Gas Laws - Boyle's, Charles' and Combined Gas Laws

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Subject: Physics

Semester: 2

Period: 4

Week: 23

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School Name:

Teacher’s Name:

Subject: Physics

Grade Level: Grade 10

Week & Period: Week 23, Period IV

Date:

Sub-topic: Gas Laws – Boyle’s, Charles’, and Combined Gas Laws

Learning Objectives:
By the end of the lesson, learners should be able to:

1. State and explain Boyle’s, Charles’, and the Combined Gas Laws.
2. Derive and apply the equations for each law.
3. Solve numerical problems involving pressure, volume, and temperature.
4. Describe how the gas laws relate to real-world phenomena.

Instructional Materials:

• Gas syringe
• Pressure pump or hand pump
• Balloons
• Ruler and stopwatch
• Bunsen burner / heat source
• Ice water bath
• Sealed transparent containers
• Thermometer
• Manometer

Anticipation (Warm-Up):
Ask: “Why do balloons expand when heated and shrink in the cold?”
Show a balloon in cold and warm water to spark curiosity.

 

Building Knowledge:

1. Boyle’s Law – At constant temperature, the pressure of a gas is inversely proportional to its volume:

P∝1V⇒PV=constant

• If P1V1=P2V2 , then pressure and volume changes can be computed.
• Example: A gas has pressure 100 kPa and volume 2 L. What is the new volume if pressure is increased to 200 kPa?

 

 

Experiments:

1. Boyle’s Law Demonstration:
   • Apparatus: Syringe, weight, pressure sensor (optional)
   • Procedure:
     Trap air inside syringe and seal it.
     b. Apply pressure and measure change in volume.
     c. Plot Pressure vs 1/Volume graph.
   • Expected Result: A straight line, confirming PV=constant
2. Charles’ Law Demonstration:
   • Apparatus: Balloon, boiling water, ice bath
   • Procedure:
     Place balloon in cold water – observe shrinkage.
     b. Move to warm water – observe expansion.
     c. Link to volume change with temperature.

 

Activities:

• Solve numerical problems using each gas law.
• In groups, design a chart summarizing all three gas laws with formulae and applications.
• Perform experiments with syringes and balloons to observe gas behavior.

 

Assessment:

1. State Boyle’s Law and give the mathematical expression.
2. A gas occupies 5 L at 25°C and 100 kPa. What volume will it occupy at 50°C and 200 kPa? (Use Combined Gas Law)
3. If 2 L of gas at 300 K becomes 3 L, what is the new temperature?

Homework:

• Define all three gas laws with one practical application for each.
• Complete 5 numerical problems involving all laws.

 

Expanded Notes:

• Boyle’s Law applies when temperature is constant: e.g., deep sea diving and syringes.
• Charles’ Law applies when pressure is constant: e.g., hot air balloons.
• Combined Gas Law is the most versatile: use when multiple factors change.
• Always convert temperature to Kelvin in calculations.

 

Differentiation:

• Use animated simulations for abstract learners.
• Offer formula cards to memory-challenged learners.
• Conduct peer tutoring during problem-solving sessions.

 

Teacher’s Reflection:

• Did learners understand how each law applies in real life?
• Were they able to correctly use and rearrange formulas?
• Do they need more practice on identifying which law to apply?