Skip to content

Search the chemistry universe

Elements, molecules, concepts, simulations, experiments and pages.

Enter a formula, name or conceptFull search

Gas law lab

Move one thing, hold two still, and watch the fourth answer.

SchoolLive

Scientific learning path

  1. 01UnderstandLive
  2. 02ExploreLive
  3. 03ExperimentLive
  4. 04ObserveLive
  5. 05ExplainLive
  6. 06ApplyLive
  7. 07TestBuilding
Explanation mode

The particle count is illustrative, not the number of molecules — a mole is far too many to draw. Their speed tracks the temperature.

Law
Held still: Temperature, AmountThe gas answers with: Pressure

Description of this simulation

Boyle's law: At a fixed temperature and amount, pressure is inversely proportional to volume. The gas is at 100 kilopascals, 22.71 litres, 1 mole and 273.2 kelvin, which is 0 degrees Celsius. Moving the volume changes the pressure; the other two are held still.

PV = nRT

At a fixed temperature and amount, pressure is inversely proportional to volume.

The gas right now

Pressure
100 kPa
Volume
22.7 L
Amount· Held still
1 mol
Temperature· Held still
273.2 K
In Celsius
0 °C

Temperature here is absolute, in kelvin. Halving a Celsius reading does not halve the volume: 100 °C to 50 °C is 373 K to 323 K, a fall of thirteen per cent, not fifty.

The relationship

Volume (L)Pressure (kPa)

Every point on this curve is the same calculation as the reading above it.

What "ideal" leaves out

An ideal gas has particles of no size that do not attract each other. Real gases follow this closely at everyday pressures and drift from it when cold or squeezed hard — which is exactly when they condense, something an ideal gas can never do.

What this model shows — and what it simplifies

Educational Model

Every reading comes from PV = nRT solved for the unknown, never from a proportion written to look like the law.

Where do we see this in real life?

A bicycle pump warms as you compress the air, an aerosol can warns against heating, and a bag of crisps swells on a mountain pass. All three are this one equation.