Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: Know the melting and boiling temperatures for water at standard atmospheric pressure
Learning Objective/s:
  • Describe the melting (0 °C) and boiling (100 °C) points of water at 1 atm.
  • Explain why temperature remains constant during melting and boiling.
  • Calculate the heat required for a given mass of ice to melt or water to boil using latent heat values.
  • Predict how a change in external pressure would shift the boiling point.
  • Interpret a phase‑change diagram for water.
Materials Needed:
  • Projector or interactive whiteboard
  • PowerPoint slides with phase‑change diagram
  • Ice cubes and hot plate (demo)
  • Thermometer or digital temperature sensor
  • Worksheet with calculation problems
  • Calculator
  • Exit‑ticket cards
 Introduction:
Begin by asking students why water always boils at 100 °C at sea level. Review their prior knowledge of the Celsius scale and the three states of matter. State that by the end of the lesson they will be able to name the exact temperatures for melting and boiling, explain the energy changes involved, and apply these ideas to simple calculations.
Lesson Structure:
  1. Do‑Now (5') – Quick quiz on states of matter and Celsius temperature points.
  2. Mini‑lecture (10') – Present melting and boiling points, standard atmospheric pressure, and a phase‑change diagram.
  3. Demonstration (10') – Melt ice and boil water while monitoring temperature; discuss the temperature plateaus and latent heat.
  4. Guided practice (12') – Worksheet problems calculating heat for melting 250 g of ice and boiling water.
  5. Concept check (8') – Think‑pair‑share: Why does temperature not rise during a phase change?
  6. Extension (5') – Brief discussion on how reduced pressure lowers the boiling point.
  7. Exit ticket (5') – Students write the two temperatures and one reason for constant temperature during phase change.
Conclusion:
Recap the melting and boiling temperatures and the role of latent heat in keeping temperature steady during phase changes. Collect exit tickets to gauge understanding, and assign a short homework set of additional heat‑calculation problems. Encourage students to observe real‑world examples of pressure affecting boiling points (e.g., mountain cooking).