Ladder
Kinetic theory — the ladder
2 distinct arguments against one idea, from the one that introduces it to the one that assumes the rest.
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The speeds in a still room
The air in a quiet room is not still. Every molecule in it is moving at hundreds of metres per second, and temperature is a single number summarising an entire distribution.
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Pressure is a rate of arrival, and the gas law falls out of counting
Nothing in a gas is pushing on the walls. Molecules arrive, bounce, and leave, and pressure is the momentum they deliver per second — from which the ideal gas law follows with no thermodynamics in it at all.