Temperature Depends on Particle Movement

By — Maya Brantner

All matter is made of moving particles

You may know that any object in motion has kinetic energy. Even objects so small you cannot even see have kinetic energy. When you look at a chair it doesn't seem to be moving, but yet it also has kinetic energy. This is because all of the atoms and particles inside are always moving. All matter is made of atoms, which are always in motion. The motion of atoms gives an object its energy.

The Kinetic Theory of Matter

Physical properties and changes are a result of how particles of matter behave. The kinetic theory of matter states that all of the particles that make up matter are always in motion which means all particles have kinetic energy. This helps explain different states of matter. The three different states of matter are solid, liquid and gas.  Watch the linked video below to see how particles in a solid, liquid and gas would act.

After you watch the video, you should know how the particles move and act in their different ways. The particles don't always move at the same speed. Some move faster than others and may collide into each other. When faster particles collide with others, they may lose speed but when slower ones are hit by faster particles, they gain speed. Particles will often change speeds.

Tempertaure and Kinetic Energy

Kinetic energy depends on speed, but it is not possible to know the amount of kinetic energy an object holds. Perhaps, the average kinetic energy of particles can be determined. Temperature is a measure of the average kinetic energy of all the particles in an object. The hotter the temperature, the more kinetic energy or speed the particles take in. The colder an object is, the lower the temperature and the lower the average kinetic energy it has. You experience temperature and kinetic energy every day. Kinetic energy depends on not only speed but mass as well. Particles in solids do not move as fast as particles in a gas, however, the particles in  solids have more mass. In that case, the solids could have as much kinetic energy as the gas and they could have equal temperatures.

Thermometers

A thermometer is what you use to measure tempertaure. A thermometer is what measures temperature through the regular variation of some physical property of the material inside the thermometer. The inside of the thermometer always expands or contracts by a certain amount in response to a change in temperature. As the temperature increases, liquid filled thermometers measure how much the liquid expands in a narrow tube. There are lines on the thermometer that are marked so you can read the degrees. Degrees are units which are equally spaced between two points. Thermometers used to be filled with mercury, but now it is too dangerous so they are filled with alchohol instead. Some thermometers use a material whose electrical properties change when the temperature changes.

Citation - http://www.dreamstime.com/royalty-free-stock-photos-set-thermometers-image19039148

Thermal Expansion

Thermal expansion is the property that makes liquid filled thermometers work.  This affects many substances, such as gases, liquids, solids, alcohol, liquid mercury, etc. One job that often uses thermal expansion is a construction  engineer. The Gateway Arch in St. Louis was built by them and is an interesting example.  The expansion happened when the sun would hit the narrow gap between the legs and prevent the last piece of the bridge from going into place. Engineers had to fix it by spraying water on the side where the sun hit. Thermal expansion happens in many different objects, which can be good and bad.