If matter is heated and also thus that is temperature rises much more and more, it can be watched that the particles consisted of in the move ever before faster – be it the relatively totally free movement the the particles in gases or the oscillation around a rest position in solids.

You are watching: What is the relationship between temperature and particle motion

Animation: affect of temperature on bit motion and thermal expansion

The temperature that a substance can thus be concerned as a measure of the velocity the the particles it contains. With a higher temperature and thus higher particle velocity, the kinetic energy of the particles also increases. Because of this the adhering to statement uses :

The greater the temperature the a substance, the higher the kinetic energy of the particles!

Animation: affect of temperature on particle motion and also thermal expansion

More details on the connection between temperature and also particle motion, especially for gases, can be uncovered in the post “Kinetic concept of gases“.

Note the particle activity in the paper definition of temperature is constantly a random motion! The temperature that the cube presented in the animation above would not rise if the were relocated at high speed and also the individual corpuscle were claimed to be faster. This is because it is no much longer a random motion of the separation, personal, instance particles. Rather, the random motion of the particles is superimposed by a directed motion of the cube. Such directed motions have actually no affect on the random activity of the particles inside the material and thus on the temperature.

Temperature is a measure of the “not directed” kinetic power of a fragment in a substance!

Thermal expansion

As the temperature rises, the higher the bit velocity and also the greater the an are occupied by the particles. As a result, building material generally broaden as the temperature rises. Whereas this way that a substance typically contracts once cooled. The result decrease in volume is connected with boost in thickness (see additionally the animations in the previous section).

Figure: influence of temperature on bit motion and thermal expansion

The phenomenon that substances generally expand when boil is also known together thermal expansion. This result is used, for example, in liquid-in-glass thermometers to measure temperatures.

As the temperature rises, the volume the substances normally increases as result of the increased space occupied through the particles!

Note that temperature is eventually a macroscopic quantity (i.e. It can be measure up macroscopically), while fragment velocity have the right to only be observed on a microscopic scale. Nevertheless, both amounts are connected! For additional information watch the write-up “Maxwell-Boltzmann distribution.


The adhering to table summarizes the properties of the corpuscle in the various states of matter.

state of mattersolidliquidgas
particle velocitylowmediumhigh
kinetic energyof the particleslowmediumhigh
occupiedvolume *lowmediumhigh
binding energyof the particleshighmediumlow(ideal: none)

*) Note: with some building material such as e.g. Water, a so-called negative heat expansion (NTE) wake up in a certain temperature range, which leads to rise in volume in spite of falling temperature. Read more about this in the post Density anomaly of water.

Brownian motion & diffusion

Since each substance have the right to be assigned a specific temperature, the molecules contained in it space obviously in continuous motion. This (random) thermal activity of the particles as result of the temperature is additionally called Brownian motion. Brownian motion have the right to be observed indirectly if an open ink glass is closely placed in a water.

Figure: Glass of squid in water to show Brownian fragment motionAnimation: Glass of squid in water to demonstrate Brownian particle motion

Even if the water and also the ink space macroscopically completely at rest, one will notice after some time a mixing of the water through the ink. The factor for this is the Brownian movement of the particles which reasons the water molecules (shown in red) and also ink molecules (shown in blue) come mix due to permanent collisions. Distinctions in concentration room gradually balanced out. Together mixing of different substances is additionally called diffusion.

Figure: Illustration of Brownian particle movement with ballsAnimation: Illustration that Brownian particle activity with balls

Diffusion refers to the mix of substances due to Brownian movement (striving because that diffusion equilibrium)!

The greater the temperature, the quicker the diffusion will certainly be, since the stronger the molecule movement and thus the “mixing”.

See more: Do They Have Fourth Of July In England, What Brits Really Think Of Independence Day

In a similar means as the mix of different gases or liquids deserve to be attributed to Brownian motion, a motion of corpuscle can likewise be observed in solids. Return the corpuscle in solids space usually bound come a specific location by the electrostatic attraction forces, lock oscillate more or much less strongly about their rest position, relying on the temperature. As result of these oscillations of the corpuscle (shown in red), foreign particles (shown in blue) deserve to move v the atomic structure. The particles are “pushed” with the atom structure, so to speak.

Figure: Diffusion in solidsAnimation: Diffusion in solids

As the temperature increases, the lattice oscillations increase and also the distances in between the oscillating particles increase too. This enables diffusing corpuscle to move much better through the lattice structure. Again applies: the greater the temperature, the quicker the diffusion processes!

Diffusion is a temperature managed process, i.e. The higher the temperature, the much faster the diffusion!