Mandela's Blog

Pressure
is the force divided by the area on which it is exerted.
Pressure at sea surface give 101300 Pa or 760 mmHg or 1atm.
Higher a place from sea surface, smaller its atmospheric pressure then at sea surface.

Manometer

Measuring device of air pressure called Manometer



Pressure of Gas Law
There are three law about air pressure :

• Boyle’s Law

• Charles’ Law

• Combined Law

Boyle’s Law
Boyle’s law states that for a fixed sample of gas at constant temperature, the volume of the gas varies inversely with the pressure.
PV=constant, or P1V1 = P2V2
If you make the volume bigger, so the pressure bigger if the temperature is constant.



Charles’ Law
At constant pressure, the volume of a given mass of an ideal gas increases or decreases by the same factor as its temperature increases or decreases.
V1/T1= V2/T2



Combined Law
Based on the Boyle’s and Charles’ Law, so


When,
P is the pressure.
V is the volume.
T is the temperature

Application Drinking Straw

When someone drink from drinking straw,
he/she make the straw pressure lower than
air pressure and make water pushed into the straw

Label: Pressure