Why does dye spread through water?
Add dye · Allow time · Wait longer
Why does dye spread through water?
Add a small amount of dye on the left. Concentration is higher there. Liquid and dye particles move constantly.
Particles move randomly in many directions. Overall, dye spreads from higher concentration towards lower concentration.
Over time the distribution becomes more uniform. Particles keep moving even after concentration evens out.
For adults · discuss together
Random-walk illustration, not real molecular trajectories. Stirring and convection are excluded.
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 ↗