Chemistry · Lesson Worlds
Conservation: interactive science lab
Move mass from start to product and prove that the total does not change.
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What will you learn?
Mass is conserved in a closed reaction. What leaves the start flask shows up as product. The sum stays put.
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: Moved to product. Compare what happens and connect the result to the scientific explanation.
Try a comparison in Conservation
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.
- Moved to product: the lab starts at 3 g; its available range is 0–8 g.
For a named starting condition, try Little, Room, All. 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. 3 + 5 = 8. The total did not blink. Watch 3 g move to product. 5 g stay.
- Name the cause. Lavoisier’s point: in a closed flask the mass at the end matches the mass at the start. Product is the same stuff in a new arrangement. Atoms are rearranged, not deleted.
- Change something. Move more to product and the start flask should shrink by the same amount. Change how much you move, then react.
- Guess before you run. If we move all 8 g to product, the total mass will… Guess what will happen, then run to check.
After your comparison, explain how the observations connect to this idea: Mass is conserved in a closed reaction. What leaves the start flask shows up as product. The sum stays put. 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: Mass is conserved in a closed reaction. What leaves the start flask shows up as product. The sum stays put.
Before you begin: Read the controls for Moved to product. 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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