This lesson is designed for the NEW AQA Trilogy Chemistry GCSE, particularly the ‘Pure substances and mixtures’ SoW.
 
This lesson starts with a ‘Think > Pair > Share’ task on the differences between an element, compound and a mixture. Pupils will share their ideas as a class before definitions and a diagram for each is revealed on the PowerPoint presentation. The next task requires pupils to ‘Think > Pair > Share’ their ideas about what it means for a substance to be ‘pure’. Again, their ideas can be shared with the class before a definition of purity is revealed.
 
Next, pupils will complete an investigation into the purity of water - they will be provided with three unknown liquids and conducting a range of tests they will need to determine which one is pure water, which is sea water and which is mineral water. They will record their results in a table and then present their findings to the class.
 
Next, students are shown how chemists are able to analyse substances and determine whether they are pure or whether they are a mixture by determining their melting/boiling points, to see if it is at a fixed point or not. Pupils will then watch a video on this topic and will need to answer a set of questions, they can mark this work using the answers provided.
 
Pupils will then be shown two examples of common formulations - paint and cleaning product. Lastly, pupils will then complete a ‘Quick Check’ task - answering a set of questions on what they have learned this lesson. They will then mark their work using the answers provided.
 
The plenary task is for pupils to complete one of the sentence starters provided to summarise what they have learned this lesson.