Charles Law Lab 3D

Heat and cool a flexible balloon at constant outside pressure

Paused • 3.00 L

Drag the balloon up or down to heat or cool • Drag background to pan • Wheel or pinch to zoom

Mission: discover the direct relationship

Keep pressure and gas amount fixed. Heat the gas and observe how the balloon membrane and volume respond.

Simulation speed1×

Gas controls

Volume3.00 L

Temperature300 K

Hold pressure constant for Charles Law

83.1constant P kPa

0.0100V ÷ T L/K

—wall hits / s

At 300 K the gas occupies 3.00 L. Heating makes molecules move faster, so the flexible balloon boundary rises until internal pressure again matches the constant external pressure.

Quick experiments

Prediction: if kelvin temperature rises by 50% at constant pressure, volume should also rise by 50%.

Temperature–volume evidence

PressureV ÷ T● current state

Tracked object

No object selected

TipTap balloon membrane or molecule

Camera

Zoom100%

Teacher controls

Gas amount0.100 mol

Show force and collision labels

Teacher-guided complete Charles’s law lecture

Language

Voice source

Voice

Narration speed1×

Ready0%

What to watch: the heater, molecular speed, rising balloon membrane, volume scale, and graph.

Choose a language and voice, then start the complete lecture. Every chapter controls heating, cooling, molecular motion, balloon size, and the graph on the canvas.

Ready. Narration will not start automatically.

Chapters

Learning objectives

Describe the direct relationship between kelvin temperature and gas volume.
Use V₁ ÷ T₁ = V₂ ÷ T₂ for a fixed gas amount at constant pressure.
Explain expansion using faster molecular motion and a flexible balloon boundary.
Read a volume–temperature graph and identify absolute zero by extrapolation.
Apply Charles’s law to balloons, hot-air balloons, and flexible containers.

Key concepts demonstrated

Kelvin temperature

Temperature measures average molecular kinetic energy. Calculations must use kelvin, not Celsius.

Volume

The highlighted space below the freely moving balloon membrane expands when the gas is heated.

Constant pressure

The flexible balloon membrane moves until gas pressure matches the fixed external pressure.

Constant ratio

For fixed gas amount and pressure, volume divided by kelvin temperature remains constant.

Plain-language explanation

Heating increases average molecular speed. Molecules strike the flexible balloon boundary harder and more frequently, lifting it. Expansion continues until internal pressure again balances the constant external pressure. Cooling slows molecules and the balloon membrane moves downward.

Scientific model: volume is calculated from V = nRT ÷ P. Particle number, size, and drawn speed are conceptual visual scaling; temperature, pressure, and volume readouts follow the ideal-gas model.

Suggested experiments

Compare 300 K with 450 K and check whether volume rises by 50%.
Record V ÷ T at five temperatures.
Switch between heating and cooling and follow the red graph point.
Use Celsius mentally, then notice why kelvin is required.

Questions for exploration

Why must the balloon membrane move for pressure to remain constant?
What volume is predicted near absolute zero?
What changes if the external pressure increases?

Real-world applications

Warm balloon: flexible walls allow heated gas to occupy more volume.
Hot-air balloon: heating expands air; an open envelope lets some air leave, lowering density.
Weather balloon: temperature and outside pressure both affect size, so Charles’s law alone is an approximation.
Baking: heated gas bubbles expand and help dough rise.

Common misconceptions

Molecules do not grow; their average speed and spacing change.
Charles’s law requires constant pressure and a flexible boundary.
Celsius temperature cannot be used directly in proportional calculations.
Absolute zero is an extrapolated ideal-gas limit, not a temperature reached here.

Score: 0 / 7