TeTempmpereratature ure (Sect. (Sect.

8.2)8.2) There are two There are two

common common temperature scales:temperature scales:

Fahrenheit scaleFahrenheit scale○ Water freezes at 32º

and boils at 212º

Celsius scaleCelsius scale○ Water freezes at 0º

and boils at 100º

Jennifer C. Brown

Jennifer C. Brown

TeTempmpereratature ure (Sect. (Sect.

8.2)8.2)

What is Temperature?What is Temperature?

Atoms are in constant motion, even in a solid object.

The back-and-forth jiggling of atoms is caused by thermal energy, which is a kind of kinetic energy.

Jennifer C. Brown

http://www.epa.gov/apti/bces/module1/kinetics/animation/kani1/kani104.htm

Jennifer C. Brown

TeTempmpereratature ure (Sect. (Sect.

8.2)8.2)

Temperature measures the kinetic energy per molecule due to random motion.

Average motion leads toa speed.

Random motionleads to a temp.

Jennifer C. Brown

A thermometer is an instrument that measures the exact temperature.

Most thermometers contain either a silvery fluid (mercury) or a red fluid, which is alcohol containing a small amount of red dye.

How do they work?

TeTempmpereratature ure (Sect. (Sect.

8.2)8.2)

Jennifer C. Brown

TeTempmpereratature ure (Sect. (Sect.

8.2)8.2) Absolute Zero? = Absolute Zero? = -273ºC = 0 K-273ºC = 0 K

Uses the Kelvin (K) ScaleUses the Kelvin (K) ScaleYou cannot have a temperature lower than

absolute zero.

Think of absolute zero as the temperature at which atoms are “frozen.”

Jennifer C. Brown

To convert from Celsius scale to Kelvin scale, you just add 273 to your Celsius temperature.