Freezing Lab

From moving water to ordered ice

Learning modeStudent Mode

Mission: make ice

Lower the chamber temperature, press Start, and find the energy plateau where water changes state.

Experiment

Choose a guided setup

Chamber temperature−12 °C

Water mass150 g

Dissolved salt0%

Simulation speed1×

Live measurements

8.0 °Csample temperature

0%frozen fraction

0 kJheat removed

0.0 °Cfreezing point

The molecules are moving freely. The sample is above its freezing point.

Captured object

Water molecule

Temperature & ice formation

TemperatureFrozen fraction

Camera & tracking

Zoom1.00×

Drag the chamber to pan. Use the wheel or pinch to zoom. Tap a molecule, crystal, vessel, or thermometer to inspect it.

Teacher tools

Heat transfer strength1.0×

Interactive lecture

Step 1 of 100%

Ready — lecture will not start automatically.

1. What freezing means

What to watch: Watch the freely moving molecules.

Freezing is the change from a liquid to a solid when enough thermal energy leaves a substance.

Language & voice

Narration languageVoice sourceVoice

Chapters

Learning objectives

Relate temperature to average molecular motion.
Identify the freezing point and the phase-change plateau.
Explain why energy leaves while temperature stays nearly constant.
Predict how salt, sample mass, and chamber temperature affect freezing.
Connect crystal order to the properties of ice.

Key concepts

Cooling: Molecules lose kinetic energy and move more slowly.

Nucleation: A small ordered cluster starts a crystal.

Latent heat: During freezing, removed energy builds intermolecular structure instead of lowering temperature.

Freezing-point depression: Dissolved salt disrupts the formation of an ice lattice, lowering the freezing point.

Model note: temperatures and energy use measured physical units. Particle size, motion, vessel proportions, and process speed are conceptual visual scaling. Salt depression uses an educational approximation of 0.6 °C per 1% salt.

Suggested experiments

Set the chamber to −30 °C, then compare the freezing time with −5 °C.
Raise salt from 0% to 10% and watch the target freezing point move.
Compare 50 g and 300 g samples in the same chamber.
Pause during the plateau and step forward one second at a time.

Questions for exploration

Why does the graph flatten while more ice appears?
Where does the first stable crystal form in the vessel?
Does colder air change the freezing point, or only the rate?
Why does salt help keep winter roads from icing?

Applications & misconceptions

Applications: food preservation, ice making, cryopreservation, weather, and road safety.

Misconception: “Water loses all molecular motion when frozen.” Molecules in ice still vibrate.

Misconception: “Colder surroundings change pure water’s freezing point.” They change the rate; composition and pressure set the equilibrium point.

Freezing challenge

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