Lesson: How Food Changes - Heating and Dissolving


Aims: To illustrate how food changes (i) from solid to liquid when heat is applied and (ii) how food can dissolve.

Objectives: To teach children the following language: "Liquid, Solid, Melt, Dissolve". To question the children so they will predict what will happen.

Materials Needed

Foods: Butter, Chocolate, Cheese, Ice-Pop, Salt, Sugar, Coffee and Sand.
Equipment: Saucers and Glasses.
Digital Camera





I will take the children in groups of 6 to the staffroom. On each saucer I will put a small amount of cheese, chocolate, butter and ice-pop. Into each glass I will put some salt, coffee, sugar and sand. Through questioning (e.g. What are these? Can I pick them Up? Can I pick up the water? What will happen?) words such as "spill", "pour", "flow" and "melt" are introduced. Pictures of these solids are taken at this stage before heat is applied.


Development - Changing Solids to Liquids

How could I change these solids? (by heating). We will use the microwave to illustrate this with some of the solids. We will add hot water to the other solids in the glasses.

Questions: How have solids changed? Why? What has happened to the sugar? Has it changed - disappeared? It has dissolved. What has happened to the cheese, butter etc? Have they changed? They have melted - become a liquid. What has happened to the sand? Has it changed?

Conclusion/Follow Up Activities

We will use the digital camera to take photos of the food items after they have changed. We will discuss the change from solids to liquids (before and after) using the pictures to revisit the concepts learned.

Back to Lesson Back to Class