Lesson Plan

• Describe the purpose and advantages of temporary (wet) preparations for microscopic observation.
• Demonstrate the correct step‑by‑step procedure for preparing a wet mount, including staining techniques.
• Calculate total magnification and select appropriate objective lenses for observing cellular structures.
• Identify common errors (air bubbles, over‑staining, specimen movement) and apply strategies to avoid them.

• Compound light microscope with 4×, 10×, 40×, 100× objectives
• Glass slides and cover slips
• Dissecting needles, tweezers, scalpel
• Distilled water, saline solution
• Staining solutions (iodine, methylene blue, carmine)
• Lint‑free tissue or paper towels
• Petroleum jelly (optional for sealing)

Begin with a short video showing live cells moving under a microscope to spark curiosity. Ask students what information is lost when cells are fixed and why observing living cells is valuable. Explain that today they will master making wet mounts and will be assessed on correctly preparing and interpreting a sample.

1. Do‑now (5'): Students label parts of a microscope on a worksheet.
2. Mini‑lecture (10'): Review purpose of wet mounts and safety rules.
3. Demonstration (15'): Teacher prepares a wet mount of onion epidermis, highlighting each step.
4. Guided practice (20'): Students work in pairs to prepare their own wet mounts using cheek cells, following a checklist.
5. Observation & recording (10'): Students use low power then increase magnification, note structures, and calculate magnification.
6. Peer review (5'): Pairs exchange slides, check for air bubbles and correct staining.
7. Formative check (5'): Quick quiz via Kahoot on common pitfalls and magnification formula.

Recap the key steps of a wet‑mount preparation and the importance of careful technique. Students complete an exit ticket describing one error they might encounter and how to correct it. For homework, they photograph a prepared slide and write a brief report linking observed structures to cell theory.