MIKE SHORT: Instead of saying, analyze

this theoretical problem, I said, analyze your toenails.

Tell me how much arsenic and gold you've got in your body.

All we study at MIT is the natural world and things

we make out of it, so everything is reducible to practice.

Everything can be real, if you put in the effort.

SARAH HANSEN: Today on the podcast,

we're talking about ionizing radiation

and nuclear engineering.

How do you make these things real and tangible?

MIKE SHORT: Matter is a form of energy.

And once that clicked, everything

seemed to make sense-- radioactive

decay, nuclear reactions, all these things.

I remember that aha moment in this class

that I teach as a second-year student back in 2002.

And it's those kind of moments that

made me want to stay in it, because I feel like, wow, I

really know this field now.

SARAH HANSEN: Welcome to Chalk Radio,

a podcast about inspired teaching at MIT.

I'm your host, Sarah Hansen from MIT OpenCourseWare.

The Nuclear Engineering and Ionizing Radiation course

at MIT take students from understanding basic physics

to grappling with the core concepts of Einstein's E equals

mc squared.

In this episode, we're going to delve

into how this is possible, and what

it takes to make a class that's not only hands-on, but also

capable of evolving daily.

My guest is one of the main people that makes this happen,

Professor Mike Short.

MIKE SHORT: This course is all about radiation,

both its origins and its uses.

So this is the first course on its intro to everything nuclear

that any student at MIT would take.

And a lot of times for students, it's their first modern physics

course.

The physics courses that first-year students take

are often things that 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 intro to modern physics.

SARAH HANSEN: So nuclear science and radiation in particular

are emotionally charged topics, you know?

You read on the internet claims like, cell phones cause cancer,

things like that.

How are you preparing students to debunk pseudoscience

and to really serve the public?

MIKE SHORT: We actually spent 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.

So 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 cell phones

cause cancer due to ionizing radiation.

Cell phones don't emit ionizing radiation.

We debunk myths like, the tiniest little bit

of irradiation can harm you, when in truth, we

don't have the data for that.

But a lot of misinformation in radiation and nuclear science

is incorporated into culture, into our sort

of collective consciousness, and even

in what's called the linear no threshold model, which says,

every little bit of radiation does harm.

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

I think is 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 to both recognize false science

in the field, and recognize when we

don't know enough information to say something confidently,

and be comfortable with that lack of knowledge.

It means there's something new to explore.

But if you don't have something to conclude,

don't draw a conclusion.

SARAH HANSEN: Uh-huh.

How does this connect to the irradiated fruit

party that have in the class?

What is that?

MIKE SHORT: Yeah.

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.

So there are many fruits that are--

there 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 on either people

or on our crops.

An interesting point of information, Hawaii

and Puerto Rico, despite being part of the US,

are agriculturally distinct areas,

and you are not allowed to simply

import produce from those.

I had an apple confiscated from the airport in Puerto Rico

when I learned that to be the case.

However, if you irradiate foods, like,

this is why we can get a lot of pineapples from Costa Rica.

We've started getting mangosteens

in from Thailand, where I didn't know what that fruit was

until a few years ago and now, you

can find them at H Mart in Cambridge.

A lot of this is because we can kill the pests,

and it doesn't harm the food.

It doesn't make the food radioactive.

But a lot of this is to personalize the science.

So when students eat food that they may or may

not 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 yourselves,

it becomes a lot more acceptable.

SARAH HANSEN: Yeah, learning through experience

is very powerful.

What does it mean to you for students

to develop fluency in this field?

MIKE SHORT: It's important to be fluent in this field

because a cursory knowledge of radiation science

is not enough.

I'd say there are a lot of self-proclaimed experts--

I call them armchair PhDs--

who have learned a bit of genuine knowledge, but then

extrapolate it too far.

And that combined with all the things

we've heard in pop culture, unfortunately

sometimes from celebrities spouting falsehoods

about radiation, or vaccines, or other things

that they don't understand, people listen to other people,

and people listen to role models and folks that they look up to.

But it's important to be fluent and well-grounded

in the fundamentals so that you can sort out fact from fiction.

And I want every student that leaves my class

to be able to recognize something that's incorrect,

even if it's told to them by a celebrity, an expert, a parent,

a friend, anyone--

that they know what the reality is, and it shouldn't depend

on the source it comes from.

They should be able to tell whether it's real or not

and verify if the source is genuine.

SARAH HANSEN: Uh-huh.

And how do you help students develop this fluency?

MIKE SHORT: So it starts off with the fundamentals

of radiation science.

So like any class, we teach all the fundamentals

from well-established theory.

But along the way every week, we have labs and personalisation.

Like, for example, the first day of class,

I ask students to bring in their toenail clippings.

[MUSIC PLAYING]

And they usually say, that's disgusting.

What are we doing?

And I say, you'll see.

We're going to put them in the reactor.

And we irradiate their toenail clippings.

And because to some degree, you are what you eat,

some of the elements which we eat and we don't want to,

things like arsenic, or selenium,

or chromium, some of which can be good in small amounts,

bad in large amounts--

others like arsenic, I'm not sure

if there's a good use of it--

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,

giving away how many atoms of arsenic,

and selenium, and such are incorporated into the toenails

with striking precision.

And so we're able to tell where students come from based

on analysis of their toenails.

We had one student who had a lot of gold in their toenails.

And I said, I thought I asked you guys to clean these off,

remove any polish.

And the student said, yeah, I did.

But I live near a gold mining town, and it's in the water.

SARAH HANSEN: Wow, that's so interesting.

MIKE SHORT: So that's what I mean by personal,

is they discover things about themselves

through nuclear science.

In the problem sense, instead of saying,

analyze this theoretical problem, I said,

analyze your toenails.

Tell me how much arsenic and gold you've got in your body.

SARAH HANSEN: Right, right.

So in the course, you make a point

of saying that the method of instruction

is often context first, theory second, and then context again.

How does that relate to that method of instruction?

MIKE SHORT: This is an example of that method of instruction.

I like to start by opening knowledge gaps

rather than spouting theory that someone.

It doesn't usually stick if I just say, here are some facts.

Learn them.

That's usually in one ear, out the other,

if they're listening at all.

But when you show someone something surprising,

they're fully engaged.

They're always multi-sensory engaged.

They're listening.

In a lot of cases, they're touching, in some cases,

even smelling.

Taste is the sense that we don't tend

to engage in nuclear science, with good reason.

[CHUCKLES]

But you can sense, and feel, and hear a lot

of things in nuclear science.

Like yesterday, I was with one of my graduate students.

We were looking at some highly irradiated materials

for a reactor in Idaho, and we heard this 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.

And then I want the student to say, 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 pulling the information in rather

than us pushing it to the students.

Something I learned from a mentor

here is you can't push a string.

You want knowledge into a student's brain,

they've got to pull it.

You can't push it.

SARAH HANSEN: You made a choice in this iteration of the course

to offer students the ability to do analytical homework

or take-home, hands-on labs.

How did that work out?

What does that look like in practice?

MIKE SHORT: Interestingly, I spent all this time

making these optional labs.

Nobody did them.