Gas & States Lab
Gases feel abstract until you can see the molecules. This is a box full of them. Squeeze the volume, turn up the heat, add more gas — and watch the pressure answer back. Then heat a real substance and watch it melt and boil, particle by particle.
One equation ties it all together: PV = nRT
Every "gas law" is this single relationship with two things held still:
- Boyle's Law — hold temperature and amount fixed: squeeze the volume and the pressure rises. Their product P·V stays constant.
- Charles's Law — hold pressure fixed: heat the gas and it expands. V ÷ T stays constant.
- Gay-Lussac's Law — hold volume fixed: heat the gas and the pressure climbs. P ÷ T stays constant.
In the lab, move just one slider and read off the law that names what you did — the graph traces the exact curve PV=nRT predicts.
Why pressure exists at all
Pressure isn't a mysterious force — it's countless molecules drumming on the walls. Pack more of them in (raise the amount), speed them up (raise the temperature), or give them less room (shrink the volume), and the drumming gets harder. That's all pressure is.
Switch to States of Matter and drag the temperature slowly through water's melting point (273 K) and boiling point (373 K). Watch the lattice let go, the liquid pool and flow, and finally the particles fly apart as steam.