Thinking about “Why?”

Why do I make physics videos at all? Why did I do it in the format I did? What should be my format going forward?

This is an important concept that I discuss in greater detail on my wiki page at http://learn.realphysics.info/My_Format. I’ll cover some of the big points here, though.

I often hear comments like, “Great video, but you’re just repeating what’s in the textbook.” Sometimes, like a recent commentator said, “you are not explaining what is in the book.”

The former comment comes from a misunderstanding about what it means to learn physics. Your job as a student is not to make some amazing new discovery, but to catch up with the discoveries already made. Electrodynamics, like many topics in Physics, is a well-defined field with well-defined problems and strategies for teaching. Countless thousands, maybe millions, of people have gone before you to excel at Physics, and they did so by following the format that the great textbook authors (like Griffiths) have condensed down into book format.

Sure, you could follow along as a professor tries to assemble all the bits of knowledge and present it in the form of a course. But without a textbook as the “spine” of that course, you’re going to miss some points, and more importantly, you’re not going to learn what the professor didn’t have time to teach. You know what I’m talking about — the bell rings, and the professor has his chalk midway through a calculation, and he begs you to stay behind for a few more minutes while he tries to show you the entire point of that day’s lecture, only to realize that time is up and there’s nothing he can do to reclaim it. He’ll just have to speed through the next lecture to make up for lost time!

Regarding explanations, there’s a common trope you’ll find in higher level math and physics books: “The proof is left as an exercise for the reader.” There are a number of reasons why authors do this, among them, the lack of space (or time) to spell everything out for you, but more importantly, by explaining absolutely every little detail, you don’t get to think about these things on your own. Oftentimes, the difference between a good physics student and a great one is their ability to fill in those blanks, answering the unanswered questions, not because it’s going to appear on the final, but because of natural curiosity. Such students also ask the unasked questions, taking their homework problems and seeing what happens if you adjust the parameters, or ask the question in reverse, or any number of scenarios.

Naturally, such students do very well on the exams, as there isn’t a whole lot the professor can do to surprise them. They have already thoroughly examined the topic at hand, and are well-prepared to work on it as if it were a solid foundation.

My main point is this: I am not here to teach you physics. No one can do that. You are here to learn physics, and you need to reach out and get access to whatever methods or materials that will help you on that journey. My videos are only one method, and not a very necessary method, on your journey. I can’t promise you that my videos will make all the difference for you, but for some small group of you out there, hearing the textbook, sometimes for the first time, sometimes for the second, will fill in all the gaps that the professor missed during his lectures due to time. Maybe my videos will be your review session before the exam. Maybe it’s a fresh perspective on the textbook. I don’t know how you will end up using them, but I know that some people find them useful.

If I were to proscribe to you a method of learning and mastering this subject, I would probably outline the following:

  1. Access to the textbook. You need to read and reread the book and work on the problems. You need to do this until you understand everything in the book.
  2. Access to the real world. You need to connect the topics in the book with the real world. This can only be really done in a lab of some sort. (I can’t give you a lab on YouTube, and demonstrations won’t really help much except to generate some excitement.)
  3. Access to your inner self. You need to struggle through the understanding until you reach a comfortable position where you gain the self-confidence that can only come from true skill.

Notice that I am not asking you to attend lectures, or turn in homework, or take tests. I’m not even recommending you watch my videos!

Some of you will do just fine reading a textbook; many, if not most of you, will not do so well. For you, you need the lectures. You need the videos. You need a partner to talk these things through with. If you’re that sort of person, I highly recommend you engage that way — but keep the textbook at the center, not on the periphery. In addition to attending lectures, taking tests, talking with friends, watching my videos, take the time to study the textbook. You simply can’t understand this material without mastering that.

Let me know what you think, or if you have comments on my strategy or approach. Thanks for reading!

Getting Started With Final Cut Pro X

I’m going to learn how to edit my videos. Up until this point, I have gotten away with simply uploading the videos straight from my camera. Being able to edit with Final Cut Pro X will open up possibilities that I’ve never dreamed of for my channel.

I’ve written an article on my wiki that has more details: http://learn.realphysics.info/wiki/Editing_with_Final_Cut_Pro_X.

You basic process is to create a library. The library will hold all the clips and such that you are going to use, so you’ll use the same library again and again for multiple videos.

Next, create a project for each video.

Then, watch your clips. Press “i” when you want to start capturing something, “o” to stop capturing. Press “e” to add it to the end of your video. Note that you can always adjust what you captured in the timeline below in “a” arrow mode, so if you’re not exact, or if you want to adjust it later, that’s ok.

With that, you’re set to start you hand at editing.

Here’s a video that covers everything in greater detail.

Where to start with my video lectures?

It’s time to start making videos again, but I don’t know where to start. There are so many possibilities to explore.

I’ve wanted to do a calculus-based physics lecture series for so long, but I know that subject’s been done to death. Still, if I put together the right pacing, it can help a lot of people improve their scores and understand the subject more deeply.

On the other hand, I never finished my electrodynamics series. There’s so many holes in there, part of me wants to start over from the beginning.

I’ll let you know when I make up my mind. In the meantime, there’s still a lot of plumbing left to do!

HTTPS with Let’s Encrypt at Hostmonster

I’m hosting my blog and wiki at Hostmonster.com. I setup SSL using Let’s Encrypt via https://gethttpsforfree.com/. It wasn’t too hard. Let me show you how to do it.

The first step is to generate an account private key. This is used to communicate with Let’s Encrypt in such a way that they know it is you.

Run the following command from your SSH session at Hostmonster:

openssl genrsa 4096 > account.key
openssl rsa -in account.key -pubout

This will generate account.key, which you should never share with anyone, let alone copy. However, you can share the public key (the output of the second command) with everyone. Copy that into the form at https://gethttpsforfree.com/ and click “Validate Account Info”.

Next, use the Hostmonster SSL interface to create a new private key. This will be the domain key, which is used for encrypting SSL traffic for your website.

Next, use the Hostmonster SSL interface to create a new CSR. Include in the CSR wildcards like *.realphysics.info, as well as the root domain such as realphysics.info. You can add as many domains as you like, but you need control over them.

Take the CSR and copy that into the form at https://gethttpsforfree.com/ and click “Validate CSR”. It will tell you which domains you’re asking for.

Step 3 involves copying and pasting commands into your SSH session, and then copying and pasting the results. Do this a few times and you’ll be on step 4.

Step 4 involves setting up your DNS TXT record for your wildcard domains, and setting up a static file for your domain names. It’s tedious, but this is how Let’s Encrypt verifies that you actually control the domain. Copy and paste the commands to your SSH, and copy and paste the results back into the form at https://gethttpsforfree.com/.

The final step of Step 4 is to finalize the request, which will give you the certificate file! Copy and paste that into the Hostmonster SSL certificates file, and you’re good to go!

Note that if you’re running WordPress and Mediawiki like I am, you’ll want to force SSL connections for signing in. You can find out how to do that with a few web searches.

Let me know if you need any help!

Types of Videos

There are two types of videos I intend to make.

The first are the magnet videos. In these videos, I make content that the web is looking for. These videos will be short and to the point, and provide pointers out to my other videos that go more in depth on the topic.

A good example of what I mean by magnet video is Dot and Cross Products, one of my most popular videos.

The other type of video will be a textbook video, a video where I lecture from a textbook. I have tons of examples of those, and I’ll be making tons more.

If there’s another type of video you think I should make, let me know in the comments below and I’ll look into it. Thanks for reading!

A New Chapter

I’ve been thinking long and hard about how to proceed with my physics videos. For a long time, I didn’t want to try to monetize my videos, but now I have discovered that I can do so without many problems.

For starters, Google/YouTube simply doesn’t pay very much for my videos. I’m going to demonetize all of my videos because I think the ads are annoying and there’s never an ad that matches my content.

Next, I’m going to setup ways for my viewers to donate their money unobtrusively, for instance, affiliate links or products that you can buy. I’ll put links to those in the description of the video and mention them briefly at the end of the video.

I may develop some products or services that might be useful for my viewers who are learning physics. This might take the form of homework helpers. I don’t know exactly what to do here yet. I’m open to ideas, of course.

Anyways, this is an exciting new journey and I can’t wait to get into it!