Physics 4 — Thermo & Fluids

Heat & specific heat

continues from lesson 1 — values defined earlier in the course stay live here

Heat is energy in transit: Q = m·c·ΔT. Water's c is enormous (4186 J/kg·K) — which is why oceans tame climates and why boiling a liter takes real time:

m_{w} := 1 kg

= 1 kg one liter of water

c_{w} := 4186 J/(kg*K)

= 4186 J / (kg K) specific heat of water

dT := 80 K

= 80 K from 20 °C to boiling

Q_{boil} = m_{w} \cdot c_{w} \cdot dT

= 334880 J ~335 kJ

t_{kettle} := Q_{boil} / (2000 W)

= 167.44 s a 2 kW kettle needs ~167 s — check yours!