Chemistry · Lesson Worlds
Diffusion: interactive science lab
Warm the rooms or open the door and prove that mixing is particles wandering, not a pump.
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What will you learn?
Particles wander from crowded to empty. Heat makes the wander faster. A closed door stops it. No one has to stir.
How does the lab work?
Observe the simulation, make a prediction, change a variable, run the experiment, and explain the result. Finish with a challenge that tests your understanding.
You can change: Temperature, Opening. Compare what happens and connect the result to the scientific explanation.
Try a comparison in Diffusion
Start with the lab’s initial settings. Choose one control below, predict the result, and change that control while keeping the others fixed. Record the setting and what you observe before making a second change.
- Temperature: the lab starts at 20 °C; its available range is 5–80 °C.
- Opening: the lab starts at 1; its available range is 0.12–1.
For a named starting condition, try Cold, Room, Hot, Almost shut. A preset can change several settings: check the controls before treating two presets as a one-variable comparison.
Questions to discuss during the activity
- Watch what happens. Nothing pumps it. The particles just keep moving. Watch dye wander into the empty room.
- Name the cause. Each particle steps at random. From the crowded side, more steps go out than come back, so the color spreads. Heat makes bigger, faster steps. A nearly shut door lets few across. Crowded places leak into empty ones.
- Change something. Warm the rooms and the mix should finish sooner. Change temperature, then open.
- Guess before you run. If we warm the rooms to 60 °C, the dye will… Guess what will happen, then run to check.
After your comparison, explain how the observations connect to this idea: Particles wander from crowded to empty. Heat makes the wander faster. A closed door stops it. No one has to stir. Name one condition you held fixed and one feature of the real world this model simplifies. A completed run is a starting point for discussion, rather than proof of mastery.
Who is it for?
Curious learners exploring chemistry. A parent or teacher can help younger learners read the instructions and discuss the results. Choose by topic and prior knowledge rather than a fixed grade level.
Is this lab free?
Yes. This interactive lab is free without signing in or a paid membership.
No app download is needed; interactive play requires JavaScript and a modern browser.
Use this activity with a learner
Families and educators · choose by prior knowledge
Learning goal: Particles wander from crowded to empty. Heat makes the wander faster. A closed door stops it. No one has to stir.
Before you begin: Read the controls for Temperature, Opening. Make one prediction before changing a setting.
Check understanding: Ask for one observation, the evidence that supports it, and a question to investigate next.
A simulation simplifies the real world. Explain which conditions stayed fixed; a successful run alone does not demonstrate mastery.
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