# Analysis of a borked lab

It happens all the time. It even happens to you. There is a new lab you want to try out—or maybe you are just modifying a previous physics lab. You are trying to make things better. But when the class meets—things fall apart (sometimes literally).

Yes. This is what happened to me this week. And yes—it’s OK.

But let’s look at the lab and go over the problems so that I can make it even better for the future.

Finding the electric field due to a point charge

This is a lab for the algebra-based physics course. It’s always tough because many of the first things they cover in the lecture class don’t have lab activities with things you can measure. Oh sure—there is that electrically charged clear tape lab, but it will be a while before they get to circuits.

So, my idea was to have the students use python to calculate the electric field due to a point charge. This would give them a safe and friendly introduction to python so that we could use it later to get the electric field due to other things (line a dipole or a line charge). It would be great.

Here is the basic structure of the lab (based on this trinket.io stuff that I wrote – https://rhettallain_gmail_com.trinket.io/intro-to-electric-and-magnetic-fields#/introduction/vector-review

You can look at that stuff, but basically I give a workshop style presentation and have the students do the following:

• Review vectors. Add two vectors on paper (not with python).
• Find the displacement vector – given the vector for a point, find the vector from that point to another point (the vector r).
• Find the unit vector and the magnitude of a vector (using python).
• Next, find the electric field due to a point charge for the simple case with a charge at the origin and the observation point on the x-axis. Do this on paper.
• Now do the same calculation with python.
• Find the electric field at some location due to a charge not at the origin (in python).
• Use python (or whatever) to make a graph of the electric field as a function of distance for a point charge. Graph paper is fine. If they wanted to, they could do the calculations by hand (or use python).
• Finally, give a quick overview of the sphere() and arrow() object in glowscript.

So, that was the plan.

Lab problems

Here are the problems students had during this lab.

• Computer problems. Yes—whenever using computers, someone is going to have a problem. In this case, it was partly my fault. There was one computer that was broken and some other ones weren’t updated. Honestly, the best option is for students to bring their own.
• I can see that there are some students that just sort of “shut down” when they see computer code. They automatically assume it’s too complicated to grok.
• Students working in big groups. I hate having 4 students use one computer. That’s just lame.
• Too much lecture. The first time I did this, I spent too much time going over vectors with not enough breaks for students to practice. I partially fixed this for the second section of lab.
• Some students were just lost on vectors.
• Yes, the unit vector is a tough concept.
• I’ve learned this before—but I guess I need to relearn. The visualization (sphere and arrow) are just too much for many students. That’s why I moved it to the end in my second section.

So, that’s it. I am going to rewrite the lab stuff on trinket.io. I am also going to change my material for the dipole stuff that they are doing next week. Hopefully it goes well. Let’s just see.

# Should We Even Be Offering Online Classes?

It’s probably clear—I’m not a fan of online classes. Honestly, I very surprised out how much emphasis universities put on creating MORE online classes.

Let me start with my fundamental idea about the nature of learning.  You can’t learn if you don’t do.  OK, I will stop you right there.  Here is what you are going to say (or at least one person will say this):

I don’t buy this learn by doing stuff.  I spent a bunch of years learning physics and we just had a textbook along with traditional lecture. It looks like I turned out just fine.

Yes, you turned out fine—but what about everyone else?  Anyway, I still think you learn by doing.  Some humans are pretty good at watching a lecture or reading a textbook and then engaging in the material in some way—maybe just inside of their heads.  I don’t know.

But here is real truth.  No one learns real stuff (like physics) by just watching a lecture or a video or a presentation.  There is no short cut to real learning.  It takes effort and struggle.  It is through this struggle (in our minds) that we change and learn.

What are these “learn by doing” things that could happen in a course?  Here are just a few examples. I’m using an example of a physics class.

• Work physics problems—as homework, or tests, or group work or whatever.
• Interactive questions.  This could be clicker questions in class or conceptual physics questions such as physics tutorials or something.
• Ranking tasks.  Students get several options for a question and they have to rank them.  Many more ideas at PhysPort.
• Card sort or speed dating problems (pretty much anything you see on Kelly O’Shea’s site).
• Find the error in someone’s physics solution—I think this is also from Kelly.

OK, you get the idea.

Can you “do stuff” online?

Yes. I believe that it is technically possible to have an online course that engages students.  It has to be possible, but I’m not sure exactly how this would work.

Maybe I’m old, but for me it’s like having a video conference?  Have you ever been in a video conference?  Surely you have.  What happens when there are perhaps 4 or 5 people in the conference and there is that ever so slight delay in communication?  I don’t know about you, but for me it ruins everything.  I can’t stand it.  It seems like it would be the same as talking face to face, but it isn’t.

This is how I feel about online learning—it seems like you could do all the things I listed above but do them online.  It just doesn’t seem to work as well.

Oh, and if your online class just takes the powerpoint lectures you use and puts them online—that just seems silly.  Honestly, why are we still using powerpoint stuff that just covers the same material as the book?

Is the future of learning online?

Maybe.  Who knows.  Maybe I’m just resisting change that will happen anyway.  I’ll say this—if the goal of learning is just to transmit information, then what the heck are we doing in class?  Wikipedia already does this better than I can.

Why are we trying to compete nationally?

Let’s just focus on local.  We can win at local.  If we (the university) want to compete online, aren’t we competing for students that could use MIT’s online programs or some other online university that does a better (or cheaper) job than us?

I’m not against videos.

In case it’s not clear, I have been putting educational videos online for a long time.  A long time.  Here is one from 2009.

My feeling is that if there is a short lecture or demo I could do in class, I might as well put it online.  That way students can watch it and rewatch it (and other people can use it too).  These videos then allow me to do more active-learning things in class rather than going over the solution to some physics problem.

But I don’t think you can just put a bunch of videos online and say “boom – online course”.  If you think that, what about just posting the textbook online and calling it a course?  It’s essentially the same thing.

What do students think?

Sometimes I talk to students. I ask them what they think about the online courses that they take.  Here are some things they say:

• I like the online courses—especially for intro courses.  That way I can get it over with and do the work from home.
• I hate online courses.  I get super confused and it’s really hard to learn.

I could be wrong, but it seems as though they like online courses for simple stuff but not for complicated courses.  Courses that are just a bunch of facts work great as online courses but not something like physics.

Perhaps we have too many courses that are just a collection of facts.  Yes, some of these courses are necessary—but it should just be a few.

Focus on community of learners.

Let me share my chocolate chip cookie model for higher education.

College is like a chocolate chip cookie.  The courses a student takes are like the chocolate chips and all the other stuff they do between classes is like the cookie dough.  What if you put all the courses online?  Then you just have a bunch of chocolate chips.  You might like that, but it’s pretty hard to call it a cookie.  Personally, I prefer the whole cookie.

The most important part of college aren’t the classes—it’s all the other stuff.  The goal of higher education is to build a community of learners (where the faculty are also learning stuff).

The end.  Change my mind.

# It’s Just One Semester at a Time

This is really for students—but maybe it applies to you also.  If so, I’m happy about that.

So there you are.  There’s still a month left in the semester (or quarter) and you are just plain burned out.  You have not motivation to study and your last test score wasn’t quite what you expected.  That thought creeps into your head—maybe you just don’t belong here.

NO. Don’t listen to that voice!

Yes, we all have that voice.  It’s in us all.  It’s the voice of doubt.  You can get through this—surely you can.

Let’s stop for a moment and consider something else.  Suppose you are in a race.  It’s a long race—maybe it’s a 10k.  You haven’t run this far before and you are worried about finishing last so you start off with a quick pace.

Oh, now it’s up to the 8 kilometer mark and you have lost it.  You have to stop.  You can’t keep up this pace anymore.

Has this happened to you in a race?  It has to me (and I hate races).  Of course the problem in this situation is the pace.  You can’t start off too fast or you will run out of energy.  You have to start off with a reasonable pace that you can keep up with the whole time.  It is indeed odd that starting off slower gives you a faster overall speed—but it’s true.

Back to studying.  You can see where this is going.  If you start off at a whirlwind pace at the beginning of the semester, you are going to run out of steam.

Here are some tips for taking care of business during the semester.

• You don’t have to be perfect in all (or any) of your classes.  That’s like assuming you are going to win in every race.  No one wins all the time—and this isn’t even a race.  It’s not a competition.
• Take some breaks.  I’m not saying you should just sit around and chill, but if you work all the time your brain can’t process stuff.  Do something fun.  Go see something.  Hang out with friends.  These are the parts of college life that will have a huge impact.
• Work with others in a study group.  This means you will help others and this means others will help you.  Both of these things are super useful.
• Exercise.  Go for a walk or hit the gym.  Personally, I like to run—and I don’t use earphones.  Just use that exercise time to sort of meditate and let your brain unwind.
• Need help?  Get help.  There are plenty of people to help you.  Go talk to your professor (they are most likely nice). Talk to your friends and family.  If you feel like things are getting out of hand, there are probably support services at your university.

Finally, maybe you like dogs.  Go find a dog and pet a dog.

# Physics and Education Majors

There is this course.  It’s called Physics for Elementary Education Majors (PHYS 142) – maybe that’s not surprising.  Anyway, I really like this course – it’s awesome.  Let me tell you a little about the history and future of this course.

According my email archive, I think this course was created in 2003.  Ok, technically it was created before that but 2003 is when we started offering the course again.  Actually, the fact that the course already existed made it much easier to get it going.  If you have ever been part of a university curriculum committee, you know what I mean.

We created the course for the College of Education.  They needed a science course for their elementary education majors that satisfied some particular component of NCATE (the accrediting agency for Colleges of Education).  I honestly don’t know (or can’t remember) what specific thing the course was supposed to do – but there it was.  This course was perfect for them.

The first semester I taught this course, I used the Physics by Inquiry (McDermott) curriculum.  This curriculum was especially designed for education majors – and it’s quite awesome.  However, there was one problem – maths.  There isn’t a ton of math in PBI but there is enough to make students panic.  I think they should indeed work through their issues with math, but it was causing problems with the course. Note: I tell students that they shouldn’t say “I’m not a math person”.

After math troubles, I decided to switch to a new curriculum.  At the time it was called Physics for Elementary Teachers (PET) but was later changed to Physics and Everyday Thinking (also PET – by Goldberg, Otero, Robinson).  Here are some of the awesome features of PET.

• Student learning based on evidence collected (not authority learning from the textbook or instructor).
• Explicitly includes ideas about the nature of learning.
• Emphasis on model building and the nature of science.
• Includes children’s ideas about physics.
• Math isn’t a barrier.
• OH, the best part.  The new version of the curriculum is called Next Gen PET.  This version explicitly aligns with the Next Generation Science Standards.  This should be a huge win for the College of Education.

Honestly, it’s great stuff.  Oh, there are still problems.  Students get caught up in the whole “why don’t you just tell us the answer?” thing – but I can work around that.

But like I said – this is the course that we have been teaching for 15 years (wow – even writing that is incredible).  This course was designed for the College of Education.  We typically have been teaching three sections of the course each semester with an average of about 25 students per section.

PHYS 142 Today

I accidentally discovered something recently.  The education majors informed me that PHYS 142 is no longer required in the curriculum.  What? How can that be?  Yup, it’s true.  The new science requirements for elementary education majors have the following three courses:

• Biology 1
• Biology 2
• Earth Science

That’s it.  I’m sure those are fine classes – but they miss a big thing.  They don’t emphasis the nature of science.  In fact, I suspect that these three classes might actually decrease the students’ understanding the nature of science.  Since these three courses have quite a bit of memorization elements in them, students might come away with the belief that science is about facts and not model building.

Yes, I’m not too happy about this.  Not only do I think this course is perfect for education majors (who will be the first to introduce science to children in many cases).  I also genuinely enjoy teaching this class. It’s great to interact with students and see them increase their understanding.  There’s nothing quite like being there when a student starts putting different ideas together.  It’s great.

On a logistical note, this course as some other huge impacts.  First – teaching load.  If we have 3 sections of this course, that would be 15 hours (it’s a 5 contact hour course).  Getting rid of the course will lose 15 contact hours for the department.  That’s one instructor position.  That sucks.

Oh, also I usually teach this course during the summer session. That’s going to suck to not have this.

# Trip Report: Texas AAPT/APS Section Meeting

Since this is just a normal plain blog, I can do silly things like this report on my recent trip.  Why not?

Where and Why?

I was invited to give the keynote address as well as a workshop on python at the AAPT/APS section meeting at the University of Houston.  Since this isn’t too far away, I decided to just drive there – it’s about a 5 hour trip.  Not bad, plus I can bring as many pairs of shoes that can fit in my car.  I brought one pair of shoes.

I drove in on Friday and arrived Friday evening – I stayed at hotel on the outskirts of Houston.

A note regarding section meetings.

I really like section meetings.  They are smaller, cheaper, and it’s easier to get around and see everyone.  Oh, national meetings are cool too – but sometimes they are just too big.  Also, who likes paying 500 dollars just for registration?  Not me.

Python Workshop

For the workshop, I used my python material.  This is essentially the same stuff I used at the Chicago Section of AAPT.  Here are some notes.

• The material basically this stuff on trinket.io.
• I also have instructor materials and other files posted on the PICUP site.
• It seems there were about 15 participants. The room had computers for people to use – that helps out a bunch.
• There was an issue with the projector – it wasn’t quite working.  Someone brought in a backup, but it wasn’t bright enough.  It’s funny how small problems like this can make a big difference when people are learning.
• Another issue for python workshops – variety of people.  Some people have never used python and some have experience. This makes it slightly difficult.
• Other than that, I think the workshop went well.  I had one person ask me afterwards how to become an expert with python.  My response was to just keep practicing.  The best way to learn is to learn python to solve particular problems.  It’s pretty tough if you try to learn stuff without a purpose.  Oh, also – sloppy code is fine.

Keynote: Science Communication with MacGyver and MythBusters

Normally, I give a talk that focuses on physics of science fiction or video analysis or something like that.  I’ve talked about science communication before – but in this case I wanted to include a bunch of examples from MacGyver and MythBusters – so I had to make a new talk.

Check out the venue (maybe it’s difficult to see from this pic though):

This is the “club level” of the University of Houston football stadium.  No, there wasn’t a game going on at the time (but that would have been funny).  It was a nice place – the screens were in a weird position, but still it was nice.  Oh, I did make one fairly big mistake.  I was having trouble with the projectors and I ended up with “mirroring” on my computer.  This means that I didn’t see the next slide and and I didn’t have a clock. I really like seeing a clock.

For the talk, I focused on 4 “rules” of science communication:

• You can’t be 100% correct, but you can be 100% wrong
• Build a bridge from the science to the audience (complicated, conceptual, or shiny physics).
• Science fiction is still fiction.
• Use mistakes as a foot in the door to talk about what you want.

Overall, I think it went well.  Oh, there was one great question at the end.  “How do we use science communication to help people understand climate change?”  My response: we need to focus on the nature of science and understanding of what exactly science is all about.

Finally, here is another picture. This is me on the football field (which was kind of cool).

# A Quick Note: Packing for College

My oldest daughter is currently in the process of getting her stuff together.  She is moving away for her first year of college.  Hope everything goes well, but I keep thinking of this scene from The Hobbit.

Yes, in college you will have to do without a great many things.  Honestly, that is part of what makes the whole college experience so great.  It’s not just about classes, but all the things in between (if it was just about classes – it would make more sense to stay home and take classes online).

No, you won’t have everything perfect in college (or in life really).  You won’t have the best shoes for a particular event.  You might have to wear the same pants more than once.  You are going to have to share a room with someone – and a shower too.

But you know what?  It’s not just college – real life is like that also.  It’s not about making everything perfect, it’s about living with what you have.  You can never have a perfect life – unless you learn to enjoy the imperfections that life throws at you.

# Update on Python Physics Curriculum

So here is the deal.  I had this idea.  The plan was to include numerical calculations into the intro physics curriculum by writing a sort of online textbook.  Or maybe just redo my Just Enough Physics ebook to include more numerical calculations.  Anyway, this is what I came up with. It’s written with trinket.io – an online implementation of python that pretty much rocks.

Here is my curriculum (it’s incomplete – but totally free).

Introductory Physics with Python

Here are some of my own thoughts on this curriculum (including using trinket.io):

• It’s free and online.  That’s mostly good – but I don’t know if online is the best format for physics.
• There is one thing about trinket.io that makes this rock.  There is python RIGHT IN THE PAGE.  Readers can view and run code – no logging in, no saving, nothing.  Just edit and run.  No barriers.
• It has the same idea as Just Enough Physics in that it goes over the basic stuff – but doesn’t overload the student with tons of different ideas (no fluid dynamics, waves, buoyancy, sound…).  It’s not that those are bad topics, it’s just too much.  Too much.
• Homework.  Students want homework questions.  I sort of added those in – but students seem to want traditional homework questions.

Now for the part that needs work.  Well, all of it needs work – it’s not complete.  But I made an error – I figured I would finish this curriculum as I was using it to teach the summer session of physics, but the pressure was too much.  In the end, I think I made it too much like the traditional format of a textbook (with the traditional order of topics).  Really, I started along the best path – but went off the rails when I wanted to do a problem that involved new physics.  So, I just added that new stuff in there.

I need to rethink just what I want to cover – and here is my new plan.

• Kinematics in 1-D and 2-D. I like starting with kinematics because students can model motion and this works great with numerical calculations.  The one problem is that you have to use acceleration instead of change in momentum – and this messes up with my momentum principle.  Actually, maybe I will just do 1-D motion so that I don’t need vectors.
• Forces. I don’t really want to focus on forces and equilibrium, but the students need this to do more stuff.  In this, I need to do the following.
• Vectors.  Boom – need vectors.
• Special forces: gravity, real gravity, maybe Coulomb force.
• What about friction, and forces of constraint (like the normal force)?  Here you can see how it gets out of hand.  Friction is super crazy if you think about it – so are normal forces.
• What if I just did simple forces – like pushing with your hand or rockets?
• Momentum Principle.  Here I need to make a connection between forces and motion.  Since I used acceleration before, I need to make a connection between the momentum principle and $\vec{F}_\text{net} = m\vec{a}$.  Honestly, I hate calling this Newton’s Second Law – it seems wrong.
• But what about circular acceleration?  How do you deal with that?  I don’t know.  Maybe just avoid it for now.
• Work Energy Principle. I think this is mostly ok – except I need to introduce the spring force and spring potential energy.
• Angular Momentum Principle.  My initial idea was to cover “Three Big Ideas” – momentum principle, work-energy, angular momentum principle.  However, there is SO MUCH baggage associated with angular momentum principle.  Much of this stuff is just beyond intro-level students.

I think I have a new plan.

• Forces – but simple stuff.  No friction.  No normal forces.  All the examples will be in space or something.
• Momentum Principle and acceleration. Again, normal stuff.  No forces of constraint.  Mostly space stuff because that will be fun.  Projectile motion stuff too.
• Work-Energy Principle.  Springs, gravity, dropping objects.  Orbits.
• Special cases.  Instead of Angular Momentum, I’m going to go over forces of constraint, friction, normal forces, circular acceleration.

The end.  Oh, I need to make sure there are plenty of exercises for students.  Rewrites coming.

I need to redo all my physics labs.  They are terrible.  I want to make them even MORE about model building.

With that in mind, I saw this:

One sentence labs.  Leave the procedure up to the students.  I think I will need some type of turn in sheet for these labs though.  What about informal lab reports?

# The worst high school physics question EVER

Here is a multiple choice question from an online high school physics question.  It’s bad, but it’s probably not actually the worst ever.

It goes something like this:

You have three objects that start at the same temperature.  Which one cools off the fastest?

1. A dry bean
2. Toast
3. Water

I’ll be honest, I answered this question incorrectly – well, I should say that my answer didn’t agree with the key.  Let’s go over the options.

Water

I’m starting with water because this is the answer I chose.  Why would water cool off the fastest?  My assumption was that the water would evaporate and cool off the liquid more than the other two objects.

Of course the evaporative cool depends on several things:

• The water temperature
• The air temperature and humdity
• The volume of water
• The surface area of water.

If I take some water and pour it into a very shallow pan with a large surface area, this stuff is going to cool off quick.  Note: here is an older post about evaporative cooling.

Toast

This was my second answer.  What is special about toast and why would they choose it?  In my mind, toast is special because it has lots of holes.  Lots of holes means that it has a large surface area to volume ratio.

Since things radiate thermal energy through the surface area, things with high surface area to volume ratios cool off faster.  This is why small objects cool off faster than large objects.  This is also why the moon’s core is cooler than the Earth’s core (the moon is smaller).

Oh, this is also how a heat sink works.  Large surface area to volume ratio.

Dry Bean

A dry bean could cool off the fastest because it is small (high surface area to volume ratio) and it is low density.  I assume if it has a low density it has a low specific heat capacity.  This means that with a low specific heat capacity, the dry bean has a small amount of thermal energy even though it has the same temperature as the water and the toast.

This is essentially the same reason that you can put pizza on aluminum foil in the oven.  Once it is hot, you can touch the aluminum foil, but not the pizza.  Although they are at the same temperature, the aluminum foil has less thermal energy to burn you (because of the low mass).

This was the correct answer (according to the people that wrote this dumb question).

Writing questions isn’t so simple

I think what the author really wanted to ask was “which has the lowest thermal energy?”  But even then, you have to take mass and specific heat capacity into consideration.

It’s really just a super bad question.  Super bad.  Oh, but it’s probably not the worst one.  I saw some others that were just as bad if not worse, but I have blocked them from my memory.