Lesson Plan

• Describe evaporation as the escape of high‑energy particles from a liquid surface.
• Explain how evaporation produces a cooling effect in the remaining liquid.
• Analyse the five main factors that influence the rate of evaporation.
• Compare and contrast evaporation with boiling in terms of temperature, location and energy requirements.

• Projector and screen
• Whiteboard and markers
• Printed handout with particle‑energy diagram
• Worksheet on factors affecting evaporation
• Shallow tray of water and a thermometer
• Small fan to demonstrate air movement
• Venn‑diagram template for evaporation vs. boiling

Ask students to picture a puddle that disappears on a sunny day and discuss why this happens. Recall the kinetic particle model they have learned previously, emphasizing that particles have a range of energies. State that by the end of the lesson they will be able to explain evaporation using this model and identify the factors that control its rate.

1. Do‑now (5 min): Students write a definition of evaporation and give a real‑world example.
2. Mini‑lecture with animation (10 min): Explain the particle‑model explanation of evaporation and show the kinetic‑energy distribution diagram.
3. Demonstration (8 min): Place a tray of water on the bench, record its temperature, then turn on a fan and note the temperature drop.
4. Guided inquiry (12 min): In pairs, students complete a worksheet analysing how temperature, surface area, wind, humidity and liquid nature affect evaporation.
5. Comparison activity (8 min): Groups fill a Venn diagram contrasting evaporation with boiling.
6. Exit ticket (5 min): Two short questions – one describing the cooling effect, one naming two factors that increase evaporation rate.

Summarise that evaporation is the loss of the most energetic surface particles, which cools the liquid, and review the key factors influencing its speed. Collect the exit tickets as a quick assessment and assign homework: investigate the evaporation rates of three different liquids and write a brief report linking the observed differences to intermolecular forces.