Two connected syringes filled with water: What happens when the plunger is moved outwards?

Suppose we have two syringes -- both in the halfway position -- filled with water and connected by a tube (there is no air in the system, only water).

If we push one of the syringe plungers in, then the other syringe's plunger will move outward. I'm content with this

What happens if I pull out one of the syringe plungers though? Would the other plunger move in?

• If the extra volume I have introduced was filled with air, then I think maybe nothing would happen, since the air would maybe keep the pressure the same?
• But since there is no air in the system, I think this would introduce a vacuum, at which point I don't know what happens. One thought is that pressure in the syringe whose plunger I pulled out would have to decrease (since the volume has increased), but I don't know whether this would move in the other plunger.

So to state the question once more: Suppose two plungers are connected as described in the first paragraph. If we pull one of the plungers out, what happens to the plunger of the other syringe, and why does this happen? (i.e. if a force is being exerted what is causing this force?

• Sounds like you are assuming that the tube that connects them will not collapse. I probably can find samples of flexible tubing in the shop at work that will not collapse before the plunger of the second syringe moves, and I probably can find other samples that will collapse. Commented May 29, 2020 at 19:40
• @SolomonSlow Yes, I was implicitly assuming that Commented May 29, 2020 at 19:52