Solar evaporation and salt extraction give Grade 6 Science students a real-world example of how mixtures can be separated using differences in physical properties. Using salt production in Sri Lanka’s Puttalam District, this worksheet explores how sunlight and wind help remove water from seawater or lagoon water, leaving salt crystals behind.

🌞 From Seawater to Salt Crystals

Students begin with a reading passage describing how workers use shallow ponds called salterns to produce salt. The example draws on a 2019–2020 report from Raigam Wayamba Salterns PLC and connects the science of separation to a local production process. Students examine how salt dissolves in water, how evaporation concentrates a solution, and why salt remains behind when water changes into vapour.

The passage also introduces the effect of local weather conditions. Students consider why dry weather supports salt production while heavy rainfall can slow the process. This provides a practical context for discussing solubility, evaporation, solutions and physical properties.

🔬 What Students Practise

The activities move from reading and identifying scientific information to applying it through explanations and investigation tasks. Students work with:

• Multiple-choice questions about salterns, dissolved salt, evaporation, weather conditions and scientific sources.
• True-or-false statements that check understanding of solutions and the solar evaporation process.
• Short-answer explanations of how salt is collected and which physical properties make separation possible.
• A fair-test investigation prompt about the effect of wind on evaporation.
• A labelled diagram activity and a categorisation task to reinforce the topic.
• A short note activity for consolidating key information.

Scientific investigation skills are part of the learning too. Students consider how to observe, measure, compare and record results, test the influence of environmental conditions, and use reliable sources rather than assuming one local example applies everywhere.

📦 What Is Included

• ✔️ Solar Evaporation and Salt Extraction student worksheet
• ✔️ Separate PDF answer key for checking student responses
• ✔️ Student Notes lines at the bottom of the worksheet
• ✔️ Teacher Guide within the answer key PDF, with Learning Objectives, Teaching Tips, Discussion Questions and Common Mistakes

🏫 Classroom Use

Use this Grade 6 mixtures and separation worksheet during a lesson on separating dissolved substances, as guided reading followed by independent practice, or as a review of physical properties and changes of state. The Puttalam salt-production example also gives students a meaningful starting point for classroom discussion about how scientific processes are used in local industries.

The separate answer key makes checking work more straightforward, while the accompanying teacher guidance provides preparation support and discussion prompts. Students can finish by recording additional observations or key ideas in the notes space provided.

A practical resource for teaching solar evaporation, solubility and separation of mixtures through a recognisable Sri Lankan example.