Practice Model of Water - 3.3.3 Increasing the Pressure of a Gas (Physics Only) HT only (GCSE Physics AQA)

Increasing the Pressure of a Gas (Physics Only) HT only

Work

• Work is the transfer of energy. Work done is simply another way of saying that energy is transferred. The energy is usually transferred by a force. You may wish to re-cap our previous work in 4.1 Energy.
• Doing work will increase internal energy. By doing work on a gas (for example increasing its pressure), we can increase the internal energy of the gas. Previously, we discussed that the internal energy is the combination of kinetic energy and potential energy of the particles.
• Internal energy affects temperature. As the internal energy of the particles increases, the temperature of the gas also increases. The kinetic energy has been increased and therefore the gas becomes warmer.

Example: A Bicycle Pump

Question: Yasmin is using a bike pump. As she is inflating her bike tyre, she feels the pump handle getting warmer. Why is this happening?

More particles are being forced into the tyre. As Yasmin is pumping up the bike tyre, she is making more air particles move into the tyre. She is doing work against a force for this to happen.

Kinetic energy of the particles increases. By doing work, Yasmin is transferring energy to the particles inside the tyre. This energy is converted into kinetic energy.
Increased KE leads to increased temperature. The increase in kinetic energy will result in the temperature of the tyre increasing.

Tyre is connected to the pump. The tyre is connected to the bike pump, therefore as the tyre gets warmer, Yasmin will feel the bike pump also getting warmer.