Active Lecturing

Lecturing is said to be a very poor way of teaching.  Lectures provide passive learning, whereas studies indicate that students learn more through active learning, such as working problems in the classroom.  And yet, lecturing is what most teachers do in college classrooms.

Actually, in the classroom lecturing is not as passive as is implied.  Most students take notes.  That requires summarizing the teacher’s words in fewer words.  A problem with laptops in the classroom is that students can copy down words too easily so they lose the need to summarize.  Summarizing is active learning:  the students have to work at it to summarize.  Just copying words down is passive learning; without having to work at it, the new ideas being copied do not stay with the student as well.

Teachers typically add active learning to their lectures in the form of questions.  The teacher may think of a question during the lecture and ask it. Other times, for myself, I think of questions before the lecture and add them into my PowerPoint lecture notes.  To be effective, the questions need to involve applying the concepts just presented. When I ask questions, usually only a few students will answer.  However, looking at the faces and body language, I see that many of the students are thinking about a possible answer.

An effective lecture builds on what the student already knows.  We often start out commenting on previous ideas—sometimes just by reviewing the previous lecture—and then presenting ideas that build on the old.  That approach makes my lectures understandable.

An effective lecture also relates new ideas to people’s lives.  Naturally, I try to relate chemistry to people’s lives.  Here is an example from last semester.

  1. The old information the students build on:  Remind students of how energy is treated.
  2. Intro to what we are about to do.  Tell them that the steps in something dissolving can account for for whether a solution gets warmer or colder when a salt dissolves in it.
  3. The new information.  Go through the process, presenting the new material about  dissolving taking place in steps.
  4. Relate to life.  Apply the new information to account for how cold packs and hot packs work.

Including real world examples as above makes my lectures somewhat interesting.

An effective lecture also motivates students to learn.  Yeah, but how?  After giving the above lecture I realized:  what a wasted opportunity.  I’ve been doing this wrong for twenty years.  Perhaps you can see how the pieces above could be put together to motivate the students.  The last step—the real world example—could have been placed at the beginning to make them wonder, “How does chemistry explain this?”  Like a good movie, make the audience want to know what the answer is.  The next time I present the above material I will add an extra first step.

  1. Motivate them.  Show pictures of a cold pack and a hot pack.  Raise the question of how can chemistry explain how some things release heat and others absorb it.
  2. The old information the students build on:  Remind students of how energy is treated.
  3. Intro to what we are about to do.  Tell them that the steps in something dissolving can account for for whether a solution gets warmer or colder when a salt dissolves in it.
  4. The new information.  Go through the process, presenting the new material about  dissolving taking place in steps.
  5. Relate to life.  Apply the new information to account for how cold packs and hot packs work.

Lectures can include active learning.  In an “active lecture”, students summarize the material by taking notes, students are challenged to apply the material by answering questions asked by the lecturer, and students are motivated to apply the material to explain real-world phenomena.

One way of bringing active learning into the classroom is to flip the classroom:  the students work on solving problems in the classroom and watch videos of the lecture material outside of class.  In other words, the lecture is still part of the course.  Video lectures have advantages:  the video can be re-watched and paused.  That is a big advantage and is necessary as we move toward delivering courses online.  But I think the lecture is a necessary component of college classes.  If lectures are perceived as a poor way to teach then maybe we need to get better at lecturing.

Pain-free Dentistry

Last Thursday I had a couple of cavities filled.  Wasn’t brushing my teeth regularly, and was doing a couple of bottles of Pibb each day.  I’ve since changed my evil ways.

Some years ago I thought I could conquer pain.  Part of pain is fear.  I thought if I could trust the dentist, and realize that the pain was not causing damage to my body, and realize that the pain was part of making things better, then maybe I could accept the pain.  So, I tried it:  I asked a dentist not to use Novocain.  Yes, there was some pain, but I made it through the visit.  I kept that up.  Sometimes the pain was considerable.  One time, the dentist said, “Nothing makes you holler,” or something like that.  Another time, I said, “uhh, uhhh!,” in acknowledgment of the pain.  That was years ago.  I still don’t use a pain killer.  Dr. Hendrix, my dentist here in Troy, whom I highly recommend, says I’m one of only two people in her practice who don’t use Novocain.  But here’s the thing:  there hasn’t been any real pain in years.  It isn’t me, it’s the technology!  I figured out long ago that the pain came because the drill bits got hot.  Now, the stream of water built into the drill prevents the heat:  very little pain!  In fact, the pain from drilling is less than the pain from all those mysterious appliances the dentist puts between the teeth, and between the tooth and the gum.  That’s where the future in dentistry lies:  figure out how to cut down on the pain from those “accessories”, or whatever they’re called.  Someday, people won’t even think of using drugs when they have a tooth filled.

Not using a pain killer has advantages.  I don’t have to wait for an injection to take effect, or wait for it to wear off.  After getting use to not using a pain killer at the dentist, naturally, I didn’t want drugs for other procedures.  A root canal?  Get real… of course I used a pain killer.  But a colonoscopy?  I talked the doctor out of giving me anything.  Apparently, “full anesthesia” is common in our area.  (Sedation for colonoscopy seems to be a controversial matter.)  In my case, being alert was an advantage.  The doctor asked me what those little black grains were.  “Oh, I had some black rice the other day.”  In a second matter, I had a swollen lymph node, which led to a biopsy, which was a bit tricky, because a shoulder nerve was close to the lymph node.  I convinced the doctor to go with a local anesthetic, instead of a general.  He said that ended up being beneficial, because he had been able to ask me about feeling in my shoulder, to make sure the nerve wasn’t being damaged.  (Turned out I had something called “cat scratch fever”, which goes away with time.)

Keeping Up with Technology

I use an Excel macro to send my grades from a spreadsheet to my website, where students enter a password to see their grades.  For over a year, now, the macro has not worked.  With help from our school’s IT folks, I tracked the problem down to CylanceProtect, a sophisticated malware/virus detector installed on all the school’s computers.  CylanceProtect lets macros run as long as they don’t try to write anything to the hard drive, which my macro was trying to do.  The solution is to store the macro in a particular directory (IT told me its name) where such macros are allowed to run.

Another problem with the macro was how to get a file’s location when it is stored in Microsoft Onedrive.  You’d think that would be trivial in VBA (Visual Basic for Applications), but it isn’t.   What is usually returned is a url instead of a directory.   I finally found a post telling how to get the directory path, so now my macro is up and running, again, and students can see how they are doing in my classes.

Since I’m editing web pages lately, I was, once again, wondering if there is a better web page editor available.  I’ve been using an older version of Adobe Dreamweaver at school, and Microsoft Expression (unsupported, but free) at home.  Amaya by W3C is a free, open-source editor that is OK, but hasn’t been updated since 2012.  Because Mozilla Firefox includes so many developer tools, I’ve often wondered if there is a way to edit pages within Firefox.  Mozilla now has a Learn web development section, though it isn’t easy to find.  in the “Complete beginner” section, they suggest starting with the Brackets text editor.  I’m thinking, “I don’t want a text editor, I want to edit web pages and see what the edited page looks like.”  Times have changed:  click the “live preview” icon and the content of the web page being edited is dynamically displayed in Google Chrome (or in Firefox, if experimental live preview is turned on).  I’m going to start using Brackets to create and edit my web pages.

Updating the Website

I’ve added SSL/TLS security to the website. I had to pay $50 to buy a certificate to do that (the hosting company,, doesn’t support the free Let’s Encrypt certificates).  Now, these web pages have a green lock next to them in the address bar in Firefox, and the address starts with https://, which indicates that the site is secure in regards to having entered personal data, such as passwords, picked up while the page is being transferred from your computer to this site’s server.

Yet another bit of security was required by the school:  Troy University doesn’t want data transmitted over the internet by ftp because the data isn’t encrypted, so I had to figure out how to make SSH (Secure SHell) work on this site.  Fortunately, the required key is free, but it took a while to figure out how to get my preferred client, WinSCP, to handle SFTP (secure FTP) using SSH.  Now I can transfer grades and passwords to the site without worrying about them being intercepted along the way.

I’ve been thinking of adding blogging capabilities to the site for some time, and decided to do it today, so, now, WordPress has been installed.  Since it’s open-source, there was no charge.  However, to allow comments, I needed to have email capabilities on the site, so I’ve now got an extra email address:  Fortunately, Microsoft Outlook handles this smoothly, and all my email is collected in the same “pot” as my email.