1. Defining Phases of Matter

2. SolidsGasesLiquids http://itl.chem.ufl.edu/2045_s99/lectures/lec_f.html http://www.scienceteacherprogram.org/chemistry/JClar k05.html Micro Macro

3. SolidsGasesLiquids - has its own shape - don’t really flow -particles barely moving, low energy - takes the shape of its container -flow -particles moving, medium energy - takes the shape of its container -flow -particles moving fast, high energy

4. What is heat? How much motion do the molecules have?

5. Let’s Talk about Gases Gases have a tremendous capacity to expand or contract with change in temperature

6. What happened to the size of our balloons as the temperature got colder? 1. Why? (Write this down) 2. Liquid nitrogen is – 196 degrees C 3. The balloons shrank a lot! 4. Is there a temperature that the balloons would have shrunk to nothing? Write down what you think.

7. THE KELVIN SCALE OF TEMPERATURE in the nineteenth century, Lord Kelvin, an Englishman, invented an new temperature scale suitable for measuring low temperatures When a material is cooled, it looses heat, and its temperature decreases, until a point is reached where it has no more heat left to loose At this point it is not possible to lower the temperature any further This low temperature is called absolute zero

8. How Cold Can Things Get? Absolute Zero 0 degrees K (Kelvin) -273.15 degrees (Celsius) At temperatures near 0 K, nearly all molecular motion ceases If there is no motion, then there is essentially no volume Lowest Natural Temperature Ever Recorded on Earth, −89.2 °C Lowest Man-Caused Temperature - MIT scientists have cooled a sodium gas to the lowest temperature ever recorded -- only half-a-billionth of a degree above absolute zero The laws of thermodynamics state that absolute zero cannot be reached

9. The Kelvin Scale is useful for solving gas law problems

10. Temperature Degrees Celsius Degrees Kelvin Degrees Fahrenheit °C °K °F Boiling point of water100373212 Average human body temperature37310.198.6 Melting point of ice027332 Liquid nitrogen-19677-325 Absolute 0-273 070 Common temperature comparisons:

11. Hot air balloons were extremely popular in France in the 1800s French scientist Jacques Charles made measurements on how the volume of a gas was affected by the temperature of the gas. Why Do Hot Air Balloons Fly?

12. Charles’s Law The volume of a gas varies directly with the temperature in degrees Kelvin Volume = Constant x Temperature Example 1. Volume = 1 cm3 at 1 degree Kelvin What is the volume if we raise the temperature to 2 degrees K?

13. The Change in Volume is Proportional to: Ending temperature (°K) divided by starting temperature (°K)