What is Temperature?
Liya C.

Definition of Temperature
Temperature is basically the measure of the molecules in an object or the measure of heat and coolness. In scientific terms, temperature is the measure of the average kinetic energy of something’s molecules and the kinetic energy shows how fast the molecules move. It is also the property of systems that determines the direction of energy flow as heat. Temperature is also associated with the sense of hot and cold.

Measurement of Temperature
Thermal energy can be measured with a thermometer and is the amount of energy a substance has because the molecules are moving. Heat energy is a measure of the total of the energy of the molecules. There are three temperature scales in use today: the Fahrenheit temperature scale which is used in the U.S.A. and some other English speaking countries, the Celsius scale which is standard in almost all the countries, and the Kelvin scale, which is recognized as the standard for scientific measurement.

Figure 1

In early times people used water or water-alcohol mixtures as the liquid inside thermometers. Water was not a good choice because when it is below room temperature it contracts but when it nears freezing point it expands. In 1714 the German physicist Daniel Gabriel Fahrenheit made a better choice by choosing mercury as the liquid. Mercury has a uniform volume that changes with temperature, a lower freezing point and a higher boiling point than water plus it does not wet the glass.

Heat and Temperature
Heat, temperature, and thermal energy can all have to do with the microscopic movement in matter and the movements are explained by what is called the kinetic theory of matter. Heat is a form of energy that flows from hot objects to cold objects because of their difference in temperature. The cool object absorbs the energy and becomes warmer. Usually the effect of the energy transferring from the warm object to the cool one is a rise in temperature for the cooler object and a decrease in temperature for the warmer object. Heat travels in three ways: by conduction, convection, or radiation. The important difference between heat and temperature is that heat is a form of energy in something and temperature is the measure of that energy. At the molecular level, temperature is related to the random movements of the molecules and atoms in matter. Because there are different kinds of motion, the particles can take different forms and each form contributes to the total kinetic energy of the particles.

Examples of Temperature
Microwaving a bowl of soup raises the temperature of the soup by speeding up the molecules. A burning match is at a much higher temperature than an iceberg but an iceberg contains much more energy than a burning match. In warmer water the molecules move faster than they move in colder water. If two objects of different temperatures are brought together, heat/energy flows from the warmer object to the cooler object.

Example of how temperature can change

Kinetic Energy- The energy possessed by a system or object as a result of its motion.
Conduction -The transfer of heat between objects that are in direct contact with each other.
Convection - The up and down movement of gases and liquids caused by heat transfer.
Radiation -When electromagnet waves travel through space it is called radiation, and when the waves come into contact with an object, they transfer heat to the object.
Electromagnet waves - Waves of energy associated with electric and magnetic fields.
Molecules -A group of two or more atoms held together by chemical bonds.

Editors of Time-Life books, Physical Forces, Alexandria, VA Time-Life, 1992, print.
"heat." Compton's by Britannica. Encyclopædia Britannica Online School Edition.Encyclopædia Britannica, Inc., 2012. Web. 13 Sept. 2012.<http://school.eb.com/all/comptons/article-307224>.

Jerry Coffey, What is Temperature, September 16, 2012

McGrath, Kimberly A, the Gale Encyclopedia of Science Book Six, Detroit: Gale Group 2001, Print
"temperature." Encyclopædia Britannica. Encyclopædia Britannica Online School Edition.Encyclopædia Britannica, Inc., 2012. Web. 13 Sept. 2012.<http://school.eb.com/eb/article-9071632>.

temperature. ( 2012). In Encyclopædia Britannica. Retrieved from http://school.eb.com/eb/article-9071632
Encyclopædia Britannica Online School Edition, s.v. "temperature," accessed September 13, 2012, http://school.eb.com/eb/article-9071632.

temperature 2012. Encyclopædia Britannica Online School Edition. Retrieved 13 September 2012, from http://school.eb.com/eb/article-9071632