Key relationship
Before/after freezing: dT/dt=−P/(mc); plateau time=mLf/P.
Physics · Practical apparatus
Wax freezing plateau
Follow cooling through a state change. Heat continues leaving during freezing while temperature remains near the model freezing point, because latent heat is released.
Open the interactive experiment →Wax freezing plateau
உறையும் போது வெப்பம் வெளியேறினாலும் வெப்பநிலை மாறாது. மறைவெப்பம் வெளியிடப்படுவதால் நிலைத்த வெப்பப் பகுதி உருவாகிறது.
Key notes, relationships and model limits
Practical tip
Follow cooling through a state change. Heat continues leaving during freezing while temperature remains near the model freezing point, because latent heat is released.
Common trap
A freezing plateau records latent-heat removal. This ideal single-component guide does not reproduce the freezing range of every wax mixture.
Model limits
ideal single-component wax surrogate with one freezing temperature and constant controlled heat removal. Real wax mixtures may freeze over a range; liquid and solid heat capacities are taken equal.
What you will learn
Adjust wax freezing plateau apparatus, observe its reading and derive the indicated physical quantity.
Try the experiment
Try both scenarios, change one control, and predict the result before checking the graph and readouts.
Think of it this way
Change one input while keeping the others fixed, as you would in a controlled experiment.
Worked example
For 50 g wax with Lf=180 kJ/kg at 20 W removal, plateau duration is 450 s.
Why this matters
The model connects wax freezing plateau with an observable reading. Check the equation and assumptions before applying it.
Before you start
SI units · algebra · graph reading
Check your understanding
During the freezing plateau, removed energy mainly changes?
- The temperature with no change of phase fraction.
- The liquid fraction, rather than temperature.
- The total mass of the wax.
Read the explanation
The liquid fraction, rather than temperature.
Course connection: Virtual apparatus preparation. Check exact board/exam membership in the syllabus sources. Physical practical work remains necessary.