Thermal Expansion of Solids - Vocabulary Flashcards

Vocabulary flashcards covering key concepts from the lecture notes on thermal expansion of solids.

Thermal expansion

The tendency of matter to increase in size when the temperature increases.

Thermal contraction

The tendency of matter to decrease in size as the temperature decreases.

Linear thermal expansion

The increase in a solid’s length due to a rise in temperature, described by ΔL = α ΔT L0 for small ΔT.

Change in length (ΔL)

The difference between a final length and the original length: ΔL = L − L0.

Change in temperature (ΔT)

The difference between the final and initial temperatures: ΔT = T − T0.

Original length (L0)

The length of an object at the reference temperature T0.

Coefficient of linear expansion (α)

A material-specific constant relating ΔL to ΔT; has units of 1/°C (or K−1).

Volume expansion

The change in an object's volume due to a temperature change; described by the volume expansion equation for solids and liquids (gases use the ideal gas law).

Gases and ideal gas law

For gases, thermal expansion is typically described by the ideal gas law rather than solid/liquid expansion equations.

Expansion joint

An assembly designed to absorb expansion and contraction in structures to prevent damage.

Buckling

Deformation or instability in a structural component due to thermal expansion if not accommodated.

Thermal stress

Stress that develops when a restrained object changes temperature, potentially causing cracks or deformation.

Piston and cylinder expansion

In engines, the thermal expansion of pistons and cylinders must be accounted for to maintain performance and avoid failure.

Bearings and shafts expansion considerations

Choice of bearings/shafts must account for thermal expansion to prevent binding or failure.

Rail gaps

Gaps between rails to accommodate expansion and prevent buckling.

Wood joinery

Traditional carpentry methods that accommodate movement due to wood expansion/contraction without damage.

Steel tower expansion example

Example: steel tower height changes with temperature; ΔL = α ΔT L0, with steel α ≈ 1.2×10−5 K−1.

α units

The coefficient of linear expansion α has units of 1/°C (or K−1) and is scale-independent (°C or K give the same numerical value).

Holes and thermal expansion

Holes in an object expand along with the object during thermal expansion.

PCB expansion effects

Thermal expansion of components in printed circuit boards can affect electrical integrity and cause warping if not managed.