Category learning

Physics Explained: Video Update

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I don’t know if you have been paying attention, but I started a second youtube channel. My idea was to split my videos. Right now, I have MacGyver stuff and science demos on my “Rhett Allain” channel—but I will move all the physics calculations to a new channel. Yes, the new channel is called Physics Explained.

Basically, Physics Explained is going to start off as the content portion of an algebra-based physics course. Actually, I will use these videos this summer during my “remote learning” physics course. You can think of this as a video version of a textbook that I would write.

Right now, I have enough for the first semester of physics. I will probably add more, but it’s good enough. Also, I changed my channel name—that means some of the older videos say “Just Enough Physics”. I’ll probably go back and redo these.

If you want to go through the first semester, here is “chapter 1” as a playlist.

Here are some of my favorite videos from that group of content.

Yes, I like to include numerical calculations with python—it’s what I do.

Now, I have started to work on the second semester of physics—you know, electric fields and magnetic fields and stuff.

My goal is to get up to 1000 subscribers—if you are interested, just hit that subscribe button.

Remote Physics Labs

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This is not a normal semester. So, how can you move your physics labs to a remote learning environment? Here are some ideas.

What is the goal of a lab?

This is what we should always consider when making any changes to a curriculum. What are we trying to do. Or, in the words of Arnold Schwarzenegger:

“Who is your daddy, and WHAT does he do?”

Kindergarten Cop

So, why do we have labs? Honestly, I don’t know. Here are some thoughts:

  • They gives students a “hands-on” opportunity to explore the physics from their lecture class.
  • Students can get experience with certain pieces of important equipment—oscilloscopes, meter sticks (kidding).
  • The nature of science. How do you learn about science without doing science? In labs, students can design and build their own experiments (ideally).
  • Science communication. This is what a lab report is supposed to do—but even having students share ideas in class can be super useful.
  • More time with physics.

I don’t the answer here. Also, if the lab is a service course for some other major then I guess that other department should tell us what they want out of the lab.

Now for some remote lab ideas.

Online labs

What if students had some type of online lab? Maybe they could play around with some virtual lab equipment to collect data. I’m thinking about the PhET simulators. They have some pretty sweet circuit simulators. Students could build a circuit, measure voltage and current and do a bunch of stuff. Not bad.

There’s also the great Pivot Interactives videos. These are pre-made video experiments with measurement tools built in. Students can use the video and measure stuff like the time it takes a ball to fall or the period of a pendulum. This stuff is really nice.

Oh, there’s also Second Life. Physics labs in a virtual reality. I’m mostly joking, but maybe…

Numerical Calculations

This is the perfect time to have students solve some physics problems with python (or some other method for numerical calculations). I honestly think this is great thing for lab anyway—I’ve used these in classes for a while and they are quite successful.

Here is my numerical calculation jump-start guide.

Give them the data

What if you show a video (or two) of the physics and then just give them the data? So, let’s say you are looking at the magnetic field due to a bar magnet or a wire carrying current. Normally, students would use a magnetic compass to plot the magnetic field as a function of distance.

I could record the compass deflection values for different distances and then let them do the analysis. I don’t think this such a bad option. You can use the labs that you already have and then you just need to include some extra pictures or videos and then a data table.

At home labs

This seems like a great idea, but you might have to be flexible. Suppose you want to study pendulums—surely students can find some string with a mass on it to swing back and forth. They could find the time with their phone. What about the length of the string? This might require a little bit of thinking to get it to work—but I would suspect that most students could do it.

Another option is to have students think up their own labs. Maybe they could take inventory of their supplies and use that. Don’t forget of all the sensors on a smart phone—I’ll suggest PhyPhox as a great app.

COVID-19 Remote Teaching Update

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There’s so much going on right now—so, I think I should post this update about my plans for remote learning. Our current situation at my institution is that we are directed to transition all of our courses to “remote” learning—fortunately, we have the freedom to define how this is done ourselves.

This semester, I have two “lecture” courses and two labs. I’m going to treat these different.

Labs – Algebra-Based 2nd Physics (Electricity and Magnetism) and Calc-Based 1st Physics (Mechanics and Stuff)

How do you do a remote lab? Oh, sure—it’s very possible to come up with some things students can do outside of the lab. Actually, these make great labs in general. However, we don’t have a bunch of time to make this stuff work. So, here’s my plan.

  • Pick a set number of labs to offer the students. There were probably about 6-7 labs left in the semester, so I’m going to try and offer that many to the students. I will recommend that students try to complete 4-5 of these labs. They can pick which ones to finish.
  • For some of these labs, I will simply give the student the data that they would have otherwise collected. If there is some type of complicated equipment, I will hopefully make a short explanation video.
  • For other labs, I will give students suggestions on how to complete the lab at home. For instance—use stuff to measure the speed of sound (with uncertainty). Or measure the strength of a magnet. There’s a very good chance that most students could find material to complete these.
  • Finally, there are labs that focus on numerical calculations. Students can do these anywhere (and they are great).

Oh, what about the lab report and the final exam? For the lab report, they just need to turn in one formal lab report to be graded. The final exam will be on paper and the students can just answer the questions on paper and send me a picture of their test (or mail it to me or something).

“Lecture” Courses—Physical Science and Physics for Elementary Education Majors

Both of these course are only partial lectures. The Physical Science course shows short videos of experiments and then the students discuss the evidence and participate via multiple-choice clicker questions. It works well.

The other course is basically the same thing except that the students conduct small experiments to collect their own data.

So, what am I going to do with these classes? Fortunately, the curriculum has these video experiments online. I’m going to just cut down the material and make a new schedule (removing activities that aren’t completely necessary). With these videos, the students can still do the same activities. Once a week (or when necessary), I’ll have an online group meeting where students can discuss the experiments and ask questions.

Hope that works.

Summary

My remote learning plans can be summarized as two main points.

  • Don’t be a dick.
  • Make things as simple as possible—no need to destroy yourself over this bad situation.

Just Enough Physics Video Update

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Perhaps you haven’t noticed, but I’ve been trying to make a bunch of physics videos. Oh, sure—I already have a ton of stuff on youtube, but it’s not linear. For my old stuff, I will solve a problem on work-energy and then do electric field stuff and then go back to kinematics. It was just whatever topic came up in class or online or whatever.

I figured I should start over and do a whole physics course—well, not EVERYTHING. No, I would do just enough to get you through the course. I hope you get the title now. Also, this is the title of that self published ebook I wrote a long time ago—since it really is the video version (but updated).

So, where am I now? I’ve got 4 chapters completed. I think it’s a pretty good start. Here are the chapters (as playlists) along with descriptions.

Chapter 1: Kinematics

Notice that I started off by making a title screen and all that cool stuff. I will end up dropping this so that I can make videos faster. Also, in my previous videos I was in front of a whiteboard. In this case, I’m writing on paper. Still not sure which way is better.

In this chapter:

  • Introduction.
  • Constant velocity in 1D.
  • Example of constant velocity.
  • Introduction to numerical calculations (1D constant velocity).
  • Constant acceleration in 1D.
  • Numerical calculations with constant acceleration (in 1D).
  • Solving the “cop chasing a speeder” problem.

Chapter 2: Forces and Motion

It’s tough to start in physics with forces. There are so many things to cover. This is a shorter chapter that looks at the fundamental ideas of force and motion.

  • Introduction to forces and motion. I really like this first video. It’s a conceptual look at the forces, the momentum principle and “Newton’s 2nd Law”. Guest appearances by Galileo, Aristotle, Newton.
  • Forces in 1D – falling objects.
  • Modeling the motion of a mass on a spring (and finding the model of a spring force). This one is long (but pretty nice).

Chapter 3: Vectors—2D and 3D Stuff.

The goal here is to expand kinematics into using vectors—but then you need to know about vectors.

  • Intro to vectors.
  • Kinematic equations with vectors.
  • Example of constant velocity and position update formula in 3D.
  • Intro to projectile motion.
  • Finding the range for projectile motion.
  • Numerical calculations for projectile motion.
  • Acceleration of a block on an inclined frictionless plane. This is an example of forces in 3D.
  • The physics of flying R2-D2. Using forces and air resistance.

Chapter 4: Calculated Forces

There are really two kinds of forces. There are forces that have an equation to determine the vector value (these are calculated forces). Then there are forces that don’t have an explicit equation (forces of constraint). This chapter just focuses on calculated forces.

  • Universal gravity.
  • Example of gravity—calculating the net force on the Apollo 13 spacecraft.
  • Introduction to visual objects in VPython. This is a setup for the next video.
  • Modeling the motion of an object near the Earth.
  • Modeling the Earth-moon system.
  • Mass on a spring (again) – but this time with visuals AND 3D motion.

Numerical Calculations in Class

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You are probably tired of hearing me talk about numerical calculations. Sorry about that—I just get super pumped up.

This week, I did my “Intro to Numerical Calculations” in physics lab. I think it went pretty well. In case you haven’t seen my stuff (here is a quick start guide), here are the important deets.

  • It’s a workshop style presentation. I show something and then let the students do stuff.
  • Using python of course. Everything is on trinket.io (all the questions too—you can see that stuff here).
  • I start off with a super simple case of a cart moving with a constant velocity in 1D and then work my way up to free falling objects (with graphs).
  • There’s no 3D visualizations—even though VPython is awesome at this.
  • Even though this is the calculus-based physics lab, I used my material for the algebra-based lab. It’s a good place to start and I really didn’t have much time to make new stuff (I just picked up this lab on the first day of the semester—yay).

So, that’s that. But I really love this stuff. It’s great to see students that start off with little or no programming experience—heck, they even have trouble with the basic physics (and that’s OK). They really struggle modifying code to get things to work. They want to quit.

But they don’t quit. They start trying something. “Hey, can you make any color for this graph?” Yup, just use a vector color. Oh snap—you just used a vector.

I walk around the room and observe students. They start having discussions. It’s not about stuff like “how do you make a while loop?”—it’s more like “why is the velocity negative here?”. They are writing computer programs, but most of the talk is about physics. I’m always surprised about this aspect of their interactions.

At the end, they have some code. It solves a problem, it’s their code. They feel accomplished.

Spring 2020 Class Update

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Before I forget, I want to make some comments about my courses this semester.

Physics for Education Majors (PHYS 142)

I love this class. It’s one of my favorites. Just in case you aren’t familiar, it’s a course designed for elementary education majors (you could probably guess that from the title). We are using Next GEN Physics and Everyday Thinking (Next GEN PET). Oh—it’s awesome. Seriously, you should try this curriculum.

So, this semester things are going great so far. I normally teach this every semester, but last semester my section was cancelled. Apparently some particular college decided not to make this a required course (even though I made this course 12 years ago to satisfy their accreditation requirements). But by not teaching it last semester, I realize how much I enjoy it.

Oh sure, this semester it has much fewer students. However, I can have actual conversations with them as they work on the material. Also, the students have time to work on stuff. In the first unit they are building models of magnetism. It takes time to properly magnetize a nail. It’s slow process. I think more learning needs to take this slow process.

Special Topics: Numerical Calculations

Oh wait. This course was canceled. Damn.

Physical Science (PHSC 101)

I taught this class last semester. It went well enough.

This semester is a little different. Well, just one small difference. Instead of a large lecture class with desks and stuff, it’s a smaller room with tables. Here—take a look at this picture.

Surprisingly, this makes a HUGE difference. Now students can very easily have short discussion with other students. It makes a big difference. I like this room so far.

Intro Physics Lab 2 – Algebra-Based (PLAB 194)

I can’t just leave a lab alone. No, I have to change it every time I teach it. This semester, I want to focus more on building circuits. So far, they have only done the electric field mapping experiment. It seemed to be not too bad.

I don’t have anything else to see.

Intro Physics Lab 1 – Calc-Based (PLAB 223)

I picked this lab up at the last moment (because of the other canceled course)—so, I really didn’t get a chance to prepare ahead of time.

It’s a 3 hour lab (unlike the 2-hour algebra-based lab), so that’s kind of cool. My plan is to really focus on model building (with tons of python). It’s gonna be great. I hope.

Oh, even advanced students have problems making linear graphs.

That’s enough for now. I’ll keep you updated.

Just Enough Physics Video Series

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I think I need help. I’m not sure of the best way to proceed (or even to do it at all) with this new video project. Here is my idea:

  • Just Enough Physics – the video. Yes, a long time ago I put most of my physics explanations into a self-pub ebook on Amazon. I think it turned out OK. The book is in the KindleUnlimited program, so you might be able to get it for free – https://www.amazon.com/Just-Enough-Physics-Rhett-Allain-ebook/dp/B0052UKTDQ/ref=sr_1_1?keywords=just+enough+physics&qid=1578932997&sr=8-1
  • I’ve made a bunch of physics videos—but they aren’t well organized and they jump over to many different topics. I wanted to start over and make one series of videos that sort of go through the full intro (algebra-based) physics course.
  • In most of my previous physics videos, I used a white board with me in front of it. I think this works well, but I wanted to be able to make videos from home. With that, I decided to switch to a paper and pen method (with the camera just looking at the paper).
  • Also, I figured I would add a Patreon page. It would be nice to be able to work on this over the summer instead of teaching summer classes (which is always a financial gamble anyway). Oh, here is my Patreon page—https://www.patreon.com/justphysics

So, that’s the idea. Here you can check out what I have so far.

Now for the questions. Here’s where you can help.

  • Should I start a NEW YouTube channel for these videos or just include them in my current channel. I’ll be honest—I thought it would be good to start a new channel, but I need a bunch of subscribers before I can put ads on the videos. Yes, that’s silly.
  • I started off with an intro to each video and included a title animation. Forget that—too much work. I don’t think people REALLY care about that stuff.
  • What about Patreon? What kinds of things should I put there? Should I include access to a discord group?
  • Titles. How should I title each video? Chapter 1 section 1 kinematics? Constant velocity? I’m not sure. What about homework videos (example problems).
  • I’m aiming for each video to be about 10 minutes long. Is that a good time length?

Finally, here is my tentative outline for videos.

  1. Kinematics in 1 Dimension (including numerical calculations).
  2. Forces and the Momentum Principle in 1D.
  3. Vectors
  4. Calculated Forces: gravity, springs, real gravity.
  5. Falling objects air resistance.
  6. Forces of Constraint: normal force, friction, tension
  7. 2D Motion: projectile motion, circular motion.
  8. Orbits.
  9. Work-Energy Principle.

That’s just a start.

Course Reflections: Physical Science (PHSC 101)

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The Course:

This is a 3 hour lecture-based course for non-science majors. I used the super awesome Next GEN PET. I feel like I have talked about this curriculum a bunch (since it has content similar to PHYS 142—physics for education majors). Here are some key points.

  • Content based on the Next Generation Science Standards. For me, this isn’t such a big deal—but it can be for those adopting the curriculum.
  • This is an interactive lecture-based course. This semester, I started with 50 students.
  • Students are supposed to have a workbook that they write in. We have a textbook rental system though. In order to prevent the students from buying a book (which would be about the same price anyway), I had the bookstore make the workbook into a non-writable rental book.
  • The course covers: Energy, Forces, Waves, Light.
  • Students are presented with videos of experiments and then asked a series of multiple-choice “clicker” questions.

The Good:

Let’s be honest. Most courses for non-science majors don’t really help them understand the nature of science. Based on my own informal measurements in the past, students’ understanding of science decreases after the course. That’s bad. It’s probably because they just see science as a bunch of facts that need to be memorized.

This course focuses on the model building aspect of science. Students collect data (from the videos) and use that to justify a model—rather than just being told an idea.

The course also encourages critical thinking and uses student discussion during class. I feel like there were a good number of students that really got something out of the semester.

Oh, one more “good”. I am part of an FOLC (Faculty Online Learning Community) – https://nextgenpet.activatelearning.com/about/faculty-online-learning. My discussions with them were great.

Homework was better than I thought. I used the online activities that come with the curriculum and then I created “turn in” sheets for the students. These were simple questions based on the online stuff. Many students didn’t do it and some copied—but it helps them realize they need to do the HW.

The Bad:

Although the content is essentially the same as the studio-class version of the material, I don’t have much experience with the lecture version. Here are some other random notes about things that didn’t work out so great.

  • Clickers. I started off using the TurningPoint clickers (we already had these). For some reason, the receiver didn’t work on my macbook anymore (software update). Then later in the semester, they updated the PCs in the room and BOOM—clickers didn’t work there either. I eventually switched to plickers (https://www.plickers.com/library).
  • Student discussions. I need to get better at this part of the job (quote from Spider-Man: Homecoming). I just feel like there are small things in the class that can really throw off a class discussion. It’s tough. I need to start off with this more at the beginning and fight through the rough parts so that students get more accustomed to discussions.
  • Student participation. There are too many students that think they are watching a movie. They just sit there and play on their phone. I see them.
  • The workbook. I already mentioned that they didn’t really have a workbook. Towards the end of the semester, I started creating 1-2 page “notes” that had spots for them to write down the important stuff. A couple of students said they liked this.
  • Multiple-choice tests. I hate these.

The Future:

Here are the changes for the next time I will teach this course (next semester).

  • Change the content. I would like to cut out some of the activities and do more of the engineering-design activities.
  • Smaller room. Yes, I will be teaching the lecture-based course in the studio room. I would like to replace at least some of the videos with actual experiments.
  • One of my FOLC colleagues gives writing assignments. She tells the students to find some application of the content in real life. They have to submit a certain number of these and she just grades a few. I want to do this.
  • Plickers are better.

Course Reflections: Introductory Calc-Based Physics (PHYS 221)

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The Course:

This is the calc-based physics course (the first semester). The students in the class are mostly:

  • Physics majors
  • Chemistry majors
  • Computer Science majors
  • Math majors

I don’t think there are any other students that take this. OK, I guess you could include pre-engineering—but technically they are still physics majors.

For the textbook, I use the super alpha awesome book Matter and Interactions (Wiley – Chabay and Sherwood). If you’ve read my stuff, you should know that I LOVE this book (and Bruce Sherwood and Ruth Chabay are both great people to talk to). Here is my previous review.

Just a few highlights of the curriculum.

  • Includes relativistic momentum and energy.
  • Focus on fundamental interactions and fundamental particles.
  • Ball and spring model of matter.
  • Three big principles: momentum, work-energy, angular momentum.
  • Explicit inclusion of numerical calculations.
  • I use Standards Based Grading with options for students to submit reassessment videos.
  • We often use multiple-choice questions in class with student response systems (clickers). Matter and Interactions has a nice set of questions to use.

Here is the course website.

The Good:

I always enjoy this course. The students are both diverse and great. They are at LEAST in Calc-I so that means they can probably do some algebra stuff. There are a good number of students that are in even more advanced math classes like Differential Equations and stuff. Oh, and it’s a great chance to get to know the new physics and chemistry majors.

The class isn’t too big (mine started around 30) so that it’s fairly easy to memorize names.

Maybe the best part of the class is watching student videos. OK, I really don’t like watching videos—it can get kind of boring. But I LOVE seeing students make terrible videos and then get better and start figuring things out. It’s awesome when students have never made a video and are afraid to do it, but then really get into it.

Students eventually figure out that I’m not just assessing their videos, but they are learning by making the videos.

One other thing I liked—I always like it: speed dating physics problem solving. Here is a twitter thread on speed dating (from another class).

Also, I did assign and collect homework. I didn’t really grade it (I gave them a score), but it’s like free points and maybe it helps them practice.

One last “good”. I put together this video tutorial on numerical calculations that looks at an object falling on the surface of the moon. I think it’s pretty good. Not sure how much the students used it though.

The Bad:

Yes, there was some bad stuff. Sometimes I felt like students were just sitting there. Even when I was doing interactive activities, they had this blank stare (it seemed). Maybe it was the class time (9:30 AM)—although that doesn’t seem too early. I really don’t know what the problem was. For the most part they were fine.

Another big problem—speed dating. Oh, I get it. Students don’t want to participate. They want to just sit there and take in the fire hose of learning (they think that works). But in the end, most of them seem to get some positive things out of the speed dating. But the room was not super great for this. It’s a standard lecture hall—so I didn’t really have places to put boards. I tried using very small boards, but it just wasn’t perfect.

One final problem—a good number of student just never seemed to fully grasp numerical calculations.

The Future:

Here are some ideas for the future.

  • Mounted white boards. If I have to be in that lecture hall, I want to find some ways to put boards somewhere around on the walls.
  • Plickers. I’m ditching the TurningPoint clickers. I’m tired of constant updates that bork the system. I get it—they want me to upgrade. Not upgrading again. Oh, also with Plickers it shows the student name over their head when they vote.
  • More in-class stuff. More group problem solving. More activities. More focus on numerical calculations.
  • I should show the students more of the awesome physics (like stuff from my blog). I don’t do this enough because I get so busy with getting through different topics—but I think the students really like these things. Who cares anyway, it’s the stuff that I love.

Course Reflection: Astronomy (EASC 102)

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It’s the end of the semester, so that means it’s time to reflect on my courses. Why not just write this as a blog post? That’s what I will do.

The Course:

I’ve already talked about this course when I started the semester. So, here is a short review.

  • It’s a service course for non-science majors. There are no pre-reqs, so you can’t include much math.
  • The course was added late, there were only 13 students in the course.
  • I had a room that was more like a lab or a studio rather than a lecture hall.
  • As I said before, this is a tough class. The material seems fun, but it’s really deep. You can either cover superficial things—like known values of planets or you have to really get dirty. You can’t understand a star without knowing some important stuff about light and matter.

The Good:

The best part of the course was the flexibility. I could pretty much do whatever I wanted since they didn’t need anything from this course for future classes.

The other things that worked well were the labs. I mean, what the heck. Why not do a lab in the lab room? I started off with some of the University of Nebraska online activities—but I think these are too high of a level for my students.

After that, I went to make up my own labs:

  • Solar panels
  • Angular size
  • Parallax
  • I did a stellar properties lab – it was sort of a modified University of Nebraska lab.

I think the students liked the labs for the most part. Oh sure, there were a couple of students that just said “screw these labs—not going to participate” but there’s not much you can do about that.

Another thing I worked on was simplified presentations. The powerpoint slides that come with the textbook pretty much suck. They have too much stuff in them for the students to really learn anything. It’s not that my slides were much better, but I did include some of the online applets and animations in them.

Since the class was small, I had a better chance to interact with individual students. It’s always nice to get to know people. I admit that I didn’t learn names as well as I usually do.

In the last few weeks, I started using multiple-choice voting questions in class. I think this is the way to go. The questions I was using were probably too difficult for the students. Quick tip: use plickers (voting cards). When you scan the cards with your camera, it also shows student names.

Oh, one more thing. I think I did make some progress on student understanding of the nature of science. Really, this is the most important aspect of the course.

The Bad:

I already mentioned the bad powerpoints and the material is too deep. The other big problem—student understanding of graphs, math and stuff like that. It’s tough to do a lab that involves graphing when they can’t graph.

Although I had fun with the lectures, some students fell asleep.

The Future:

Let’s say I was going to teach this course again. What would I do? Here are some ideas.

  • Pick fewer topics. I think it’s best to stay away from stars and stuff. It depends on too many background ideas.
  • Do more labs. I would probably need to make the labs myself.
  • I think making some stuff that’s similar to PET would be perfect for this class. In fact, I did some labs like this for forces and waves.
  • I would like to do some type of project, but I’m afraid what the students would turn in.
  • DON’T USE the textbook or the powerpoints. They are terrible.