PAUSED · Water heating

Heating & Cooling Curves

Matter, energy and phase changes

Workspace

Experiment

Mission: add energy and identify why temperature pauses at melting and boiling.

Energy controls

Heater power700 W

Sample mass250 g

Simulation speed1×

Camera zoom1.00×

Interaction sounds

Live measurements

Temperature−20.0 °C

Energy moved0 kJ

StateSolid

Time0.0 min

The sample is ice. Added energy first increases molecular vibration and temperature.

Object focus

Tap the sample, heater, thermometer, particles, or a curve point.

Temperature–time trace

Temperature Energy

Teacher tools

Reveal deeper explanation

Interactive lecture

Language

Voice source

Voice

Ready. The lecture will not start automatically.

Step 1 of 100%

1. Reading heating and cooling curves

What to watch: The sample, thermometer and curve respond together.

A heating curve follows temperature while energy enters matter. Watch the beaker, the thermometer, and the trace move together.

Chapters

Learning objectives

Read slopes and plateaus on heating and cooling curves.
Connect temperature to average particle kinetic energy.
Explain latent heat using changing intermolecular arrangement.
Predict effects of mass, power, substance, and pressure.

Key concepts

Sloped regions: one phase warms or cools. Temperature changes according to energy moved, mass, and specific heat capacity.

Flat regions: two phases coexist. Energy rearranges particles, so temperature stays near the phase-change point.

Model: transferred energy = mass × specific heat capacity × temperature change within one phase. During a change of phase, transferred energy = mass × latent heat.

Values are educational approximations at the chosen pressure; particle spacing and time are visually scaled.

Try these experiments

Maximize heater power. Does the boiling temperature change, or only the time to reach it?
Double the mass. Compare the slope of the temperature trace.
Choose high-altitude boiling and inspect the liquid surface.
Cool steam and count the reversed phase changes.

Applications & questions

Food preparation at altitude, refrigeration, steam power, freeze protection, and material processing all depend on these energy plateaus.

Why can steam cause a severe burn at the same temperature as boiling water?
Where does energy go while ice melts?
Why does insulation change the rate but not the equilibrium phase-change temperature?

Common misconceptions

Boiling is not simply “getting hotter.” At steady pressure, liquid at its boiling point can absorb much more energy while its temperature barely changes. Particles do not stop moving on a plateau; their arrangement changes.

Curve challenge

0 / 7