Syringes work by utilizing atmospheric pressure and are related to atmospheric pressure.
The syringe consists of a barrel with a small hole in the front and a matching piston mandrel, which is used to inject small amounts of liquid or its into areas that are inaccessible by other means or to draw it out of those areas; the liquid or gas is drawn in through the small hole in the front of the barrel when the mandrel is pulled out, and squeezed out when the mandrel is pushed in.
When the piston is slowly pulled up, the pressure at the front end of the piston is less than the atmospheric pressure, while the pressure at the surface of the liquid is equal to the atmospheric pressure, and the liquid is pressed into the syringe by the atmosphere under the effect of pressure difference.
Extended information:
I. Causes of air pressure
From the molecular theory of motion, it is known that the pressure of a gas is generated by a large number of molecules frequently colliding with the walls of the container. A single molecule on the container wall of the collision time is very short, the role is discontinuous, but a large number of molecules frequently collide with the wall, the wall force is continuous, uniform, this pressure and the ratio of the area of the wall is the size of the pressure.
Two, the use of syringes
Syringes can also be used for medical equipment, containers, such as some chromatography in the scientific instruments injected through the rubber diaphragm. Injecting gas into a blood vessel will result in an air embolism. Air is removed from the syringe to avoid embolization by inverting the syringe, tapping it gently, and squeezing out a little liquid before injecting into the bloodstream.
In settings where precision is the primary concern rather than germs, such as in quantitative chemical analysis, glass syringes are still used because of their small margin of error and smooth pushrod movement.
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