| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Chemistry |
| Lesson Topic: State that some of these substances are beneficial, including: (a) dissolved oxygen for aquatic life (b) some metal compounds provide essential minerals for life |
Learning Objective/s:
- Describe the role of dissolved oxygen in supporting aquatic life and overall water quality.
- Explain why trace metal ions are essential nutrients for organisms and the importance of maintaining safe concentration limits.
- Analyze the interaction between dissolved oxygen and metal‑ion redox reactions in natural waters.
- Interpret dissolved‑oxygen saturation tables and metal‑ion data to assess water‑quality conditions.
- Evaluate simple monitoring strategies for beneficial substances in freshwater systems.
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Materials Needed:
- Projector or interactive whiteboard
- Printed handouts with DO saturation table and metal‑ion chart
- Sample water‑quality data sheets
- Calculator
- Whiteboard and markers
- Dissolved‑oxygen meter (optional for demonstration)
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Introduction:
Imagine a river teeming with fish, insects, and plants—all thriving because the water contains the right amount of oxygen and essential minerals. Students will recall previous lessons on water as a universal solvent and discuss what “beneficial” substances might look like. Success criteria: students will be able to identify and explain the importance of dissolved oxygen and trace metals in water quality.
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Lesson Structure:
- Do‑Now (5') – Quick quiz: Why is water called the “universal solvent” and what does this imply for dissolved substances?
- Mini‑lecture (10') – Dissolved oxygen: Henry’s law, temperature‑saturation table, and its ecological importance.
- Guided analysis (10') – Pairs interpret DO data for different temperatures and discuss potential impacts on aquatic life.
- Mini‑lecture (10') – Essential metal ions (Ca²⁺, Mg²⁺, Fe²⁺/Fe³⁺, Zn²⁺, Cu²⁺): biological roles and typical water sources.
- Group activity (10') – Create a poster summarising each metal’s function and safe concentration range.
- Demonstration & discussion (10') – Redox interaction (Fe²⁺ oxidation) and its effect on DO levels; students predict outcomes.
- Check for understanding (5') – Exit ticket: one short answer describing how a change in metal redox state can affect dissolved oxygen.
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Conclusion:
We reviewed how dissolved oxygen and trace metals support aquatic ecosystems and how their concentrations are monitored. For the exit ticket, students write one way a change in metal redox state can influence DO levels. Homework: analyse a provided water‑quality dataset and identify any potential concerns regarding oxygen or metal concentrations.
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