in the syringe will move up or down, respectively, to keep the air particle density in the syringe the same as the air particle density surrounding the syringe.”
Change the air particle density surrounding the closed syringe below to see.
So, we have identified a number of significant patterns related to the behavior of syringes and air particles that allow us to make predictions in a wide variety of scenarios. But the one thing we haven’t talked about is “why.” Why do these patterns exist? Why do the syringes or the air particles inside them want to have the same air particle density inside as outside? That is what we will be figuring out next.