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Specific heat capacity of a solid (or water) sim

Heat a 1.00 kg block or water with a 12 V immersion heater, read the thermometer each minute, fit a line to your graph and work out c, bare or lagged, by joulemeter or by V, I and a stopwatch.

Thermal properties: specific heat capacity · covers the O-Level, IGCSE, GCSE topic

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What the sim shows

A 12 V, 50 W immersion heater sits in one hole of a 1.00 kg block (or in 0.500 kg of stirred water) and a thermometer in the other, with a drop of oil for good thermal contact. Time moves only when you act: Switch on logs the 0 s reading, and each press of Read thermometer is 1 minute of the experiment, then one reading to 0.5 °C. Switch off after 10 minutes and take 2 more readings: the temperature still creeps up (thermal lag), because the heater is hotter than the block. Energy supplied E = joulemeter reading, or E = VIt. Fit the best-fit line through the straight middle part only; then c = P ÷ (m × gradient), or c = E ÷ (m Δθ). Data book: aluminium 900, copper 385, iron 450, brass 380, water 4200 J/kg °C (Kaye & Laby, Tables of Physical and Chemical Constants, 16th ed. (1995), §2.3.6, rounded for school use). Heat lost to the room makes the measured c too high: the bare aluminium block loses about 0.26 W for every °C above 20 °C (the smaller blocks about 0.12 W/°C), and lagging cuts this to a fifth; some energy also warms the heater (about 40 J/°C), the thermometer and, for water, the beaker. The graph's temperature axis is set from the sample and heater (20 °C + P t ÷ (m c) for 10 minutes, plus 10 % headroom); 75 W is offered only for aluminium and water, so no reading can pass the thermometer's 110 °C. Model: heater and sample as two lumps joined by a 2.5 W/°C link, Newton's-law losses to a room at 20 °C, a thermometer that lags by 5 s, a heater of constant 2.88 Ω, and seeded reading scatter of about ±0.2 °C; heat spreading inside the block is not followed in detail.

  • Thermometer: read to 0.5 °C, one reading per press
  • Block or beaker of water, heater, joulemeter (or voltmeter and ammeter), supply, stopwatch, foam lagging jacket
  • Red leads: the positive side of the circuit; black leads return to the supply

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