What Is the Course All About?

Introduction to Nuclear Engineering and Ionizing Radiation and what he hopes students will take away from the class. PROFESSOR SHORT: The course is all about radiation, both its origins and its uses. It’s an introduction to everything nuclear that any student at MIT would take. For many students, it's their first modern physics course, because the physics courses that first-year students take are often about things we've known for 100 to 300 years, and the field of nuclear physics is still evolving. We're still using nuclear radiation spectra to detect the presence of water on Mars or the moon. We're still confirming our knowledge of which particles do and don't exist, and why. So this is also an intro to modern physics. Nuclear science, and radiation, in particular, are emotionally charged topics. How are you preparing students to debunk pseudoscience and to really serve the public? PROFESSOR SHORT: We actually spend two weeks at the end of the class looking at studies that are false or have exaggerated claims, and teaching students what to look for. For the first 11 weeks of the class, we teach the students the fundamentals of nuclear science, and then we turn to published articles, and blogs, and other things in the field. And we debunk myths like the myth that cellphones cause cancer due to ionizing radiation. Cellphones don't emit ionizing radiation. We debunk the myth that the tiniest little bit of irradiation can harm you. In truth, we don't know that to be true or false. And it's a good thing we don't because we would need to have exposed tens of millions of people to low levels of radiation in a controlled study, which is not something that’s ethically correct to do. It's also not ethically correct to say that all radiation causes harm, because we don't know. And I want students both to recognize false science in the field, and to recognize when we don't have enough information to say something confidently and be comfortable with that lack of knowledge. The lack of knowledge means there's something new to explore. But if you don't have anything to conclude, don't draw a conclusion! On the last day of class, we often have an irradiated fruit party where I bring in fruit that could only be brought into the US because it's irradiated. There are many different types of produce, including fruits, that are irradiated. And it's the only known way to kill all of the insect, viral, and bacterial pathogens that can wreak havoc either on people or on our crops. Irradiation kills the pests, and it doesn't harm the food or make the food radioactive. When students eat foods that they may or may not have known have been irradiated, they taste good, they seem safe, and it's one of those things where, once it's personalized, it's not as scary. When you learn the knowledge and then you see it for yourself, it becomes a lot more acceptable.

Opening Knowledge Gaps in Nuclear Science

In this section, Professor Short explains his sense of the educator's role in helping students to attain fluency in a subject. What does it mean to you for students to develop fluency in this field? PROFESSOR SHORT: A cursory knowledge of radiation science is not enough. There are a lot of self-proclaimed experts who have learned a bit of genuine knowledge but then extrapolate it too far. And there are celebrities and other role models spouting falsehoods about radiation, or vaccines, or other things that they don't understand. It's important to be fluent and well-grounded in the fundamentals so that you can sort out fact from fiction. I want every student that leaves my class to be able to tell whether a claim is plausible or not and to verify if the source is genuine. How do you help students develop this fluency? PROFESSOR SHORT: It starts off with the fundamentals of radiation science. As in any class, we teach all the fundamentals from well-established theory, but along the way, every week, we have labs and personalization. For example, on the first day of class, I ask students to bring in their toenail clippings. And they usually say, “That's disgusting! What are we doing?” And I say to them, “You'll see.” We put their toenail clippings in the reactor and we irradiate them. And because, to some degree, you are what you eat, some of the elements that we eat get incorporated into our toenails. So we activate those toenails by putting them in the reactor. They absorb neutrons and give off characteristic gamma rays, revealing with striking precision how many atoms of arsenic, and selenium, and such are incorporated into the toenails. And we're even able to tell where students come from based on analysis of their toenails. We had one student whose toenails contained a lot of gold. And I said, “I thought I asked you guys to clean these off, to remove any polish.” And the student said, “Yeah, I did, but I live near a gold mining town.” I was wondering why that one student had far more gold than all the others, and it turns out it's where the student lived: it was in the water. In the problem sets, instead of saying, “Analyze this theoretical problem,” I say, “Analyze your toenails. Tell me how much arsenic and gold you've got in your body.” That's what I mean by personalization: students discover things about themselves through nuclear science. As an instructor, I like to start by opening knowledge gaps rather than spouting theory at someone. It doesn't usually stick if I just say, “Here are some facts. Learn them.” It usually goes in one ear, out the other. But when you show someone something surprising, they're fully engaged—they're multi-sensorily engaged. They're listening, in a lot of cases they're touching or even smelling. Taste is the one sense that we don't tend to engage in nuclear science—with good reason!—but you can see, and feel, and hear a lot of things in nuclear science. Yesterday, for example, I was with one of my graduate students. We were looking at some highly irradiated materials from a reactor in Idaho, and we heard a little, faint buzzing noise in the Geiger counter. And if you put your ear up to the Geiger counter near the radiation source, you can hear tiny electrical discharges. You can hear the detector working. I want the student to hear that sound and ask, “Why is that? Why do I hear this fuzzy noise near the detector when it's working?” Then, when you explain why students tend to remember. Not too many people learn well by being lectured at, but everyone learns well by opening knowledge gaps. And you're effectively letting the student pull the information in rather than trying to push it into them. Something I learned from a mentor here is you can't push a string. If you want knowledge to go into a student's brain, they've got to pull it. You can't push it.

Analytical and Laboratory Homework Assignments: Building Skills, Testing Intuition, Confirming Theory

This year, we are including a number of types of problems in each 22.01 problem set. Approximately half of each problem set will consist of simpler questions, designed to build critical mathematical, scientific, and intuitive skills to solve problems in radiation science. The other half will be alternating analytical questions of considerable difficulty, and take-home laboratory exercises where you will have to make and explain measurements related to radioactivity.

Analytical Questions of Considerable Difficulty

These will consist of open-ended questions, where you have to make key assumptions, choose your problem-solving approach, and work out the intermediate steps yourself. The numerical answers will be given in the problem statement, to help you check the validity of your approach. Grades for these problems will be based on how you set up the problems, define assumptions, and your intermediate work.

Take-Home Laboratory Questions

The laboratory component of each assignment should be submitted as a short scientific journal article. We'll provide a sample high-quality journal article, highlighting the type of organization, language, sections, and references that it should contain. Each article should contain:

• A < 100-word abstract, which summarizes the main problem and results very briefly.
• An introduction, which puts the problem into context: Why it is important (and not because it was assigned).
• An experimental methods section, where you describe what you did.
• A results section, where you show all your raw and intermediate data.
• A discussion section, where you explain your results, and you mention/quantify any sources of error.
• A conclusion section, where you quickly summarize your major contributions.

The whole laboratory report component should be no more than three pages, single-spaced in 12pt Times New Roman font or similar. Grades will be determined equally by the completeness of the documentation of the experiment, technical accuracy of the results & analysis, and the quality & readability of the report.

Working Together, Academic Integrity

Working together is OK! If you work in a team, you must:

1. Acknowledge your team members prominently in the assignment, whether it is analytical or laboratory-based.
2. Write your own laboratory articles from scratch.
3. Write/typeset your own problem sets (no xeroxing).
4. State who did which parts of the assignment. If we sense that someone is doing almost all the work, we will meet with you to prevent this sort of thing.
5. It's OK to take one set of experimental data together as a team, as long as you say who took the data.