The pressure inside a syringe increases primarily by decreasing its volume.
Specifically, according to the reference:
- When the plunger is pushed back in, the volume decreases and the pressure increases. This action reduces the space inside the syringe barrel, forcing the fluid molecules closer together, thus raising the pressure.
Here's a more detailed breakdown:
- Volume Reduction: The act of pushing the plunger reduces the space available for the fluid (liquid or gas) inside the syringe.
- Pressure Increase: As the volume decreases, the molecules of the fluid collide more frequently with each other and the walls of the syringe. This increased collision rate is what we perceive as an increase in pressure.
- Fluid Ejection: Once the internal pressure exceeds the external pressure (e.g., atmospheric pressure), the fluid is forced out of the syringe through the nozzle.
In summary, pressure within the syringe is raised by physically reducing its internal volume using the plunger.
