Specific heat capacity tells you how much energy a substance soaks up per degree of temperature rise. This reference lists Cp, in joules per kilogram-kelvin, for more than fifty solids, liquids, and gases near room temperature, searchable by name and filterable by phase.
How it works
Specific heat capacity at constant pressure, Cp, links heat to temperature
through Q = m · Cp · ΔT. Here Q is the heat added in joules, m the mass in
kilograms, and ΔT the temperature change in kelvin (the same size as a degree
Celsius). Rearranging, Cp = Q / (m · ΔT), so the units are J/(kg·K). A high Cp
means a substance needs a lot of energy to warm up and gives a lot back as it
cools — it has high thermal mass.
Why values differ so widely
Lightweight molecules with many ways to store energy have high Cp. Hydrogen gas tops the table at about 14,300 J/kg·K because its tiny molecules pack many modes of motion per kilogram. Water is unusually high for a liquid at about 4,186 J/kg·K because its hydrogen-bond network absorbs energy before raising kinetic temperature. Dense metals like gold and lead sit near the bottom, around 130 J/kg·K, since each kilogram contains relatively few, heavy atoms that each carry limited thermal energy.
Selected values at a glance
| Substance | Phase | Cp (J/kg·K) | Practical note |
|---|---|---|---|
| Water | Liquid | ~4,186 | Climate moderator, excellent coolant |
| Aluminium | Solid | ~900 | High Cp for a metal; good for cookware |
| Copper | Solid | ~385 | Low Cp; heats and cools quickly |
| Iron / steel | Solid | ~450–490 | Moderate thermal mass |
| Concrete | Solid | ~880 | High thermal mass in buildings |
| Air (dry) | Gas | ~1,005 | Reference for HVAC calculations |
| Ethanol | Liquid | ~2,440 | Lower than water; less thermal buffering |
| Glass | Solid | ~840 | Similar to concrete |
Values are approximate near 25°C and atmospheric pressure. Real values vary by alloy composition, humidity, and temperature.
Worked examples
Hot-water cylinder. Heating 150 kg of water from 15°C to 60°C: Q = 150 × 4186 × 45 ≈ 28.3 MJ ≈ 7.85 kWh. That single calculation explains why domestic water heating accounts for a substantial share of household energy — water’s high Cp means large amounts of energy are needed and stored.
Radiator comparison. The same 28.3 MJ applied to 150 kg of cast iron (Cp ≈ 460 J/kg·K) would raise its temperature by 28.3×10⁶ / (150 × 460) ≈ 410°C — illustrating why iron radiators hold heat after a boiler shuts off but cannot store nearly as much total energy per kilogram as water.
Concrete floor heating. A 200 mm thick concrete floor slab with density ~2,300 kg/m³ has significant thermal mass. Heating 1 m² of floor from 18°C to 22°C: (0.2 × 2300) × 880 × 4 ≈ 1.62 MJ. Architects use this calculation to assess whether a slab can buffer overnight heat charging for passive solar designs.
Cp versus Cv: when it matters
For solids and liquids, Cp and Cv are nearly identical because these phases barely expand when heated. For gases, Cp is noticeably larger than Cv because heating at constant pressure allows the gas to expand and do work on its surroundings — that extra energy is included in Cp. Air has Cp ≈ 1,005 J/kg·K but Cv ≈ 718 J/kg·K. For most engineering calculations involving gas in open systems (fans, ducts, compressors), Cp is the appropriate value.
Temperature dependence
The values in this table are representative near 25°C. Over wide temperature ranges Cp shifts — water’s Cp changes modestly between 0°C and 100°C, while gases and polymers show larger variation. Near phase transitions (melting, boiling) the apparent Cp spikes as latent heat is absorbed. For precise engineering work over large temperature ranges, use enthalpy tables or polynomial fits rather than a single Cp value.