An air conditioning unit positioned near the ceiling of a room is switched on to cool the room. A sealed rubber balloon inflated with air is lying on the floor.
When the air conditioning is first switched on, the temperature of the air immediately above the floor decreases more quickly than the temperature of the air in the rest of the room. Explain why this happens.
As the room cools, the temperature of the air inside the balloon decreases, causing the balloon to contract and the volume occupied by the air to decrease. State what happens to the motion of the air particles inside the balloon as the temperature decreases.
As the balloon contracts and the volume of the air inside decreases, the pressure of the air remains constant. Explain, in terms of the particles of air, how the pressure of the air remains constant.
321 exam-style questions on CIE IGCSE Physics 2.1 Kinetic particle model of matter, covering 2.1.1 States of matter and changes of state, 2.1.2a Particle structure and motion in solids, liquids and gases, 2.1.2b Gas pressure and particle collisions, 2.1.2c Brownian motion, 2.1.3a The absolute scale of temperature, and 2.1.3b Pressure, volume and temperature of a gas. Each one has a worked solution and a mark scheme showing where the marks go.