Materials Required
 Quill tube
 Stand
 Metre scale
Real Lab Procedure
 Arrange the quill tube horizontally on a stand.
 The length of the air column is measured using a metre scale.
 Vertical heights at the two ends of mercury thread from the table are also measured using a metre scale.
 The difference between them gives the vertical height ‘h’ of the mercury thread. Here h=0. So pressure inside the tube is also H, which is the atmospheric pressure.ie; 76 cm of Hg
 The quill tube is then placed in a slanting position with the open end upwards.
 The length of the air column is measured and the vertical height, h of Mercury is noted. Now the pressure inside the tube, P=H + h.
 Quill tube is then placed in different positions, such as: vertical position with open end upwards and with open end downwards, slanting position with open end downwards and measure its corresponding length of the air column l and vertical height h.
 Now P×l is calculated in each case.
Simulator Procedure – (As performed through the Online labs)
 Use the ‘Mercury column length (cm)’ slider to change the length of the mercury column.
 Use the ‘Air column length (cm)’ slider to change the length of the air column.
 The atmospheric pressure (H) is already shown in the window.
 We can change the position of the quill tube by dragging it in different directions.
 Click on the ‘Show Scale’ button to see the 50 cm scale for taking measurements.
 We can click the arrows on the scale to rotate the scale. Also, click and drag the scale to move it to different positions.
 Now, take the readings and calculations are done as per the observation column.
 Click on the ‘Reset’ button to redo the experiment.
Observations
Sl No. 
Position of the tube 
Height of Hg thread from table to 
Vertical height, h = h_{2 } h_{1} (cm) 
Pressure, P = Hh (cm)

Length of air column, l (cm) 
P×l (cm^{2}) 
Lower end, h_{1 }(cm) 
Upper end, h_{2} (cm) 
1 
Vertical (open end up) 






2 
Slanting (open end up) 






3 
Horizontal 






4 
Slanting (open end down) 






5 
Vertical (open end down) 






Calculations
 Calculate P × l in each case.
 Plot a graph between Pressure and reciprocal of length, taking pressure (P) along X axis and reciprocal length (1/l) along Y axis.
Result
From the tabular column, it is found that; P × l is a constant.
The graph between reciprocal of length and pressure is a straight line, which shows that pressure of the given mass of gas is inversely proportional to length of air column.
It indicates the inverse proportionality of pressure and volume of a given mass of gas, hence verifies Boyle’s law.