What is the difference between temperature and thermal energy?

Temperature is a measure of how hot or cold an object is and decides which way thermal energy flows; thermal energy always flows from a region of higher temperature to one of lower temperature. Thermal (internal) energy is the total energy of the particles in an object. A bath of warm water has a lower temperature than a spark but holds far more thermal energy because it has many more particles.

What is specific heat capacity?

Specific heat capacity is the energy needed to raise the temperature of one kilogram of a substance by one degree Celsius (or one kelvin). The energy is found from $E = m c \Delta\theta$, where $m$ is mass, $c$ is the specific heat capacity, and $\Delta\theta$ is the temperature change. Water has a high specific heat capacity, so it heats up and cools down slowly.

Why does temperature stay constant while ice melts?

During melting, the energy supplied (the latent heat of fusion) is used to break the bonds holding the particles in the solid arrangement, not to raise the temperature. So the thermometer stays at the melting point until all the ice has melted. The same happens during boiling, where the temperature stays at the boiling point while the liquid turns to gas.

How do conduction, convection and radiation differ?

Conduction is the transfer of thermal energy through a solid by particle vibration, with no overall movement of the material, and is best in metals. Convection is the transfer through liquids and gases by the movement of the heated fluid, which rises as it becomes less dense. Radiation is the transfer by infrared waves and needs no medium, which is how heat from the Sun reaches Earth through empty space.

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Thermal Physics for Singapore N(A)-Level Science (Physics) 5105/5106: temperature and how a liquid-in-glass thermometer works, specific heat capacity and latent heat in changes of state, and the transfer of thermal energy by conduction, convection and radiation

A Singapore N(A)-Level Science (Physics) overview of Thermal Physics (SEAB 5105/5106). It covers temperature and how a liquid-in-glass thermometer works, specific heat capacity and the latent heat involved in melting and boiling, and the three ways thermal energy transfers: conduction, convection and radiation.

Generated by Claude Opus 4.85 min readSEAB-5105Updated 2026-06-13

Reviewed by: AI editorial process; not yet individually human-reviewed

Jump to a section

What this module covers
Temperature and thermometers
Heat capacity and changes of state
Transfer of thermal energy
How this module is examined
Check your knowledge

What this module covers

Thermal Physics explains heat and temperature in N(A)-Level Science (Physics) 5105/5106. It starts with what temperature really measures and how a thermometer turns it into a reading, then looks at how much energy is needed to warm a substance or change its state, and finishes with the three ways thermal energy moves from place to place.

These ideas explain everyday things, from why a metal spoon feels cold to why a kettle boils dry at a fixed temperature, and they connect to the energy module. Each dot point below has full worked answers and practice questions.

Temperature and thermometers

Temperature and thermometers explains temperature as a measure of how hot or cold an object is, and that thermal energy always flows from higher to lower temperature until both are equal. A liquid-in-glass thermometer works because the liquid expands when warmed and rises up a narrow tube, giving a reading against a fixed scale.

Heat capacity and changes of state

Heat capacity and changes of state uses the specific heat capacity to find the energy needed to change the temperature of a substance:

E = m c \Delta\theta.

During a change of state, melting or boiling, the temperature stays constant while the latent heat is supplied to break the bonds between particles.

Transfer of thermal energy

Transfer of thermal energy describes the three ways heat moves. Conduction passes energy through solids by particle vibration and is best in metals. Convection carries energy through liquids and gases as the heated fluid becomes less dense and rises, setting up a convection current. Radiation transfers energy by infrared waves and needs no medium, so it can cross empty space, as with sunlight.

How this module is examined

Use the right formula. For warming, $E = m c \Delta\theta$ ; during melting or boiling, the temperature stays constant.
Name the mechanism. Match conduction to solids, convection to fluids, and radiation to infrared across a vacuum.
State the direction. Thermal energy flows from hot to cold until temperatures are equal.

Check your knowledge

Recall and calculation questions across the module. Attempt them, then check the worked solutions.

State the difference between temperature and thermal energy. (2 marks)
State the direction in which thermal energy flows between two objects at different temperatures. (1 mark)
Calculate the energy needed to heat $0.50\ \text{kg}$ of water by $30\ \degree\text{C}$ . Take $c = 4200\ \text{J kg}^{-1}\,\degree\text{C}^{-1}$ . (2 marks)
Explain why the temperature stays constant while ice is melting. (2 marks)
Name the method of heat transfer that does not need a medium. (1 mark)

Sources & how we know this

Singapore-Cambridge GCE N(A)-Level Science (Physics, Chemistry) Syllabus 5105/5106 — Singapore Examinations and Assessment Board (2026)