Lab 10 Thermodynamics PHY250L
Student Name: Click here to enter text.
Access Code (located on the underside of the lid of your lab kit): Click here to enter text.
Lab Report Format Expectations
Utilize college level grammar and formatting when answering text based questions.
Report all equations in a proper mathematical format, with the correct signs and symbols.
Submissions with incomplete or improperly formatted responses may be rejected.
Pre-Lab Questions
1. The first law of thermodynamics discusses the interplay between heat and work and how they
come together to describe the internal energy changes of a system undergoing a
thermodynamic process. Importantly, though, the first law of thermodynamics is, at its core, a
statement about the conservation of energy. Energy cannot be created or destroyed. it cannot
vanish into nothingness or spontaneously appear. This law can be stated mathematically as:
𝛥𝑈 = 𝑈 − 𝑈
Explain how this equation demonstrates both the first law of thermodynamics and the concept of conservation of energy.
Click here to enter text.
2. Note the negative (-) sign for work, W, in the above equation. The choice of a negative or a
positive sign depends on the way you describe the system.
Explain when the work term would have a positive magnitude and when it would have a
negative magnitude. In your response, utilize the work equation, which is below, to justify your
response.
𝑈 = −𝑈𝑈𝑈𝑈 𝑈 𝑈𝑈
Click here to enter text.
, Lab 10 Thermodynamics PHY250L
3. The second law of thermodynamics states that the entropy of an isolated system can never
decrease over time, and is constant if and only if all processes are reversible. Isolated systems
spontaneously evolve towards thermodynamic equilibrium—the state of maximum entropy of
the system. More simply put: the entropy of the universe (the ultimate isolated system) only
increases and never decreases.
Explain, using probability theory and the concepts of macrostates and microstates, why entropy
increases. Be specific and state your response with enough detail that your level of
understanding is clearly demonstrated.
Click here to enter text.
4. When you put a few drops of food coloring in water, the molecules of food coloring will
eventually diffuse throughout the whole glass. Use the Second Law of Thermodynamics to
explain why the entropy of the diffused food coloring is greater than when you initially drop the
food coloring into the water. Your response should tie in the same concepts of microstates,
macrostates and entropy that you described in your response to Question 4, above.
Click here to enter text.
Student Name: Click here to enter text.
Access Code (located on the underside of the lid of your lab kit): Click here to enter text.
Lab Report Format Expectations
Utilize college level grammar and formatting when answering text based questions.
Report all equations in a proper mathematical format, with the correct signs and symbols.
Submissions with incomplete or improperly formatted responses may be rejected.
Pre-Lab Questions
1. The first law of thermodynamics discusses the interplay between heat and work and how they
come together to describe the internal energy changes of a system undergoing a
thermodynamic process. Importantly, though, the first law of thermodynamics is, at its core, a
statement about the conservation of energy. Energy cannot be created or destroyed. it cannot
vanish into nothingness or spontaneously appear. This law can be stated mathematically as:
𝛥𝑈 = 𝑈 − 𝑈
Explain how this equation demonstrates both the first law of thermodynamics and the concept of conservation of energy.
Click here to enter text.
2. Note the negative (-) sign for work, W, in the above equation. The choice of a negative or a
positive sign depends on the way you describe the system.
Explain when the work term would have a positive magnitude and when it would have a
negative magnitude. In your response, utilize the work equation, which is below, to justify your
response.
𝑈 = −𝑈𝑈𝑈𝑈 𝑈 𝑈𝑈
Click here to enter text.
, Lab 10 Thermodynamics PHY250L
3. The second law of thermodynamics states that the entropy of an isolated system can never
decrease over time, and is constant if and only if all processes are reversible. Isolated systems
spontaneously evolve towards thermodynamic equilibrium—the state of maximum entropy of
the system. More simply put: the entropy of the universe (the ultimate isolated system) only
increases and never decreases.
Explain, using probability theory and the concepts of macrostates and microstates, why entropy
increases. Be specific and state your response with enough detail that your level of
understanding is clearly demonstrated.
Click here to enter text.
4. When you put a few drops of food coloring in water, the molecules of food coloring will
eventually diffuse throughout the whole glass. Use the Second Law of Thermodynamics to
explain why the entropy of the diffused food coloring is greater than when you initially drop the
food coloring into the water. Your response should tie in the same concepts of microstates,
macrostates and entropy that you described in your response to Question 4, above.
Click here to enter text.
