Physics 173, Physics of Sustainable Energy, Fall 2024

Lectures

The course meets on Tuesday and Thursday at 1pm - 2:20pm in Crow 204.

In-person attendence is not required but is strongly encouraged, since the material presented in lectures defines the course (there is no required textbook) and we use regular in-class exercises to reinforce learning. See the Grading section for information on in-class quizzes.

Personnel

Instructor:	Prof. Mark Alford Office: Compton 358;  Office hour: Monday, 4pm-5pm (Zoom links are on the course's Canvas page). Students are encouraged to ask questions via Piazza (see below) or to make appointments to see Prof. Alford in person or via zoom.
Assistant:	Macy Iyer Zoom help session: Monday 7:00-8:00pm (Zoom links are on the course's Canvas page) Students are also welcome to make appointments to see the assistant at other times.

Piazza

Piazza is a forum for students to ask questions, get answers, connect with other students, etc. You can participate anonymously if you want to. This course has its own Piazza page. You can also access Piazza via Canvas

Please enroll in the class Piazza forum.

iClicker

In this course, we will use iClicker for in-class quizzes and exercises.

1. If you do not already have the app, get it from iClicker.com
2. To use iClicker you will need a paid subscription. You may already have one if you are using iClicker in another course. You can decide whether to purchase iClicker for 6 months, a year, or longer.
3. If you do not already have an iClicker account, go to the iClicker website and create a student account. Find "Washington University in St. Louis" and then create the account. Be sure to use your @wustl.edu email address and WashU student ID number. When you're done, click "Sign In" to automatically link your account with Canvas.
4. Once you have an iClicker account, connect it to this course using code PMZP: go to join.iclicker.com/PMZP

Student support resources

Information on student resources, health and safety protocols, etc is available at the Provost's Syllabus Resources Page.

• Information on crisis support of students: Crisis Support Information
• Mental health services available at Habif Health and Wellness Center
• Mental health support available to students 24/7: Timely Care

Big questions:

• How will we generate and use energy in the future?
• How will we know which approaches are viable and which are not?

What we will cover:

Quantitative skills

• Be comfortable with numbers and simple arithmetic calculations
• Scientific notation (5×10⁶ = 5 million) and metric prefixes (kilo-, giga-, …)
• Units and conversion (kilograms to pounds, etc)
• Answering questions by making rough estimates, justifying them, and using them in simple calculations

Energy and Power

• Why is Energy so fundamental to everything?
• Tracking the flow of energy through a process
• Energy storage: why it matters; pros and cons of different ways of storing energy
• Cost and uses of different types of energy (coal, gasoline, natural gas, …)
• Difference between energy and power (power = rate of flow of energy)
• Typical power consumption/production of real world processes (power plant, car, a whole country, …)

Atoms and Heat

• Understand heat as movement of atoms
• Properties of atoms (size, mass, structure)
• The relationship between heat and temperature
• How we manipulate heat using heat engines and heat pumps; basic limitations on their performance

Climate change

• Climate history over the last million years
• Greenhouse effect, greenhouse gases
• A simple mathematical model of global heat balance
• Recent observations (measured temperature, extreme weather, size of polar ice caps) and their relation to climate change
• Role of fossil fuels in power generation and climate change.
• The Paris Agreement, Kyoto treaty, Cap and Trade
• Pros and cons of fossil fuels and alternative power sources (solar, nuclear, wind, biofuels, …)

Nuclei and Radioactivity

• Types of radioactivity
• The electromagnetic spectrum (X-rays, light, microwaves, …)
• Nuclear power and weapons: fission chain reaction
• Basic functioning of nuclear reactors. Properties of nuclear waste
• Health effects of radiation. Relation between dose (in Sieverts) and cancer risk

Required viewing (may be tested in quizzes and exams):

• Slides for lectures (previous and imminent)
• Course videos

Homework

Homework:

Current

All assigned so far

Instructions for writing a short report

Quizzes

All in-class quizzes

Midterm

Midterm exam

Course videos

These videos are part of the course, and students may be tested on their content.

	Unit conversions 1: basic technique
	Unit conversions 2: multiple units
	Are electric cars more eco-friendly?
	Heat and Temperature
	How do solar panels work?
	The importance of Energy Storage

Additional Videos

These videos are interesting additional material, most of which is part of the course, but some of which goes beyond what would be tested in quizzes or exams.

	Hydrogen versus Battery for electric vehicles
	Thermal equilibration: using heat to steal a PIN code using an iPhone
	How electricity is generated
	Explanation of air conditioner (i.e. heat pump)
	One form of Geoengineering: atmospheric aerosols
	Fracking explained
	A problem for solar power: the "duck curve"
	Animation of nuclear fission chain reaction (just ignore the mispronunciation of "nucleus"!)
	Short video describing nuclear fission
	A quick history and overview of nuclear power (with links to two more videos, pro and con)
	A quick explanation of nuclear fusion power

Optional extra material:

How to do well in this course

How I Rewired My Brain to Become Fluent in Math, an article on the importance of fluency, by Barbara Oakley

Useful reading

The book Physics and Technology for Future Presidents by Richard A. Muller, ISBN 978-0-691-13504-5, covers many of our course topics.

Extra practice problems

• Extra problems on scientific notation and energy, for students who need some additional practice on this.

Energy in our lives

• Explanation of hybrid cars (Union of Concerned Scientists)
• U.S. Energy Information Administration: lots of well-presented information about energy usage and production.
• How Does Your State Make Electricity? Interactive graphics from New York Times

Climate change

• How global warming works
• Intergovernmental Panel on Climate Change, 6th Assessment Report (2021-23)
• Controlling the global thermostat (Harvard Magazine, 2020)
• Cartoon showing global temperature through human history from xkcd
• The Milankovitch theory of the ice age cycle (NASA)
• Milankovitch and his cycles (Smithsonian)
• Carbon dioxide levels from 1700 to now (Scripps Institute).
• How ice cores can tell us about earth's climate in the remote past (NASA)
• NSF Ice Core Facility: how ice cores are obtained and studied

Greenhouse gas reduction

• Access current and projected per-capita GHG emissions from various countries
• McKinsey Analytics report on energy conservation. It dates from 2010, but is still an authoritative study.
• If everyone ate beans instead of beef: a different way to meet GHG targets

Nuclear energy

• YaleEnvironment article on "Why Nuclear Power Must Be Part of the Energy Solution"
• Physics Today article on Canada's plans for Small Modular Reactors
• Overview of thorium reactors
• Radiation dose chart from xkcd

Grading

Grades will be determined by a combination of homework, a midterm exam, in-class quizzes, and the final exam. The final grade will be a weighted average of homework (25%) midterm exam (35%) final exam + quizzes (40%) Contribution from Quizzes: If you do better on the final exam than on the quizzes, we ignore the quizzes, and use your final exam grade as 40% of your course grade. If you do better on the quizzes than on the final exam, we use 30% final exam plus 10% quizzes. So the quizzes can't lower your grade, but they can help compensate for a weak performance in the final exam. Your two lowest quiz grades will be dropped, to allow for occasional absences. PASS/FAIL: A grade of C+ or above counts as a "Pass".

Homework

• Purpose and Format:
  • Tests your understanding of material we have already covered
  • Contains multiple choice questions, along with regular questions or a short report
  • Must be submitted via Canvas by the due date and time.
  • Late homework will only be accepted by prior arrangement with the assistant or the professor
• Collaboration: Students are encouraged to form study groups and discuss the course material with each other, but each student must independently formulate his or her own homework solutions. Please make sure you understand the university's policy on academic integrity, especially the section on "Copying Or Collaborating On Assignments Without Permission".
• Partial Credit: When answering a question (other than multiple choice), you will usually only get partial credit if you just write down an answer, with no justification. To get full credit you need to give reasons why your answer is correct.
• Showing Units: When giving numerical answers, always show the units (eg 100 kg, 500 Calories, etc).

In-class Quizzes

• We will have one in-class quiz every week, on average.
• The quiz will end 10 minutes after the start of class, but students can (by prior arrangement with the professor) arrive early and start the quiz when they arrive, so there is no time limit.
• Answers will be collected via iClicker.
• Each students's two lowest quiz grades will be ignored in calculating final grades.

Exams

• The midterm exam will be in class on Thurs Oct 10th, 2024
  The final exam will be at 1pm on Tuesday Dec 17th, 2024
• The exams will have no time limit. Students can stay as long as they like, or (by prior arrangement with the professor) arrive early. Students who arrive early will have to stay until the official start time.
• Each exam will resemble a homework as much as possible: it will include some multiple choice questions and some long-answer questions.

Rules for Quizzes and Exams

These rules apply to quizzes and the midterm and final exams.

1. Each student may bring and consult a single letter-size "crib sheet" of facts and formulas. Both sides of the sheet may be used, but everything on the sheet must be written or generated by the student themselves. It should not contain copies of documents generated by other people.
2. For the exam you are expected to know (or write on the crib sheet) important general numbers that you might need to answer a real-world question, such as the rough cost of domestic electrical power, the power in sunlight, the output of a large power station, etc. You do not need to record detailed numbers from tables in the book or lecture slides, such as the energy density of gasoline or the atomic number of Carbon. Those will be provided if needed.
3. Each student is expected to bring a calculator to the exam. Calculators that can graph or do algebra are permitted. Calculators (e.g. cell phones) that can connect to the internet or other external sources of information are not permitted.
4. When answering a question (other than multiple choice), you will usually only get partial credit if you just write down an answer, with no justification. To get full credit you need to give reasons why your answer is correct.