Learning Objective: 3.4 Applying Pascal’s Principle

Method: Inquiry-Discovery

Approach: Set Induction

Activity: Hands-on (predict, observe , explain)

List of material/apparatus: Toothpaste, plastic bag, simple hydraulic system

Activity 11. How do you push the toothpaste out from the toothpaste

tube?

Activity 21. Perforate a plastic bag with a needle2. Fill in water into the plastic bag3. Press the plastic bag

Idea: Pressure exerted on an enclosed liquid is transmitted equally to every part of the liquid.

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Activity 3

1. Each table is equipped with a simple hydraulic system as shown on the diagram below.

2. Students are asked to observe piston B when piston A is pressed.

3. Student presses Piston A.

4. Students are asked to explain their observation.

Activity 41. Student now presses both Piston A and Piston B so that both are in equilibrium.

2. Students are asked about the piston that requires a larger force.

3. Students are asked about pressures acting on both pistons.

4. Students are asked to relate the pressure, P1, on piston A in terms of force, F1 and area, A1

5. Students are asked to relate the pressure, P2, on piston B in terms of force, F2 and area, A2

6. Students are asked to derive a relationship between F1, F2, A1, and A2.

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Summative Test Questions

1. The pressure applied to an enclosed liquid is ……………….. transmitted to all parts of the liquid.

2. Why does the presence of air bubbles in hydraulic brake system will cause the system to be less efficient?

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

3. The figure below shows a model of a simple hydraulic system.

The cross-sectional area of piston X is 0.03 m2 and the cross-sectional area of piston Y is 0.90 m2. Calculate the weight of object P?

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