Charles's Law with a Balloon

Measuring volume changes of a gas with temperature

Gas Laws Beginner (Middle School) 30 min ~$5.00

Objective

Demonstrate Charles's law by measuring the circumference of an air-filled balloon at different temperatures.

Background

Charles's law states that at constant pressure, the volume of a gas is directly proportional to its absolute temperature (Kelvin). By heating and cooling a balloon and measuring its size, the linear relationship between V and T can be confirmed.

Safety Warnings

  • Handle hot water carefully
  • Do not use boiling water directly on the balloon

Required PPE

goggles

Materials

  • Latex balloons (3)
    Same size
  • String (1 m)
    For measuring circumference
  • Ice (1 kg)
  • Hot water (2 L)
    Various temperatures

Equipment

Large containers (3) Thermometer Ruler or tape measure Timer

Procedure

1

Inflate a balloon to a moderate size and tie it off. Measure its circumference at room temperature with string.

3 min
2

Prepare three water baths: ice water (~5°C), room temperature (~22°C), and hot water (~60°C).

5 min Handle hot water carefully
3

Submerge the balloon in ice water for 5 minutes. Remove and quickly measure circumference. Record temperature.

7 min
4

Return the balloon to room temperature water for 5 minutes. Measure circumference.

7 min
5

Submerge in hot water for 5 minutes. Measure circumference. Record temperature.

7 min
6

Convert temperatures to Kelvin. Plot V (proportional to circumference³) vs T(K). Extrapolate to find absolute zero.

5 min

Expected Results

The balloon should be visibly smaller in ice water and larger in hot water. Plotting estimated volume vs absolute temperature should give a straight line. Extrapolating to zero volume should approximate -273°C (absolute zero).

Cleanup

Drain water baths. Pop and dispose of balloons. Clean up any spills.

Details

Category
Gas Laws
Difficulty
Beginner (Middle School)
Duration
30 min
Est. Cost
$5.00
Steps
6
Materials
4

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Frequently Asked Questions

What is the objective of Charles's Law with a Balloon?
Demonstrate Charles's law by measuring the circumference of an air-filled balloon at different temperatures.
How difficult is Charles's Law with a Balloon?
This experiment is rated as Beginner (Middle School). It takes approximately 30 minutes to complete.
What safety precautions are needed for Charles's Law with a Balloon?
Key safety precautions include: Handle hot water carefully; Do not use boiling water directly on the balloon.
What materials are needed for Charles's Law with a Balloon?
The main materials required are: Latex balloons, String, Ice, Hot water.
What results should I expect from Charles's Law with a Balloon?
The balloon should be visibly smaller in ice water and larger in hot water. Plotting estimated volume vs absolute temperature should give a straight line. Extrapolating to zero volume should approximate -273°C (absolute zero).