Lesson Plan

• Recall the definition of pressure (p = F/A) and its unit, the pascal.
• Derive and state the hydrostatic pressure formula Δp = ρ g Δh.
• Apply the formula to calculate pressure increase for given depths and liquids.
• Convert Δp to atmospheres or other convenient units.
• Explain real‑world implications such as why dams are thicker at the base.

• Projector and screen
• Whiteboard and markers
• Scientific calculators (one per student)
• Worksheet with practice questions
• Printed diagram of a liquid column showing Δh and Δp
• Handout of typical liquid densities

Begin with a quick demonstration of a water column to show how pressure increases with depth, sparking curiosity about why dams are shaped the way they are. Review the basic pressure definition and units that students already know from earlier lessons. Explain that by the end of the lesson they will be able to calculate pressure changes in any liquid and relate the results to real‑world situations.

1. Do‑now (5'): Students answer a short question on pressure definition and units on the board.
2. Mini‑lecture (10'): Derivation of Δp = ρ g Δh using the slab example; introduce each variable and typical values.
3. Guided practice (10'): Work through the provided worked example (5 m depth in fresh water) together.
4. Independent practice (15'): Students complete the three practice questions on the worksheet while the teacher circulates for support.
5. Concept check (5'): Quick quiz (clickers or show of hands) on common mistakes such as using the wrong g value.
6. Summary & reflection (5'): Review the checklist, ask a few students to explain why a dam must be thicker at the base.

Recap the key steps for using the hydrostatic pressure equation and highlight how to convert results to atmospheres. For the exit ticket, each student writes one everyday example where hydrostatic pressure is important. Homework: complete the additional set of pressure‑change problems in the textbook.