1. Laws and Specific Heat
February 18, 2014

2. Objectives
1. State the three law of thermodynamics
2. Describe how Specific Heat capacity
affects our earth’s climate
3. Understand Thermal Expansion in terms
of how ice and water react

3. Laws of Thermodynamics
1. First law states:
a. When heat flows in or out of a system it is
being neither created or destroyed
b. It only transfers to a different place

4. Laws of
Thermodynamics
2. Second Law states:
a. Heat flows from a hot to a cold substance
b. Has to be forced to move the opposite
direction

5. Laws of
Thermodynamics
3. Third Law states:
a. No system can reach
zero
absolute
What is absolute zero?
How do we know where it is at if we can’t reach
it?

6. HEAT
1. Heat is thermal energy in motion
2. Heat is measured = Joules/ Calories

7. Specific Heat Capacity
3. Different substance = different capacities
for storing thermal energy
a. Require different amounts of thermal energy
to raise temperature

8. Specific Heat Capacity
4. Specific Heat Capacity: quantity of heat
required to change the temperature of a
unit mass by 1 degree
a. Measure of thermal inertia
b. Matters ability to resist a
in temperature
change

9. Higher specific heat – stronger ability to
resist change
Lower specific heat – low ability to resist
change

10. Specific Heat Capacity
5. Which has a higher specific heat
capacity, water or sand? In other words
which takes longer to warm in sunlight (or
longer to cool at night?)

11. Specific Heat Capacity
6. Waters specific heat capacity:
a. Higher capacity for storing energy
b. Absorbs a great quantity of heat for small
rises in temperature
c. Takes much longer to cool, resistant to
loosing thermal energy

12. Specific Heat Capacity
d. Water’s specific heat changes the
world’s climate
i. Currents carry warmer water to Europe’s
west coast keeping it warmer than the
cool coast’s of Canada
ii. Islands and peninsula’s do not
have extreme temperatures

14. 7. Bermuda is close to North Carolina, but
unlike North Carolina, it has a tropical
climate year round. Why?

15. Thermal Expansion
February 20, 2014

16. Thermal Expansion
1. Thermal expansion - when a substance
expands when heated and contracts
when cooled
a. Different substances have different abilities
to expand and contract

17. Bimetallic strips

18. Thermal expansion
b. When you can’t loosen a metal lid
on a glass jar, why is it that you
stick it under hot water to help you
out?

19. Thermal Expansion
2. Water’s Thermal expansion
a. Expands when heated
b. Between 0 and 4 degrees water particles
contracts becoming more dense before
freezing

20. Themal Expansion
a. If you heat water at zero degrees it actually
contracts as the ice crystals start to collapse
before it will expand at 4 degrees

21. Themal Expansion
3. When solid ice forms volume increases
because of the ice crystals

22. Thermal
Expansion
a. Since ice is less
dense it floats on bodies of water
b. Water at zero degrees is less dense
as well and stays near the tops
c. Water at four degrees is more
dense and will settle at the bottom keeping
organisms warm all winter