Experiment 2: Diffusion Rate Visualisation
This experiment visualises the diffusion rates of different gases, demonstrating how molecular weight affects the speed at which gases spread. You can observe diffusion with and without buoyancy effects:
- Without Buoyancy: Observe pure diffusion based solely on molecular motion.
- With Buoyancy: See how gases with different densities move when buoyancy forces are applied (lighter gases rise, heavier gases sink).
Select different gases and toggle between modes to compare diffusion behaviors.
Diffusion Statistics
Average Diffusion Rate (Gas 1)
Average Diffusion Rate (Gas 2)
Diffusion Rate Ratio
Molecular Weight Ratio
The Science of Gas Diffusion
Diffusion is the movement of particles from an area of high concentration to an area of low concentration. The rate of diffusion is influenced by several factors:
Graham's Law of Diffusion
Graham's Law states that the rate of diffusion of a gas is inversely proportional to the square root of its molecular weight:
Rate ∝ 1/√M
This means lighter gases like hydrogen diffuse faster than heavier gases like carbon dioxide.
Buoyancy Effects
In addition to diffusion, gases in Earth's gravity experience buoyancy forces:
- Gases less dense than air (like hydrogen and helium) tend to rise
- Gases more dense than air (like carbon dioxide) tend to sink
This experiment allows you to observe both pure diffusion (without buoyancy) and the combined effects of diffusion and buoyancy.
Factors Affecting Diffusion Rate
- Molecular Weight: Lighter molecules move faster and diffuse more quickly
- Temperature: Higher temperatures increase molecular motion and diffusion rates
- Pressure: Higher pressures can decrease the mean free path and affect diffusion
- Molecular Size: Smaller molecules generally diffuse faster
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