Separation by Evaporation - Lesson Plan

In a comprehensive lesson plan focused on the topic of 'Separation by Evaporation,' students are expected to enhance their understanding of scientific concepts as they relate to mixtures and solutions. The lesson aligns with the National Curriculum, particularly addressing how knowledge of solids, liquids, and gases can be applied to separate mixtures using evaporation, among other methods. Students will learn to identify solutes and solvents within a solution, understand the process of evaporation, and explain how this process can be used to separate a solute from a solvent. Building on prior knowledge from previous years, such as identifying everyday materials and understanding states of matter, the lesson aims to correct common misconceptions, such as the nature of evaporation being a physical rather than a chemical change and the fact that it can occur at various temperatures, not necessarily requiring a lot of heat.

The lesson plan includes engaging activities where students will conduct experiments to observe the process of evaporation firsthand. They will use equipment like plastic cups, water, measuring cylinders, and cling film to set up an experiment to measure water loss over time, drawing on their maths skills to perform calculations with their results. Another activity involves using tealights, pie tins, salt, and a stopwatch to separate salt from water through evaporation, providing practical experience of the separation technique. Health and safety considerations are emphasised, especially when handling fire during the experiments. Ultimately, students will participate in a plenary session to consolidate their learning, answering questions about the components of a solution and the effectiveness of evaporation as a separation technique.