Experiments with salt

Teacher notes

Pupils will begin to understand the concept of water density and how it is affected by the concentration of salt. They will do this in the form of a practical experiment after observing how people float more easily in the very salty water of the Dead Sea. Some activities for KS2 can be omitted for KS1. **Note:** We have not included a film in this lesson to allow more time for the experiment. However, showing the film 'Salty Shores' from Scene 1 of the storyworld shows how salt is extracted from the sea and also shows recreational visitors. If you have time, open and show the film at the end - perhaps pupils can ask scientific questions about floating humans in Dead Sea water! **Accessibility:** To make this more accessible for younger learners or those with SEND, take a multi-sensory approach and explore containers of salt before beginning. Ask: - What does salt look like? Grainy, white, tiny, etc - What about if we get salt wet - what happens to it? It sticks together and gets lumpy. You could also ask what it tastes like and share a few grains of salt to taste! **Equipment:** For the salt experiment you will need for each group or pair of pupils, as suits your needs: - table salt - water - a container (bowl or large drinking glass) - teaspoon - 1 fresh egg (fresh eggs will sink but older eggs float). Use room temperature water to dissolve the salt quicker. **National Curriculum objectives:** KS1 Science Pupils should: - ask simple questions and recognise that they can be answered in different ways, observing closely - use simple equipment and perform simple tests - use their observations and ideas to suggest answers to questions - gather and record data to help in answering questions. - describe the simple physical properties of a variety of everyday materials, eg floating/sinking. KS2 Science - compare and group together everyday materials based on their properties, including solubility and transparency - know that some materials will dissolve in liquid to form a solution, and describe how to recover a substance from a solution - use knowledge of solids, liquids and gases to decide how mixtures might be separated, including through filtering, sieving and evaporating - demonstrate that dissolving, mixing and changes of state are reversible changes - ask relevant questions and use different types of scientific enquiries to answer them - make systematic and careful observations and, where appropriate, take accurate measurements using standard units, using a range of equipment - record findings using simple scientific language, drawings, labelled diagrams, keys, bar charts, and tables - report on findings from enquiries, including oral and written explanations, displays or presentations of results and conclusions