Glossary
Change in temperature (ΔT)
The difference between the final and initial temperatures of a substance, indicating how much its thermal state has altered. It is measured in degrees Celsius (°C).
Example:
If a cold drink warms up from 5°C to 20°C, its change in temperature is 15°C.
Conduction
The transfer of thermal energy through direct contact between particles, without any bulk movement of the material itself. It is the primary mode of heat transfer in solids.
Example:
When you place your hand on a cold metal railing, heat is transferred from your hand to the railing via conduction.
Cross-sectional area (A)
The area of a two-dimensional slice taken perpendicular to the direction of heat flow through a material. A larger area allows for more heat transfer.
Example:
A wider window pane will allow a greater cross-sectional area for heat to escape a house compared to a narrow one.
Heat energy transferred (Q)
The amount of thermal energy that moves from one object or system to another due to a temperature difference. It is measured in Joules (J).
Example:
When you touch a hot stove, the heat energy transferred from the stove to your hand causes a burn.
Insulators
Materials that have low thermal conductivity, meaning they resist the flow of heat and slow down heat transfer.
Example:
The foam in a coffee cup acts as an insulator to keep your drink hot by preventing rapid heat loss.
Intrinsic Property
A characteristic of a material that depends only on its composition and structure, not on its size, shape, or amount. Specific heat and thermal conductivity are examples.
Example:
The density of gold is an intrinsic property of the element itself, regardless of whether it's a small nugget or a large bar.
Mass (m)
A measure of the amount of matter in an object, typically measured in kilograms (kg) in physics. It directly influences the total heat energy required for a temperature change.
Example:
A larger mass of water will require more heat energy to boil compared to a smaller mass.
Metals
A class of materials generally characterized by high thermal conductivity and low specific heat, allowing them to transfer heat quickly and change temperature rapidly.
Example:
Cooking pans are often made of metals like copper or aluminum because they efficiently transfer heat from the stove to the food.
Rate of heat transfer (Q/Δt)
The amount of heat energy transferred per unit of time, representing how quickly thermal energy moves through a material. It is measured in Watts (W) or Joules per second (J/s).
Example:
A well-insulated cooler minimizes the rate of heat transfer from the outside to keep drinks cold for longer.
Specific heat
The amount of energy required to raise the temperature of 1 kg of a substance by 1°C. It indicates a material's resistance to temperature change.
Example:
A large swimming pool takes much longer to heat up under the sun than a small puddle because water has a very high specific heat.
Thermal conductivity (k)
A material property that quantifies its ability to conduct heat, indicating how quickly heat energy can flow through it.
Example:
A metal spoon quickly gets hot when stirring soup due to the high thermal conductivity of the metal.
Thickness of the material (L)
The distance heat must travel through a material, measured in meters (m). A greater thickness generally reduces the rate of heat transfer.
Example:
A thick winter coat provides better insulation than a thin jacket because its greater thickness of the material slows down heat loss.
Water
A common substance known for its exceptionally high specific heat, meaning it requires a large amount of energy to change its temperature.
Example:
Coastal regions experience milder temperature swings than inland areas because the large bodies of water nearby absorb and release heat slowly.