Use these student activities and teacher guide to investigate reusable and disposable hand warmers. You will compare reusable variants made with sodium acetate vs disposable handwarmers. You can also try making your own hand warmers. These activities may work well as a project on class topics like ‘winter’ or ‘body matters’ (extremities and keeping warm).

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Additional information

This resource was safety checked in September 2014 and last updated November 2015.

If you teach primary science, see the headings below to find out how to use this resource:

Skill development

Children will develop their working scientifically skills by:

  • Selecting and planning the most appropriate ways to answer science questions, recognising and controlling variables where necessary, including:
    • Carrying out comparative and fair tests.
  • Using appropriate scientific language and ideas to explain, evaluate and communicate their methods and findings.
  • Drawing conclusions and raising further questions that could be investigated, based on their data and observations.

Learning outcomes

Children will:

  • Know that some materials will dissolve in liquid to form a solution.
  • Compare and group materials on the basis of their properties (conductivity – thermal).
  • Give reasons for the particular uses of everyday materials.

Concepts supported

Children will learn:

  • That some substances can be dissolved in liquids, and that when a solute dissolves it doesn’t ‘disappear’.
  • There are several factors that contribute to how substances dissolve.
  • That dissolving is a reversible process.
  • Not all substances can dissolve.

Suggested activity use

This resource could be used as a whole-class investigation with older children, observing differences and similarities with hand warmers leading to research on how they work. Children can investigate why materials have been chosen for the hand warmers, linking to previous knowledge on materials and properties.

The investigation into solubility leads nicely into setting up a fair test, considering variables and conclusions.

Practical considerations

If not carefully managed, the misconception that a solvent can dissolve an unlimited amount of solute, i.e. that there is no saturation point, can be introduced or reinforced.

How hand warmers work will need to be explained and explored by children before starting the investigations.

Various equipment and resources will need to be sourced prior to the lesson, including sodium acetate and a range of different types of hand warmers.

As with all investigations, a thorough risk assessment needs to be completed and other health and safety considerations need to be taken into account.