A TEMPERATURE DIFFERENCE. A TRANSFER OF ENERGY.
Thermal conduction.
Hold the ends at different temperatures. Explore the gradient, inspect the particles and measure the heat flow.
Inside the conductor
Temperature / °C050100150200
Drag with either mouse button to pan. Scroll or pinch to zoom. Click the conductor to move the probe. The view never rotates. Vibration-amplitude differences are exaggerated to make hotter and colder regions easier to compare.
The temperature profile
Steady stateWhat changes the heat-transfer rate?
Here k is thermal conductivity, A is cross-sectional area and L is conductor length. ΔT = Tright − Tleft. Positive heat flow is towards the right.
A steeper gradient, a greater rate
A larger end-temperature difference increases the rate. A longer conductor reduces it. Increasing the cross-sectional area or thermal conductivity increases the rate. Energy flows from the hotter end towards the colder end.
Vibrating particles, stationary solid
Particles oscillate around fixed positions; they do not travel down the conductor. Hotter regions have greater average vibrational energy. In metals, mobile electrons also transfer energy; they are not drawn here.
About this model
One-dimensional, uniform conduction with insulated sides, ideal contact with fixed-temperature reservoirs and constant thermal conductivity. Changes apply the new steady state immediately; this is not a simulation of the warm-up process. The same rate crosses every section.
The particle picture is schematic: a regular array is used for every material, including glass, rather than its actual atomic structure. Vibrations are enlarged and slowed. Hotter regions have larger displayed amplitudes; their contrast is exaggerated for visibility and does not represent the actual amplitude ratio. Particles still vibrate at 0 °C. Particle count, spacing and conductor thickness are not to scale. These illustrative motions do not calculate the heat-transfer rate.
Preset conductivities are representative constant values, not precision data over the full temperature range. Reference: OpenStax: Conduction.
Explore thermal conduction in a solid
Change material, conductor length, cross-sectional area and both end temperatures. Inspect the steady-state temperature profile and heat-transfer rate, then zoom and pan through a schematic view of particles vibrating around fixed positions.
Practise thermal conduction and energy-transfer concepts for IB Physics, A Level and AP Physics. The end reservoirs remain at fixed temperatures and the sides are insulated. The particle motion is enlarged and slowed, with exaggerated amplitude contrast for clarity; it does not calculate the conduction rate.