– represent what happens when a solid melts.
Reflect on the frozen milk, melted chocolate and melted ice poles. What did they look like?
Looking at a frozen ice pole and the melted ice pole.
Are these the same object? Why/ Why not?
Are these made of the same things?
How do we get one from the other?
What are the similarities between these items?
What are the differences between these items?
The term ‘substance’ and ‘particle’
Substances change state when they gain or lose heat energy. For example, frozen water that gains heat energy will start to change into a liquid at 0 degrees, and liquid water will start changing into water vapour (gas) at 100 degrees.
Scientists think that particles in a solid like a frozen ice pole are all packed together and only wobble around a fixed position, whereas in a liquid, they have more energy and can mover more freely and slide over each other. When the particles gain heat energy they move more energetically.
Use the idea of particles to represent what they think is happening when an ice cube melts.
Role Play 1: Represent what happens to the particles in a melting ice cube. Particles are very tightly packed together in solid state start to move faster and move past each other.
Role Play 2: Represent being particles of water. In this role play the particles will have low energy and so are not moving much and are all packed together.
Role Play 3: Represent ‘adding heat energy’ to students by tapping them on the shoulder.
Role Play 4: Introduce a tray filled with marbles or small beads. The marbles will represent the particles of water.