Does everything always dissolve?
Small portion · Add more · Excess substance
Does everything always dissolve?
Add a small portion to a fixed water volume at constant temperature. It all dissolves.
Add more. Here the solution reaches saturation: it contains its maximum amount of this substance under these conditions.
Excess stays on the bottom. Stirring speeds dissolution but by itself does not increase equilibrium solubility.
For adults · discuss together
An illustrative substance with a limit of 12 particles. Constant temperature; not a numerical model of a particular salt.
Before experience
Ask: “What do you think will happen?” Let the child check his guess first.
After the experience
What has changed? What remains the same? Where can you notice a similar phenomenon?
Ready for another discovery?
What changes when things heat up?
Explore particles in a solid, a liquid and a gas.
Explore ↗Ages 12–16
Where do atoms go in a reaction?
Make water molecules from hydrogen and oxygen. Count the atoms.
Explore ↗10–16 years
Where do atoms go in a reaction?
Starting molecules · Rearrange · Count the atoms
Explore ↗