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Change of State

States of matter game: solid, liquid and gas

ChemistryPrimary, Secondary, Sixth Form
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A chemistry game to finally break the idea that solid means cold and gas means hot. You get a substance and a temperature, and you say what state it is in. There are three levels. On the first two the melting and boiling points are on screen and there is nothing to memorise: you just read where that temperature falls relative to the two points of THAT substance. On hard they are hidden, so you have to know the substance, and they appear when the answer is revealed. There are 30 real substances, from metals to gases, and on answering you see the particles for that state: ordered and still in a solid, loose in a liquid, flying in a gas.

Chemistry · Primary, Secondary, Sixth Form

🧠 Pedagogical Benefits

State is relative, not absolute

Iron at 1000 °C is red hot and still solid; oxygen at 20 °C has been a gas for 200 degrees. Hot and cold are our labels: what decides the state is the distance to each substance's own points.

Reading a scale, not memorising it

On the first two levels the melting and boiling points are on screen on purpose. The skill trained is placing a value between two thresholds — the same one needed to read a graph, a thermometer or a data table in any subject.

One thing, many times

The game asks a single question and repeats it across 30 different substances. That insistence is what turns the rule into an automatism, instead of splitting attention between several mechanics in one session. And since the temperature is drawn at random each round, the same substance never asks the same thing twice: the answer cannot be learnt by heart.

💡 Practical Example

"Up comes "Mercury, 20 °C", with its points: melts at −39, boils at 357. Many answer solid because they think "metal". Once they see 20 sits between the two, the answer follows: liquid — along with the explanation of why mercury was the thing inside old thermometers."

📝 States on paper

Prefer to learn without screens? Try this analogue version:

  1. 1

    Draw a line with a substance's two points marked and its three zones.

  2. 2

    Call out random temperatures and have the zone pointed at before the state is named.

  3. 3

    Repeat with an odd substance (mercury, oxygen) and compare the two lines.

  4. 4

    Finally, write the six changes of state with a household example for each.

🖨️ Ready-to-print materialCards already written, ready to cut out: history, geography, chemistry and more. Free, no sign-up.→

🎲 Similar activities you might enjoy

If you like Change of State, these activities work similar skills:

The glass of ice

Put ice in a glass and watch three things at once: ice melting, liquid water, and mist condensing outside. Three changes of state in one glass.

The table of points

Look up melting and boiling points for ten substances and order them. Seeing helium at −269 and iron at 1538 in one table says more than any explanation.

Hunt changes of state at home

For one day, note every change of state you see: clothes drying, a fogged mirror, an ice cream melting. Naming them on the spot is what fixes the vocabulary.

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