Thermal Properties of Matter – Meaning, Effects, and Formulas

What are Thermal Properties of Matter?
Thermal properties describe how matter behaves when heat is added or removed.
In simple words – It’s how solids, liquids, and gases react to heating or cooling.

1️⃣ Temperature and Heat

• Temperature: A measure of how hot or cold something is.
• Heat: A form of energy that flows from a hotter body to a colder one.

2️⃣ Thermal Expansion

When a substance is heated, its particles move faster and the substance expands.

• Linear Expansion (solids): ΔL=L0αΔT\Delta L = L_0 \alpha \Delta TΔL=L0​αΔT
• Area Expansion: ΔA=A0βΔT\Delta A = A_0 \beta \Delta TΔA=A0​βΔT
• Volume Expansion: ΔV=V0γΔT\Delta V = V_0 \gamma \Delta TΔV=V0​γΔT

Where α,β,γ\alpha, \beta, \gammaα,β,γ are expansion coefficients.

3️⃣ Specific Heat Capacity (c)

The amount of heat required to raise the temperature of 1 kg of a substance by 1°C.

Q=mcΔTQ = m c \Delta TQ=mcΔT

Where:

• QQQ = heat supplied
• mmm = mass
• ccc = specific heat
• ΔT\Delta TΔT = change in temperature

4️⃣ Change of State (Latent Heat)

Heat can change a substance from solid → liquid → gas without changing temperature.

• Latent Heat of Fusion (LfL_fLf​) – Heat required to change solid to liquid.
• Latent Heat of Vaporization (LvL_vLv​) – Heat required to change liquid to gas.

Formula:

Q=mLQ = m LQ=mL

5️⃣ Modes of Heat Transfer

1. Conduction: Heat transfer through solids (spoon in hot tea).
2. Convection: Heat transfer through fluids by movement (boiling water).
3. Radiation: Heat transfer without a medium (Sun’s heat reaching Earth).

Daily Life Examples:

• Railway tracks expanding in summer.
• Ice melting at 0°C.
• Boiling water in a pot.

Summary:

Thermal properties explain how matter reacts to heat. Heat changes temperature, size, and state of matter, and is transferred through conduction, convection, and radiation.