Boyle's Law

Question 1

What does pumping a car wheel achieve?

Answer 1

This doesn’t significantly increase volume, but pressure rises until the tyres are taut enough to support car weight.

Question 2

What did Boyle investigate in 1660?

Answer 2

‘The spring of the air,’ - how hard air pushes back when compressed.

Question 3

What experiment did he do?

Answer 3

He investigated pressure-volume relationship for a gas. Increasing air pressure in the reservoir containing oil would force it into the calibrated tube, while decreasing pressure would allow it out. A bourdon gauge measurers pressure, while valve can change pressure.

Question 4

What needs to be constant?

Answer 4

Temperature of the room.
Pressure in the calibrated tube and in the reservoir.
Let oil settle

Question 5

What did Boyle find?

Answer 5

For a given mass of gas at constant temperature, volume is inversely proportional to temperature. A V-P graph shows a steep negative gradient curve which eventually becomes horizontal. A V-1/P graph shows a straight line.

Question 6

What does increasing pressure do?

Answer 6

Reduces volume.

Question 7

What were conclusions?

Answer 7

Provided temperature and amount of gas are constant, pressure is inversely proportional to volume.
pV=K
If volume is constant but amount of gas increases, pressure increases.
Doubling mass is equivalent to halving volume for pressure.
Pressure is proportional to mass/volume, so pressure is proportional to density.