Heat & Matter · Physics

Heating Curve of Water Simulation: Latent Heat

Heat a block of ice on a burner in 3D and watch it warm, melt, warm again, boil and turn to steam while the temperature–heat graph draws itself. See why the temperature stops rising during melting and boiling, read the specific heats of ice, water and steam from the slopes, and drop ice into warm water to find whether it all melts.

Interactive virtual lab · no download · works on phones and laptops

Chapter: Thermal Properties of Matter
For: Class 9–11 · JEE · NEET
Time: ~25 min

Heating Curve of Water is a Pro simulation

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How to use it

1Pick a module from the list (4); press play to heat.
2Drag the orange knob on the burner to set its power, or use the sliders for mass and temperatures.
3Use Predict before you look, then Derive, Questions, Practise and Compare.

What to notice

Temperature stays at 0 °C while ice melts and at 100 °C while water boils: the heat goes into changing state.
Boiling takes far longer than melting: L_v ≈ 6.7 L_f for water.
Steeper slope, smaller heat capacity: ice and steam warm about twice as fast as water.
In a mixture, check first whether there is enough heat to melt all the ice.

For teachers

A ready-made teaching kit comes with this lab

Lesson plan
27 min, 4 steps
Ask the class
4 questions with answers
Quick quiz
5 questions, printable
Key formulas
4 formulas

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About the Heating Curve of Water simulation

The heating curve of water is the graph of temperature against heat supplied as ice is turned into steam, and reading it is a core skill from Class 9 Matter to Class 11 Thermal Properties of Matter and NEET. In this heating curve simulation a block of ice sits in a beaker on a burner in 3D, with a thermometer in it. Press play: the ice warms, melts at 0 °C, the water warms and boils at 100 °C, and the steam heats — while the graph draws itself, coloured by stage.

The two flat parts are where the heat goes into changing state instead of raising the temperature — the latent heats of fusion (336 kJ/kg) and vaporisation (2260 kJ/kg). Turn on the particles to see why, and compare how long melting and boiling take on the same burner. The slopes of the sloping parts give the specific heats: ice and steam warm about twice as fast as water. Put a second beaker with more ice on an identical burner and race them.

The last module is the calorimetry question JEE and NEET ask: drop ice into warm water and find the final temperature — after first checking whether the water has enough heat to melt all the ice.

Also covers: heating curve of water, heating curve, ice to steam, temperature vs heat graph, latent heat of fusion, latent heat of vaporisation, melting point, boiling point, phase change, change of state, specific heat of ice, specific heat of water, specific heat of steam, slope of heating curve, why temperature stays constant while boiling, calorimetry, ice and water mixture, mixing ice in water, final temperature of mixture, class 9 matter, class 11 thermal properties.

Frequently asked questions

Why does temperature stay constant while ice melts or water boils?

During a change of state the heat supplied goes into breaking or loosening the attractions between molecules — raising their potential energy — not into making them move faster. Temperature measures the average kinetic energy, so it stays the same until the change of state is complete. The heat absorbed is the latent heat.

Why is the boiling part of the heating curve so much longer than the melting part?

Water's latent heat of vaporisation (2260 kJ/kg) is about 6.7 times its latent heat of fusion (336 kJ/kg). Boiling separates the molecules completely and pushes back the atmosphere as the vapour expands; melting only loosens them.

How much heat converts 1 kg of ice at −20 °C into steam at 100 °C?

Warm the ice: 1 × 2100 × 20 = 42 kJ. Melt it: 336 kJ. Warm the water: 1 × 4200 × 100 = 420 kJ. Boil it: 2260 kJ. Total 3058 kJ, of which boiling alone is about three-quarters.

What do the slopes of a heating curve tell you?

With a steady heater, the slope of temperature against heat is 1/(mc). The steeper the slope, the smaller the specific heat: ice and steam (about 2000–2100 J/kg·K) rise about twice as steeply as liquid water (4200 J/kg·K).

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