Evan Murphy

– N5 Physics Assignment

Boyle’s Law

Aim

To investigate if the pressure of a gas which has a constant

mass varies when the volume is changed.

Underlying Physics

The particles in different gases have a lot of free space to

move around in which means they tend to collide with each other and bounce off

of the container walls. Collisions are likely to occur more often when the

volume is decreased. The particles will have more energy if the temperature is

increased which means that there will be more collisions per second which will

mean that particles will collide with a much larger force. Pressure is the

force per the unit of area and can be determined by the equation:

P= Pressure in (Pa)

F= Force in (N)

A= Area in (m2 )

The Kelvin scale can change 0 Celsius into -273o K. To

convert Celsius to Kelvin you simply just do the calculation of (degrees Celsius)

– 273, this will give you your answer in Kelvin. This lets us know the volume of

a selected gas as you can work backwards for example if you know the gas is 243o

K you will know the temperature is 30o C.

Method

The air was trapped in a cylindrical container with oil. The

container was connected to a pressure gauge and a pump. The pressure gauge was

there to measure the pressure and the pump decreased the amount of air which

was in the cylindrical container.

The following values are the results of the experiment

pressure against 1/Volume:

Air Volume

(cm3)

1/Volume(cm-3

)

Pressure 1

(kPa)

Pressure2(kPa)

Pressure3 (kPa)

Average

Pressure(kPa)

10

0.1

256

253

259

256

15

0.07

180

180

180

180

20

0.05

148

130

130

136

25

0.04

109

100

90

100

30

0.03

100

83

77

80

With the results above we plotted a graph with a line of best

fit.

Analysis

The second source I have compares with my own graph as they

are both a straight line which goes through the origin. This shows that if

volume increases, pressure decreases. See

next page for second source.

Conclusion

The aim of the experiment I did was to investigate if the

pressure of a gas which has a constant mass varies when the volume is changed.

The experiment results show that there is definitely some relationship between

the change in pressure and volume.

Evaluation

To make my experiment more accurate I did the experiment

three times and with these results I calculated the average. Having three sets

of results meant that there was more of a chance for an accurate experiment due

to having more values to work with.