Rock salt is the name given to salt before it is processed.

Rock salt is a brown colour and looks like gravel, so it is often referred to as grit.

To melt is to change from a solid state to a liquid state.

In a comparative test, the thing that is being changed has labels, such as the types of materials.

Variables are the things that can be changed, measured or kept the same in a comparative test.

The effect of adding salt to ice: plan (non-statutory)

Science

In the Materials Challenge unit, pupils learn how to separate materials using different techniques, such as filtering and evaporation. In the Solutions unit, they will build upon this knowledge to learn about pure substances and mixtures, as well as observing and explaining solubility using the particle model.    

In the Properties, changes and separating materials unit, pupils learnt to decide how mixtures might be separated, including through filtering, sieving and evaporating. In this Materials challenge unit, they will build on this knowledge to apply their understanding of separating materials to a wider range of everyday situations

This unit covers separating materials using techniques such as filtering and evaporation. It focuses on planning scientific enquiries, recognising and controlling variables, taking accurate measurements, recording complex data, and presenting findings with conclusions, and explanations.

Materials (non-statutory)

Physical activity and equipment requiring safe use

Where is rock salt often stored so it can be used on our roads and pavements?

After being mined, but before it can be transported to grit bins, rock salt has to be ...

Variables can be changed in an investigation.

Variables cannot be changed in an investigation.

Variables can be measured in an investigation.

Variables cannot be measured in an investigation.

Variables can be kept the same in an investigation.

Which variable is changed in an investigation to find out which type of salt melts ice the fastest?

What kind of salt do people usually put on their food?

Rock salt is the name given to salt before it is sold in a shop.

Rock salt is the name given to salt before it is mined.

What are the main ways in which can table salt be obtained?

Which pieces of equipment would be useful to observe different types of salt?

something that can be changed in an investigation 

something that can be measured in an investigation 

something that can be predicted in an investigation 

something that can be recycled in an investigation 

something that can be kept the same in an investigation 

Content guidance

Risk assessment required - equipment

Adult supervision required

Introduction

What will you need for this lesson?

Are you ready to learn?

Equipment

Content guidance

Supervision

Worksheet