| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: Explain that distilled water is used in practical chemistry rather than tap water because it contains fewer chemical impurities |
Learning Objective/s:
- Describe why distilled water is preferred over tap water in laboratory experiments.
- Identify common impurities in tap water and their potential effects on chemical analyses.
- Explain how the distillation process removes impurities to produce pure water.
- Apply appropriate handling and storage practices for distilled water in the lab.
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Materials Needed:
- Projector or interactive whiteboard
- PowerPoint slides or printed handouts summarising water impurities
- Samples of tap water and distilled water (or images)
- Simple distillation apparatus (flask, condenser, collection vessel) for demonstration
- Beakers, pipettes, and cleaning brushes
- Worksheet for student activity
- Exit‑ticket cards
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Introduction:
Begin with a quick demonstration: pour tap water into a beaker and ask students what they notice. Recall that water is the universal solvent and that any dissolved substances can affect experimental results. Explain that today’s success criteria are to identify key impurities in tap water, describe how distillation removes them, and justify the use of distilled water in practical chemistry.
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Lesson Structure:
- Do‑now (5'): Students answer a short question on why water purity matters. (Check for understanding)
- Mini‑lecture (10'): Present common tap‑water impurities and their effects using slides.
- Demonstration (10'): Show a simple distillation apparatus and explain each step of the process.
- Group activity (15'): Students compare sample data sets (tap vs. distilled) and discuss the impact on experimental results.
- Whole‑class discussion (5'): Summarise the advantages of using distilled water.
- Exit ticket (5'): Each student writes one reason distilled water is essential for a chosen technique.
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Conclusion:
Recap that distilled water’s high purity ensures reliable and reproducible results, whereas tap water’s impurities can compromise experiments. Invite students to share one key takeaway on how specific impurities affect particular techniques. Collect exit tickets and assign a brief homework task: research another laboratory solvent that requires purification and explain why.
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