The amount of thermal energy Δ*Q* transferred through an area *A* per unit time Δ*t* is called the heat flux.
In the case of conduction, the heat flux is governed by the following relationship:

ΔQ/Δt=-kAΔT/Δx

where Δ*T* is the temperature difference along a distance Δ*x* in the direction of conduction
and *k* is the thermal conductivity of the material. This is known as **Fourier's Law of Heat Conduction**.

Properties of some materials:

Material | Conductivity (W/m·°C) | Specific heat (J/kg·°C) | Density (kg/m^{3}) |
---|---|---|---|

Water (20°C) | 0.58 | 4181 | 1000 |

Air (20°C) | 0.024 | 1012 | 1.024 |

Copper | 401 | 385 | 8940 |

Foam | 0.08 | 1300 | 30-120 |

The following simulations examine how each of these factors affects the rate of heat conduction. Click an image to open the corresponding simulation.