1. Ms. Messina’s Science Class
Temperature
Ms. Messina’s Science Class

2. 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

3. 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.

4. Thermometer
An instrument used for measuring temperature

5. 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.

6. Celsius Most commonly used by scientists throughout the world
Water freezes at 0 degrees and boils at 100 degrees on the Celsius Scale

7. 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 273 degree and boils at 373 degrees Kelvin

8. Fahrenheit Used in the United States
Water freezes at 32 degree and boils at 212 degrees Fahrenheit
Different Scale than C and K

9. Important Concepts
As temperature rises the molecules in an object begin to move faster
As temperature decreases, the molecules move slower

10. 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

12. Converting to Kelvin
The Kelvin temperature 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.

14. 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.”

15. What temperature really is
Temperature measures the kinetic energy per molecule due to random motion.