150 likes | 165 Views
Temperature. Ms. Messina’s Science Class. Temperature. A measure of the thermal energy in an object A measurement of the average kinetic energy of the particles in a sample (how fast molecules are vibrating) The three temperature scales are Celsius, Kelvin, and Fahrenheit.
E N D
Temperature Ms. Messina’s Science Class
Temperature • A measure of the thermal energy in an object • A measurement of the average kinetic energy of the particles in a sample (how fast molecules are vibrating) • The three temperature scales are Celsius, Kelvin, and Fahrenheit
What temperature really is • 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.
Thermometer • An instrument used for measuring temperature
How a thermometer works • The volume of alcohol in a thermometer contains huge numbers of alcohol molecules. • As temperature increases, the alcohol molecules move faster and bounce off each other. • The liquid alcohol expands and takes up more space in the thermometer.
Celsius • Most commonly used by scientists throughout the world • Water freezes at 0 degrees and boils at 100 degrees on the Celsius Scale
Kelvin • This is the metric unit (SI) of temperature • 0 degree K is coldest possible temperature (-273 degree Celsius) Absolute Zero • Kelvin uses the same scale as Celsius • Water freezes @ 273 degree and boils at 373 degrees Kelvin
Fahrenheit • Used in the United States • Water freezes at 32 degree and boils at 212 degrees Fahrenheit • Different Scale than C and K
Important Concepts • As temperature rises the molecules in an object begin to move faster • As temperature decreases, the molecules move slower
Temperature and Density • As molecules move faster (temp. rises), they take up more space (volume increases) • As volume increases density decreases • So the opposite I true, as temperature decreases the volume decreases and density increases
Converting to Kelvin • The Kelvintemperature scale is useful in science because it starts at absolute zero. • To convert from Celsius to Kelvin, you add 273 to the temperature in Celsius.
Absolute zero • Absolute zero is -273°C. • You cannot have a temperature lower than absolute zero. • Think of absolute zero as the temperature at which atoms are “frozen.”
What temperature really is • Temperature measures the kinetic energy per molecule due to random motion.