EXPERIMENT: Combine the simulation titled Ideal Gas Law from Exploration of Physical Science with the actual experiment described below to discover the relationship of P vs V at constant T.
P V = n R T => P V = Constant => P = Constant/V => P = Constant V-1
1) Plot P vs V, do a power fit and display equation on the graph. You should find that P is inversely proportional to V.
2) Find the % difference between the theoretical exponent of V (which is 1) with your experimental.
3) Also from your table of data find the average P x V and its mean deviation (like in the first experiment error)
Note on procedure: Start from 7 cm and increase the volume up to 12 cm in increments of 0.5 cm so that the pressure within the cylindrical piston is smaller than the atmospheric. This is a better procedure safety-wise. Then go down to only 4 cm. For procedure details see Excel file Boyle's Law.
Note on reading the manometer:
Patm = 1 x 105 Pascals => Patm = 105 N/m2 => Patm = 105 N/104cm2 => Patm = 10 N/cm2
Therefore when the valve is open to the atmospheric pressure the numbers 1, 2, 3 and 4 on the manometer are really the numbers 10N/cm2 20N/cm2 30 N/cm2 and 40 N/cm2 respectively. So for example the line on the manometer clockwise of 1 is really 11N/cm2. Also since it is visible where the manometer indicator is, (i.e., between the 11 and 12 N/cm2) then the pressure values can be guessed and reported to accuracy up to the 1/10 of N/cm2. For example 11.7 N/cm2
Note on actual equation:
P V = Constant => P h A = Constant => P h = Constant/A => P h = Const.
Where h = the height of air in the piston and A = cross sectional area of piston.