Chapter 6, Section 7 Laws of Thermodynamics: Too Hot, Too Cold, Just Right HW: 6.7 PTG, pg. 676, #1-9 LO: LO: Explain Explain the the 3 3 Laws Laws of of Thermodynamics Thermodynamics as as they they relate relate to to conservation
conservation of of energy energy SC: SC: Assess Assess experimentally experimentally the the final final temperature temperature when when two two liquids liquids of of different different temperatures
temperatures are are mixed mixed Assess Assess experimentally experimentally the the final final temperature temperature when when aa hot hot metal metal is is added added to to cold cold water water
Calculate Calculate the the heat heat lost lost and and heat heat gained gained of of two two objects objects after after they they are are placed placed in in thermal contact
thermal contact Discover Discover if if energy energy is is conserved conserved when when two two objects objects are are placed placed in in thermal thermal contact contact and and reach reach equilibrium
equilibrium temperature temperature Explain Explain the the concept concept of of entropy entropy as as it it relate relate to to objects objects placed placed in in thermal thermal contact.
contact. Do Now: Write LO and SC on new left side page WDYS/WDYT: pg 664 Agenda: Do Now Investigate Summary Investigate #1-3 #1-complete in your notebook #2-3 Create a data table in your notebook to record all data. #3 b-c Construct graph and use to answer questions
Investigate #4-5 Plan experiment, check procedures with teacher. Conduct experiment Investigate #6 Read Physics Talk, Specific Heat, pg 666-67 Complete #6 a-c Summary Discuss how this experiment proves the law of conservation of energy. HW: 6.7 PTG, pg. 676, #1-9 LO: LO: Explain Explain the
the 3 3 Laws Laws of of Thermodynamics Thermodynamics as as they they relate relate to to conservation conservation of of energy energy SC: SC: Assess Assess experimentally experimentally the
the final final temperature temperature when when two two liquids liquids of of different different temperatures temperatures are are mixed mixed Assess Assess experimentally experimentally the the final final temperature
temperature when when aa hot hot metal metal is is added added to to cold cold water water Calculate Calculate the the heat heat lost lost and and heat heat gained gained of
of two two objects objects after after they they are are placed placed in in thermal contact thermal contact Discover Discover if if energy energy is is conserved conserved when when two
two objects objects are are placed placed in in thermal thermal contact contact and and reach reach equilibrium equilibrium temperature temperature Explain Explain the the concept concept of of entropy entropy as
as it it relate relate to to objects objects placed placed in in thermal thermal contact. contact. Do Now: What does Conservation of Energy mean to you? Explain your answer Agenda:
Do Now Physics Talk Practice Problems Summary Physics Talk What did you observe in your experiment? Equal amounts of hot and cold water produced a final temp half way between the initial temps of both When you changed the amounts of hot or cold water the final temp was somewhere between the two initial
temps, but closer to the temp of the water with the larger mass. Physics Talk What is the Law of Conservation of Energy? The total energy in a system is conserved, energy can neither be created or destroyed Start=End The cold water gained thermal energy through the transfer of heat, then the hot water must have lost
and equal amount of thermal energy. Physics Talk What equation can we use to show the Law of Conservation of Energy? Mass of water? 1mL=1g 50mL=50g Physics Talk What is specific heat? Energy is
conserved whether the cool water is mixed with hot water or hot metal. The heat energy (J) required to raise the temp of mass (1g) for a substance by 1C. Physics Talk What is the equation for specific heat? Physics Talk Sample Problem Physics Talk
Conservation of EnergyAgain! Energy is not created or destroyed! It can change from one from to another, but the total amount remains the same in a closed system! Example: From GPEKE Physics Talk What is the difference between Temperature, Heat,
and Thermal Energy? Temperature is the measure of average kinetic energy of molecules. High Temp--> more KE Physics Talk What is the difference between Temperature, Heat, and Thermal Energy? Heat is the energy transferred from one place to
another due to temperature differences. Transfers from High heat to low heat Physics Talk What is the difference between Temperature, Heat, and Thermal Energy? Thermal energy is a type of energy that results from the motion of atoms (related to temperature) Increase thermal energy,
increase temperature Depends on the mass and temperature of the water 100g of hot water > 100g of cold water water because because of of the difference in temp A swimming pool with 10,000kg cold water > 1kg hot water due to mass Physics Talk What is thermodynamics? The study of the relationships
between heat and other forms of energy transformation of one form into another. There are 3 laws of thermodynamics. Physics Talk Zeroth Law of Thermodynamics If 2 objects have the same temperature as a third object, then the two objects must also have the
same temperature. If A=C, and B=C, then A=B Physics Talk First Law of Thermo Dynamics Conservation of energy related to hot and cold objects. Hot Coffee (90C) + Cold Milk (5C) Coffee cools (10C) slightly, Milk warms a lot (75C)until they are at the same temperature (80C) Could be calculated with the equation if you know
the mass of the coffee and milk. Physics Talk Second Law of Thermodynamics In irreversible processes, entropy or disorder always increases. Time is irreversible Thermal energy is transferred from hot objects to cold objects and NEVER goes from cold to hot spontaneously.
Physics Talk Second Law of Thermodynamics Energy is only transferred from hot objects to cold objects until they reach an equilibrium temperature. There is NO SUCH THING AS COLD ENERGY! Physics Talk Second Law of Thermodynamics (cont)
Due to Entropy. Related to the degree of disorder of molecules. Solids are more organized (ordered) than liquids which are more ordered than liquids. To go from solidliquidgas the object must gain thermal energy, increasing entropy. Physics Talk Example of Entropy
Checking Up Questions Pg. 672, #1-4 Vocabulary Boxes Complete for all vocab words in Chapter 6, Section 7. Essential Questions Pg. 675 What does it mean? How do you know? Why should you care? Physics To Go 6.7 PTG, pg. 676, #1-9
