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InkFlaskCambridge IGCSE

Physical and chemical changes

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What this model shows

The waits are shortened: a few minutes of heating take about 20 seconds, and the tubes cool in a few seconds.

Stopping is one step here. The limewater tube moves down off the delivery tube before the flame goes out: as a hot tube cools, the gas inside it shrinks and would draw cold limewater back into the hot glass.

The green powder sold as copper(II) carbonate is a mixture of copper(II) carbonate and copper(II) hydroxide, so real tubes also give off a little water. The magnifier’s particles are a model, not to scale.

With reduced motion, each step finishes at once.

Select a piece of equipment, on the bench or here, to read about it in the card.