Do the gas particles really only wobble?

No, and that is the honest limit of this. A real gas particle crosses its container and bounces off the walls, which would mean positions changing sixty times a second and so nothing a shared link or an undo could describe. What the tool shows is the relative freedom of the three states, which is the part of the model a primary class is being taught: a solid on the spot, a liquid further, a gas furthest and fastest.

Why is exactly 0 °C shown as a liquid?

Because a tool with one arrangement to draw has to pick, and picking the warmer one keeps it consistent with "it melts at 0 °C", which is the sentence a class is given. At exactly 0 degrees ice and water sit together and neither has finished becoming the other, which is worth saying out loud.

Why does the temperature jump when I change substance?

It keeps the STATE rather than the number. Keeping the number would send every substance to room temperature, where three of the four are in the same state and the comparison the control exists for disappears.

Can I add my own substance?

Not yet. The four here cover what the unit needs: one of each at room temperature, plus water. A field for a melting point would need a keyboard, and a teacher at a board has a finger.

Solids, Liquids and Gases

Science · Year 4–Year 6

Heat it past melting and boiling, and watch the particles change.

Loading…

About the states of matter

Drag the temperature and watch what the particles do. Past the melting point the block comes apart; past the boiling point it fills the container. This is the Year 4 unit, and the one topic most classes are shown a video for, because what is being taught is what the particles DO and a still picture cannot show it.

The three arrangements carry the science. A solid is a neat block standing clear of the walls, because it keeps its own shape. A liquid lies across the whole floor to a level, because it takes the shape of its container. A gas is everywhere. That is the grouping objective drawn three times, and the block sitting clear of the walls matters as much as the spacing.

A solid's particles vibrate on the spot. A liquid's slide about further. A gas's go furthest. None of them ever touch each other or leave the container, at any temperature.

Everything moves faster as it warms up, in every state, which is the one thing kinetic theory says that a primary class can see. Water at 95 degrees is the same liquid as water at 5 and its particles are not doing the same thing. Stop stops all of it, for when you want the diagram from the book to annotate rather than something moving behind a class you are talking to.

Water is the default, because ice, water and steam being one substance in three states is the thing a class has to connect. Oxygen, mercury and aluminium are there for the other half of it: at room temperature one is a gas, one is a liquid and one is a solid, and each has its own melting and boiling point marked on its own scale.

Hide the state and the board gives the temperature but not the answer. The class reads the particles.

How to use it on your whiteboard

1Drag the marker up the scale to heat it, or tap the scale where you want it.
2The buttons do the same, a step at a time, and 20 °C goes back to room temperature.
3Substance switches between water, oxygen, mercury and aluminium. The scale relabels itself: each has its own melting and boiling point.
4Stop freezes the particles where they are, for a diagram to talk over.
5Hide takes the state names away, so the class works it out from the particles.
6Tap Fullscreen to fill the board.

Questions

Do the gas particles really only wobble?: No, and that is the honest limit of this. A real gas particle crosses its container and bounces off the walls, which would mean positions changing sixty times a second and so nothing a shared link or an undo could describe. What the tool shows is the relative freedom of the three states, which is the part of the model a primary class is being taught: a solid on the spot, a liquid further, a gas furthest and fastest.
Why is exactly 0 °C shown as a liquid?: Because a tool with one arrangement to draw has to pick, and picking the warmer one keeps it consistent with "it melts at 0 °C", which is the sentence a class is given. At exactly 0 degrees ice and water sit together and neither has finished becoming the other, which is worth saying out loud.
Why does the temperature jump when I change substance?: It keeps the STATE rather than the number. Keeping the number would send every substance to room temperature, where three of the four are in the same state and the comparison the control exists for disappears.
Can I add my own substance?: Not yet. The four here cover what the unit needs: one of each at room temperature, plus water. A field for a melting point would need a keyboard, and a teacher at a board has a finger.