PHYSICS
NAME OF LEARNER:
Thermodynamics
SECTION:
Topic:
1st Law of Thermodynamics
Content Standards
The learners demonstrate understanding of 1st law of
thermodynamics.
Performance Standards
The learners should be able to solve, using experimental
and theoretical approaches, multi-concept, rich-content
problems.
DATE:
Learning Competencies (MELCS)
State the relationship between changes internal energy,
work done, and thermal energy supplied through the
First Law of Thermodynamics. (STEM_GP12GLTIIh-62)
Learning Outcomes
SCORE:
distinguish the relationship among internal energy, work
done, and thermal energy (heat) using the 1st Law of
Thermodynamics;
perform a virtual laboratory activity using a simulation to
justify the statements of the 1st Law of Thermodynamics.
Prepared by:
JONATHAN B. JULITO
MA in Phyics Education
Introduction
THERMODYNAMICS
Thermodynamics is the study of the relations between heat, work, temperature,
and energy. The laws of thermodynamics describe how the energy in a system
changes and whether the system can perform useful work on its surroundings.
Heat and Internal Energy
Internal Energy is all the energy of a system that is
associated with its microscopic components - atoms and
molecules. This energy includes the following - random
rotational and vibrational motion of molecules, potential
energy within and between molecules.
Heat is the transfer of energy across the boundary of a
system due to a temperature difference between the
system and its surroundings.
In our study, we will mostly consider the interaction of
energy of a system with its surrounding. The diagram on
the right shows the difference of a system from
surroundings and how it is found inside one universe.
The system, like the flask and the cylinder, holds energy.
This energy may transfer from the system to the
surroundings through heat. This happens when the
system has a higher temperature compared to the
surroundings.
Heat may also move from the
surroundings to the system
when it has higher temperature
compared to the system.
Warm it up!
Instructions: You have learned all about the methods of heat transfer. Lets us have a quick recall of
these concepts! Study the diagram below and identify whether convection, radiation or
conduction process is present.
Introduction
When heat is transferred, there will changes in the temperature. Like in the
figure above, the blue block will have increase in temperature upon the
transfer of energy from the red block.
This change in temperature would commonly indicate a change in the
internal energy.
However, there are also instances wherein energy is transferred by heat
without changing the temperature. This occurs through compression or
expansion of materials such as gas. This transfer of energy is achieved
through work.
WORK
It is the measure of energy transfer that occurs when an object is moved over a
distance by an external force at least part of which is applied in the direction of the
displacement.
Work done
Work done on a system - the measure of energy
transferred from the surroundings to the
system
Work done by the system - the measure of
energy transferred from the system to the
surroundings
Remember that energy comes in different forms
and one of which is the mechanical energy. This
energy is composed of the kinetic and potential
energy which is produced due to the motion and
configuration of the system.
Application of concept
What enables the hot air balloons to fly? Write a
brief explanation below.
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Explore
The First Law of Thermodynamics states that energy can be
converted from one form to another with the interaction of
heat, work and internal energy, but it cannot be created nor
destroyed, under any circumstances.
Mathematically, this is represented as:
ΔU=q+w
Virtual Laboratory Activity: Energy, Heat and Work
Objectives:
At the end of this activity, you will be able to:
use a PHET simulation on the 1st Law of Thermodynamics;
distinguish the relationship between heat, work and internal energy of a system
using PHT simulation;
Materials:
PHET simulation (access via application or online)
pen and paper
PHET Simulation:
Explore
Virtual Laboratory Activity: Energy, Heat and Work
Procedure:
Part A
1. Ready a clean piece of paper and a ballpen.
2. Open the PHET simulation on the 1st Law of Thermodynamics.
3. Study how you will use the PHET simulation. Use the guide below.
4. This little guy
represents
the
"work" involved in
the simulation. If
you
push
the
handle
to
the
right,
the
surroundings
is
doing work on the
system,
If
the
little
guy
is
pushed back, the
system of gas is
doing work on the
surroundings.
5. Thermometer indicates
increase
or
decrease
temperature in the system.
the
in
2. Click on the handle of the
pump and pull up to introduce
gas in the container.
6. Gauge measures the pressure
in the container.
1. Press Measurement Tools to
activate the ruler for the
container.
3. Move the blue arrow up to
add heat and down to remove
heat.
Notice
that
the
simulation will show fire and
ice, respectively.
Part B
1. Pump gas into the container until the initial temperature reaches 300K.
2. Observe the measurement of the pressure when the gas was introduced.
a. Guide Question 1: Did the pressure increase or decrease? Explain.
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3. Add heat on the system.
a. Guide Question 2: What happened to the pressure in the container?
b. Guide Question 3: What happened to the temperature in the container?
Explain.
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c. Guide Question 4: What happened to the volume of the gas? Is the work done
by the system or on the system? Explain.
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4. Remove heat from the system. (Move blue arrow down).
a. Guide Question 5: What happened to the pressure in the container?
b. Guide Question 6: What happened to the temperature in the container?
Explain.
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c. Guide Question 7: What happened to the volume of the gas? Explain.
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Explore
Virtual Laboratory Activity: Energy, Heat and Work
Procedure:
5. Move the yellow handle to the right.
h. Guide Question 8: What happened to the pressure in the container. Explain.
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i. Guide Question 9: What happened to the temperature in the container? Explain.
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j. Guide Question 10: Is work being done on the system or done by the gas
system? Explain.
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Conclusion:
Based on the activity, how are heat, work and internal energy related with each
other?
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3. Move the blue arrow up to
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add heat and down to remove
heat.
Notice
that
the
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simulation
will show fire and
ice, respectively.
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References
1st Law of Thermodynamics. (2013, October 2). Retrieved October 22, 2021, from
Chemistry LibreTexts website:
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Text
book_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Thermo
dynamics/The_Four_Laws_of_Thermodynamics/First_Law_of_Thermodynamics
‌‪G as Properties‬. (2021). Retrieved October 22, 2021, from Colorado.edu website:
https://phet.colorado.edu/sims/html/gas-properties/latest/gas-properties_en.html
‌R ichardson, M. (2012). First law of Thermodynamics with PHET [YouTube Video].
Retrieved from https://www.youtube.com/watch?v=DlyBaIy6Zj4