Set up time:
10 mins

What you need
Clear plastic drink bottles (1L or more), aluminium cans, black paint, thermometers, cardboard, aluminium foil, scissors, water

Aim
To demonstrate how pasteurisation works, and to show that the energy from the sun can be used for the pasteurisation process.


Learning outcomes

1

Your students will predict and record the effects of using solar energy to heat water.

2

Your students will read and record accurate measurements using a thermometer.

3

Your students will theorise on how a scientific experiment could be modified to obtain different results.


Worksheets

Solar pasteuriser


Instructions

Discuss the term ‘pasteurisation’, and how we can use the energy of the sun to heat liquids rapidly.

Following the instructions on the Solar pasteuriser worksheet, students can work in small groups to build the pasteurisers.

Students should record and compare water temperatures for their pasteurisers – with and without solar heating.

This experiment demonstrates the benefits of solar energy on a small scale. Discuss how the principles can be applied on a large scale.


This experiment uses a renewable energy source (the sun). What energy source do you think factories use for pasteurisation processes?
What other changes or modifications to this experiment could you make to test the effectiveness of solar energy?

Extension: Solar possibilities

In the activity above, students saw how solar energy can be used to heat up water. But what about cooking food? Can we capture enough heat energy from the sun to cook a pizza?

How to Turn a Pizza Box into a Solar Oven

1

An empty pizza box and a few other materials can be converted into a solar oven, capable of heating up foods.

2

In this makeshift solar oven, what are the most important elements, and how are they used to increase the heat in the ‘oven’.

3

By using stronger materials than those used in this video, do you think you could reach much higher temperatures and cook a roast lamb?

4

Discuss the pros and cons of using a solar oven to cook food with. Talk about things like the cooking time, greenhouse gas emissions, safety and so on.