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If you supply the exact same 1,000 joules of electrical energy to a 1 kg block of aluminum and a 1 kg block of lead, the lead heats up nearly seven times hotter. Different materials store thermal energy differently, and measuring that difference accurately in a lab is one of the most tested skills in physics.
The specific heat capacity (cc) is the amount of energy needed to raise the temperature of 1Β kg1\text{ kg} of a substance by 1∘C1^\circ\text{C} (or 1Β K1\text{ K}). We calculate it using Ξ”E=mcΔθ\Delta E = m c \Delta \theta, where Ξ”E\Delta E is thermal energy in joules (J\text{J}), mm is mass in kilograms (kg\text{kg}), and Δθ\Delta \theta is temperature change in degrees Celsius (∘C^\circ\text{C}).
How do we wire an experiment to measure each of these variables without letting energy escape undetected?

The Required Apparatus

A standard setup uses a 1Β kg1\text{ kg} metal cylinder with two drilled boreholes: one for an immersion heater and one for a temperature probe or thermometer. We measure electrical energy input directly using a digital joulemeter, or calculate it from a voltmeter, ammeter, and stopwatch using E=VItE = V I t.
Air is a poor thermal conductor, so adding a few drops of oil or water into the thermometer borehole eliminates insulating air gaps and ensures good thermal contact. Wrapping the block in thick foam and resting it on an insulating mat prevents thermal energy from escaping into the bench and air.
Taking a single start and end reading can hide heating delays, so how do we extract the most reliable value of cc from continuous data?

Graphical Analysis

By recording temperature every 60Β s60\text{ s} as energy increases, we can plot a graph of temperature (ΞΈ\theta) on the y-axis against work done (EE) on the x-axis. Rearranging Δθ=1mcΞ”E\Delta \theta = \frac{1}{m c} \Delta E shows that the linear portion of this graph has a gradient of 1mc\frac{1}{m c}.
Even with insulation, what happens when the block gets significantly hotter than room temperature?