Lesson Plan

• Describe qualitatively how the length of a metallic wire influences its resistance.
• Explain how the cross‑sectional area of a wire affects its resistance.
• Predict the change in resistance when length or area is altered.
• Apply the qualitative relationships to solve simple physics questions.
• Communicate reasoning using correct scientific terminology.

• Projector and screen
• Whiteboard and markers
• Printed worksheet with summary table
• Sample copper wire and ruler
• Resistance measurement kit (optional)
• Exit‑ticket slips

Begin with a quick demonstration: connect a lamp to a battery through a short piece of copper wire, then replace it with a longer piece and observe the dimmer light.

Ask students what changed and link it to prior learning about current flow and resistance.

Explain that today they will articulate how length and cross‑sectional area qualitatively affect a wire’s resistance and be able to predict outcomes of simple changes.

1. Do‑now (5'): Students answer a prompt on the board about everyday examples of resistance (quick check).
2. Mini‑lecture (10'): Present qualitative relationships using diagrams and the summary table, prompting questions.
3. Guided inquiry (15'): Small groups use wire, ruler, and the resistance kit to test how doubling length or halving area changes brightness; record observations.
4. Class discussion (10'): Groups share findings; teacher reinforces direct and inverse proportionality concepts.
5. Application practice (10'): Worksheet with qualitative questions, including the example of doubling length.
6. Formative check (5'): Exit ticket – write one sentence predicting resistance change if length is tripled while area stays constant.

Summarise that resistance rises directly with length and falls inversely with cross‑sectional area.

Students complete an exit‑ticket to demonstrate understanding, and the teacher reviews responses.

For homework, assign a set of qualitative scenarios requiring a brief prediction of resistance changes.