For a fixed material, heat is directly proportional to both mass and temperature change. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

Start from the base case

The base case needs 30 joules of heat.

Qbase=30 JQ_{\text{base}} = 30\ \text{J}
Heat contrastComparable bars share one energy scale.30 Jbase60 Jmore mass60 Jmore warming

Double the mass

Keeping the material and warming the same, doubling mass doubles the heat to 60 joules.

Qmore mass=230 J=60 JQ_{\text{more mass}} = 2\cdot 30\ \text{J} = 60\ \text{J}

Double the temperature change

Keeping the mass and material the same, doubling the temperature change also gives 60 joules.

Qmore warming=230 J=60 JQ_{\text{more warming}} = 2\cdot 30\ \text{J} = 60\ \text{J}
Heat contrastComparable bars share one energy scale.30 Jbase60 Jmore mass60 Jmore warming

Either doubled factor doubles the heat

The bars show three comparable cases on one scale. Mass and temperature change are separate factors, but each is direct.

casechanged factorQbasenone30 Jmore massm60 Jmore warmingΔT60 J\begin{array}{c|c|c}\text{case}&\text{changed factor}&Q\\\text{base}&\text{none}&30\ \text{J}\\\text{more mass}&m&60\ \text{J}\\\text{more warming}&\Delta T&60\ \text{J}\end{array}
Heat contrastComparable bars share one energy scale.30 Jbase60 Jmore mass60 Jmore warming