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The chaotic movement of colloidal particles, which was first observed by the Scottish botanist Robert Brown (1773–1858), is called Brownian motion.

Brownian motion is caused by collisions of the molecules of the dispersion medium with the small, dispersed colloidal particles.

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This is a simulation of Brownian motion (named for Robert Brown, but explained in some detail by Albert Einstein). Brownian motion is the apparently random motion of something like a dust particle in the air, driven by collisions with air molecules. The simulation allows you to show or hide the molecules, and it tracks the path of the particle. See if you think there is any dependence on temperature - you can control the temperature with the slider.

Simulation first posted on 8-9-2018. Written by Andrew Duffy

This work by Andrew Duffy is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
This simulation can be found in the collection at http://physics.bu.edu/~duffy/classroom.html.
The counter has been running on this page since 8-9-2018. The number of people accessing the page since then is:

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This is a simulation of Brownian motion (named for Robert Brown, but explained in some detail by Albert Einstein). Brownian motion is the apparently random motion of something like a dust particle in the air, driven by collisions with air molecules. The simulation allows you to show or hide the molecules, and it tracks the path of the particle.

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Iodine is an example of a substance that undergoes sublimation.

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Iodine is an example of a substance that undergoes sublimation.

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When can sublimation occur?

Sublimation occurs in solids with vapor pressures that exceed atmospheric pressure at or near room temperature.

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In general, ionic solids have high melting points because relatively strong forces hold them together.

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In general, ionic solids have high melting points because relatively strong forces hold them together.

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Why solids do not flow, even though their particles are constantly moving?
In a solid, the particles are packed tightly together and vibrate around fixed points. Even though the particles vibrate, they are limited in their movement and cannot flow.

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How are the structure and properties of solids related?
The general properties of solids reflect the orderly arrangement of their particles and the fixed locations of their particles.

The melting point (mp) is the temperature at which a solid changes into a liquid.

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Under what conditions does boiling occur?

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Under what conditions does boiling occur?

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When a liquid is heated to a temperature at which particles throughout the liquid have enough kinetic energy to vaporize, the liquid begins to boil.

The boiling point (bp) is the temperature at which the vapor pressure of the liquid is just equal to the external pressure on the liquid.

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Why heating a liquid causes evaporation to occur faster?

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Why heating a liquid causes evaporation to occur faster?

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Evaporation occurs when particles have enough kinetic energy to overcome the forces holding the particles together in a liquid. Heating a liquid increases the average kinetic energy of its particles. Increasing the average kinetic energy increases the number of particles with enough energy to escape the liquid by evaporating.

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What is the relationship between evaporation and kinetic energy?

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What is the relationship between evaporation and kinetic energy?

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During evaporation, only those molecules with a certain minimum kinetic energy can escape from the surface of the liquid.

Even some of the particles that do escape collide with molecules in the air and rebound back into the liquid.

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What factors determine the physical properties of a liquid?

The interplay between the disruptive motions of particles in a liquid and the attractions among the particles determines the physical properties of liquids.

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What is the relationship between the temperature in kelvins and the average kinetic energy of particles?

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What is the relationship between the temperature in kelvins and the average kinetic energy of particles?

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The Kelvin temperature of a substance is directly proportional to the average kinetic energy of the particles of the substance.

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How does kinetic theory explain gas pressure?

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How does kinetic theory explain gas pressure?

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Gas pressure is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object.

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The kinetic theory as it applies to gases includes the following fundamental assumptions about gases.

1. The particles in a gas are considered to be small, hard spheres with an insignificant volume.

2. The motion of particles in a gas is rapid, constant, and random.

3. The motion of particles in a gas is rapid, constant, and random.

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A substance changes state when there is a change in the balance between the random motion of its particles and the attractions among those particles.

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At still higher pressures and lower temperatures, the particles become fixed in orderly arrangements, producing solids.

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At higher pressures and lower temperatures, the particles slow down and exert attractive forces on one another, producing a liquid.

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The state of a substance is determined by conditions of pressure and temperature.

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Low pressures and high temperatures favor gases, in which particles move randomly in constant, high-speed motion.

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The word kinetic refers to motion.
This theory explains the states of matter, based on the concept that all matter consists of tiny particles that are in constant motion.

The energy an object has because of its motion is called kinetic energy.

According to the kinetic theory, all matter consists of tiny particles that are in constant motion.

The particles in a gas are usually molecules or atoms.