Direct answer: Specific heat capacity is not determined by whether a material is called a metal or a nonmetal. Near 298 K, selected values range from about 0.385 kJ/(kg·K) for solid copper to 4.185 kJ/(kg·K) for liquid water. The value depends on the particular substance, phase, and temperature.
This comparison uses reference values near 298 K (about 25 °C). It is a quick orientation for pure substances, not a design-property table for commercial alloys, composites, or materials over a broad temperature range.
Specific heat capacity near room temperature
| Substance | State at reference point | Specific heat capacity | Molar heat capacity | Source basis |
|---|---|---|---|---|
| Water | Liquid, 298 K | 4.185 kJ/(kg·K) | 75.38 J/(mol·K) | NIST Chemistry WebBook |
| Aluminum | Solid, 298 K | 0.897 kJ/(kg·K) | 24.20 J/(mol·K) | NIST Chemistry WebBook, JANAF |
| Graphite (carbon) | Solid, 298.15 K | 0.770 kJ/(kg·K) | 9.251 J/(mol·K) | NIST Chemistry WebBook; reported graphite measurement |
| Iron (alpha phase) | Solid, 298 K | 0.450 kJ/(kg·K) | 25.10 J/(mol·K) | NIST Chemistry WebBook, JANAF |
| Iron/steel (textbook reference) | Solid, near room temperature | 0.452 kJ/(kg·K) | Not applicable as one alloy molar mass | OpenStax teaching table; broad reference only |
| Copper | Solid, 298 K | 0.385 kJ/(kg·K) | 24.47 J/(mol·K) | NIST Chemistry WebBook, JANAF |
For readers looking specifically for steel, OpenStax lists iron/steel at 452 J/(kg·K) in a general physics teaching table. Treat that as an approximate classroom reference: “steel” includes many grades and conditions, so use data for the specified alloy when a calculation needs design accuracy.
The values show why “metals have low specific heat” is too broad. Aluminum’s mass-specific heat capacity is more than twice copper’s in this comparison. Liquid water is much higher than these solids, while graphite is a solid nonmetal whose value is in the same general range as several metals. All values describe particular phases and reference temperatures.
What the units mean
Mass-specific heat capacity, c, is the energy needed to raise one unit of mass by one degree. Its SI unit is J/(kg·K). Molar heat capacity uses amount of substance instead, in J/(mol·K). Convert a molar value to a mass-specific value by dividing by molar mass in kg/mol. For example, NIST lists liquid water at 298 K as 75.38 J/(mol·K); dividing by 0.0180153 kg/mol gives about 4,185 J/(kg·K).
For a temperature change without a phase change, and over a range where c can be treated as approximately constant, the heat estimate is q = m c ΔT. Here m is mass and ΔT is final minus initial temperature. If the heat capacity changes appreciably with temperature, use temperature-dependent data and integrate rather than assuming one constant value. This page compares material values; see our specific heat capacity formula guide for a worked calculation, and heat-capacity reference notes for additional context.
Specific heat is not thermal conductivity
Specific heat describes how much energy per unit mass corresponds to a temperature change. Thermal conductivity describes how readily heat moves through a material under a temperature gradient. They answer different questions. A high specific heat does not, by itself, make a material a good heat sink or insulator; density, geometry, conductivity, boundary conditions, and the required operating temperature also matter. For engineering selection, use data for the actual grade, phase, and temperature range.
How to use these values responsibly
- Check whether a source reports specific or molar heat capacity and verify the units before comparing values.
- Match the phase: liquid water and ice are different states with different heat capacities; iron can also change phase with temperature.
- Treat pure-element values as reference points, not substitutes for a named alloy, filled polymer, or manufactured material specification.
- Use temperature-dependent measurements or a validated property database when the calculation spans a wide temperature range or affects a safety-critical design.
References
- NIST Chemistry WebBook: Water, liquid-phase heat capacity (298 K: 75.38 J/(mol·K)).
- NIST Chemistry WebBook: Aluminum, solid-phase heat capacity (298 K: 24.20 J/(mol·K)).
- NIST Chemistry WebBook: Copper, solid-phase heat capacity (298 K: 24.47 J/(mol·K)).
- NIST Chemistry WebBook: Iron, solid-phase heat capacity (298 K: 6.00 cal/(mol·K), alpha-delta phase range).
- NIST Chemistry WebBook: Carbon, graphite solid heat-capacity data (9.251 J/(mol·K) at 298.15 K in the cited measurement).
- OpenStax Physics: Heat, Specific Heat, and Heat Transfer (definitions, units, and the constant-property heat equation).
Reference data are approximate values for named phases near 298 K. Confirm the material, phase, temperature range, and source uncertainty before using them in design.
