2.1 Pressure Changes GCSE Physics

BY AYAAN JOHN

What is Pressure?

Pressure is a force applied on a surface, per unit area.

Pressure causes molecules to become tightly packed.

Boyls Law For any given mass of gas , at constant temperature the pressure times the volume is constant.

Therefore take p as pressure and v as volume.

pV= Constant, it can also be

p1 V1= p2 V2. As long as they are both constant and the same.

Temperature and Molecules

It is essential to keep the temperature constant. Otherwise if it is not than it will not follow Boyls law of constant temperature. When you put more pressure on something the molecules start to move faster causing the temperature to rise.

You also have to keep in mind that gas has many free particles and you cannot let it expand.

The higher you go the higher the pressure will be, this is because the volume decreases as we go up, and gravity is a force pushing us down on earth. So we can see how the pressure changes as we go up

Charles’ Law

For any given mass, at constant pressure the volume is directly proportional to the temperature.

Which means if the temperature increases the volume will also increase

Measurements

Pressure is measured in :

PSI (pound per square inch): It’s the unit of measurement where one pound of force is applied to one square inch of the area. This unit is used in the United States.

BAR: One BAR is equal to the atmospheric pressure on earth, at sea level.

PA (Pascal): This unit of measurement for one newton of pressure per square meter.

Examples.

Hot air Balloons.

Dented T.T ball: If you put it in hot water the pressure inside the ball will increase due to the particles becoming hot and moving faster.

Coke can: If you do not keep it in a cold place like it says on the bottle the Carbon Dioxide will expand, and as per the law the volume is constant so the can will burst.

Bibliography http://www.learnthermo.com/T1-tutorial/ch01/lesson-E/pg03.php

http://www.eo.ucar.edu/basics/wx_2_d.html

http://www.grc.nasa.gov/WWW/k-12/airplane/glussac.html

http://ap-physics.david-s.org/pressure/

http://www.askturck.com/docs/TURCK-Types-of-Pressure-White-Paper.pdf

http://2012books.lardbucket.org/books/principles-of-general-chemistry-v1.0/s22-chemical-thermodynamics.html

https://prezi.com/myiigflss0gg/charless-law/

http://www.blimpinfo.com/uncategorized/11-die-in-nz-balloon-crash/

http://howto.wired.com/wiki/Fix_a_Dented_Beer_Pong_Ball

http://www.one-school.net/Malaysia/UniversityandCollege/SPM/revisioncard/physics/forceandpressure/images/atmosphericpressure_clip_image0011.gif

http://www.npl.co.uk/upload/img_400/Altitude_vs_Pressure.gif

http://askthephysicist.com/images/BrittanicaPressure.gif