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Ars longa,Vita brevis.
Knowledge/Art is long, Life is brief
by Ken Cheney
sketch of wind-up man lecturing
Introduction *
A. Explanation of the content of this section: *
B. About the author: *
C. About this essay: *
Why Lecture? *
E. Learning styles: *
What do you want to teach?? How deeply?? *
A. Why are the students taking the course? *
B. What are the backgrounds of your students? *
C. What are their native languages?*
D. Do they have the background necessary for your course? *
Macro Structure: Large scale structures for the course and lectures: *
B. NARRATIVE (story telling, personal experience, anecdotes, humor): *
C. Historical *
D. Derivations *
E. Observations >> Theory versus Theory >> Observations *
Micro Structure: Procedures and activities for good lectures: *
A. "Tell, Tell, Tell" *
B. Methods of presenting the material and involving the class *
C. Helpful activities and methods during class: *
1. To encourage class participation: *
2. Teacher’s activities: *
3. Student presentations: *
4. Learn by doing *

1. Lecture Demonstrations *
2. Microphones and Speakers *
3. Chalk boards, and/or white boards: *
4. Overhead Projectors *
5. Slides *
6. Pictures from computers with a digital projector *
7. Videos *
8. Presentation software for computers: *
Classroom Management *
A. Classes differ *
B. Seating *
C. Taking roll *
D. Nightmares *
1. Example from the top: *
2. Late students, and early leavers: *
3. Talking *
4. Over Argumentative *
5. Questions you feel you should be able to answer but can’t *
6. Questions about sticky points in your subject *
7. You forget a vital step in your analysis or derivation or your results come out backward *
8. You never could understand this argument *
9. Everyone flunks the first test *


A. Explanation of the content of this section:

This "Lecturing" section discusses the presentation of information by the instructor with student responses. A number of modes of student involvement are discussed along with topics of classroom management. "Lecturing" overlaps with testing, homework, extra credit, etc. so these topics are also discussed as appropriate.

B. About the author:

It’s probably worth knowing something about me so you can take my advice with the proper amount of salt.  I’m a physicist by profession. I’ve taught at Pasadena City College for over thirty years and am still trying to master teaching, physics and computing. I worked for four years in aerospace in the 60s and a summer at JPL.

We teach four different physics sequences at PCC that range from "Physics for Physics Majors" to "Physics for Poets (or voters)." We take the latter course very seriously, and enjoy working with students from many backgrounds and with many majors.  "Physics for Poets" is almost entirely non-mathematical and so is utterly different from my (and all physicists’) education, which centered on problem solving and experimental techniques.

Our Physics and Engineering majors regularly go to Cal Tech and to various University of California campuses.  Physicists have been and still are very active in experimenting with new modes of instruction. As physicists, they regularly attempt to measure the effectiveness of their methods. As with much of education, everything seems to work for the inventor and his/her disciples. 

We at PCC have been quite conservative in our lecture methods, but have experimented considerably with laboratory instructional methods. It has been said that if experiments wiggle it’s Biology, if experiments smell it’s Chemistry, and if experiments fail it’s Physics. This, at least for Physics, has a considerable element of truth.  An experiment that can’t fail isn’t really an experiment: demonstration, example, practice, but not experiment. Of course, designing experiments that can fail without making the students fail is something of an art.

C. About this essay:

1. Apology

If I seem overly negative about the habits of students it is because you need no help with perfect students. Perfect students will learn everything, think deeply about the implications, and ask perceptive and pertinent questions regardless of how you teach. What we are concerned with here is how you and less than perfect students can survive and flourish.

2. The style of this essay:

Following my own advice about presentation styles, I have written this essay informally in the first person with liberal use of personal examples and opinions. The reader should keep in mind that they are personal opinions; little is certain in education! My examples are, unfortunately, heavily weighed toward math and science. This selection simply reflects my experience, not my opinion that one field has a monopoly on good or bad practices.

3. "Missing" topics:

"Pitfalls" are discussed in many sections so they do not have a section of their own, except perhaps "Nightmares".

"Learning styles" has a short section, but contrasting styles are also discussed as appropriate in many sections.

Why Lecture?

There is a lot of very convincing evidence that lectures are quite ineffective in imparting knowledge.  Why then should one lecture?

Schools are traditionally organized around a lecture structure so it is hard to avoid lecturing. And, we teachers have generally been trained by lecturing so it is natural to do what we observed. If we are training future college teachers, we are probably working with students who have by nature or training learned to flourish in a lecture environment. If we are teaching future poets, mechanics, dental technician, . . . our familiar mode of instruction is probably wildly inappropriate.

More positively -- in spite of films, TV, video, laser disks, DVDs, etc. -- live theater is alive and well. Many people voluntarily go to live lectures!  Evidently there is an emotional element in "interacting" with a live presentation that is lacking in even the best canned presentation.  If we are to be effective in lecturing, then we must take advantage of this emotional element and interaction, not simply repeat what can be read in the book.

In many cases what is really important about education is not the detailed knowledge (forgotten immediately after the exam), but the attitudes about knowledge with which the student leaves.

Learning styles:

"Experience is directly related to equipment ruined."

There are many possible ways to learn: hard knocks, from lectures, from personal experience, from theory, from books, from working problems, from researching while preparing a paper, from actually writing a paper, from preparing a lecture, . . .  There are also many ways to input data which may lead to learning: listing, reading, doing, observing schematics, cartoons, documentaries, commercial films, educational files, surfing the Web, etc.

How do you decide which style is appropriate for your audience?  Richard Feynman, the most revered lecturer on physics of the last century, said that he tried to use all styles. He said he hoped each of his audience would be hooked by at least one style of learning. While some students might be bored by a historical approach and wait for the mathematics, other students would respond in just the reverse way.

As we go through the many aspects of lecturing, I will suggest methods to appeal to many different styles of learning. Keep experimenting with each class, and see what works for you. 

What you want to teach and what you CAN teach are very dependent on what students you have. If your aspirations don’t match your students’ aspirations, then conflict, misunderstanding, frustration, and failure are almost assured. Of course you are not doing anyone a service by watering down a course so it doesn’t serve the student’s needs. If students can’t for any reason handle the necessary material, they should find this out as soon as possible and change their career plans!

What do you want to teach?? How deeply??

Even after the most careful preparation, you should expect to make many modifications as the result of your experiences with the class, department, and school.

A. Why are the students taking the course?

    • What do they need to do with the knowledge they gain? Live a fuller life, vote intelligently, run an auto repair shop, pass a MSAT, go to graduate school in your discipline, etc.

B. What is the background of your students?

  • Right out of high school, still in high school, returning students, majors in your discipline, majors in auto shop. . .
  • Students who know something (i.e. have lived a little) are MUCH easier to teach than students straight from high school who carefully avoided actually learning anything!

C. What are their native languages?

    • Do they understand English? Spoken? Written? How well can they write?

D. Do they have the background necessary for your course?

  • Math? English skills? Maturity? Motivation? . . .

Macro Structure: Large scale structures for the course and lectures:

Tradition has it that the best teaching device is a log with a student on one end and the teacher on the other.

cartoon image of scoratesA. Socratic:

Perhaps the optimum method of instruction is one where the instruction is guided by the student’s responses. Obviously this will work best with one teacher per student or, someday, one computer per student. However, if you are lecturing, presumably you have more than one student. 

As done by Socrates, the teacher simply asks questions that guide the student’s thoughts and discovery.  Once the class gets into it, this method of presentation works well. It is fun for the class to be involved, and they will learn much better if they are thinking about the material. At first many classes are very resistant to actually thinking and responding, they have been trained to simply sit and regurgitate on tests. Patience from the teacher, rewards for trying (toss a Frisbee), and enthusiasm over efforts will eventually win over most classes.

If you can get responses from the entire class, you can guide the discussion so it will be profitable to most of the class. Simply asking the class to vote on a question by raising their hands is easy, visual, and fast. (e.g. how many feel this sentence is too long? How many feel it is too short? How many feel the length is about right?) You can then work out with the class which answer is correct or most reasonable. Often, very few or no students vote for the correct answer. The class generally finds this amusing, and they are comforted that they are not the only ones with the wrong answer.

There are machines that let each student answer electronically. This would seem to have both the advantage and disadvantage of anonymity. Students would not be intimated by having their choice revealed to the class, but they would not be engaged in the group activity of raising their hands. Giving micro quizzes should keep the students in attendance and awake.

B. Narrative (story telling, personal experience, anecdotes, humor):

People respond much better to experiences (stories) than to bare facts (e.g." I bankrupted my company because I signed a contract for a billion British dollars (a million million) when I thought it was a US billion (a thousand million)."  Students appreciate that you are also a person with good and bad experiences, not just a perfect lecture machine.  Much of what we still regard as wisdom from the past (Plato, Galileo, The Bible) is written in narrative or in the form of discussions between people.

Even what seems determined (as you plan it) to be a dry technical lecture can usually be enlightened by excursions into the lives of the people involved or the strange paths taken by those trying to find the correct answers. Real discovery is never straightforward but generally involves eliminating many blind alleys to eventually (one hopes) find the correct methods. A light discussion of some tries that didn’t work can help in appreciating the present understanding or lack of understanding. However, it is discouraging and time wasting to actually have to memorize all those obsolete theories. It is hard enough to learn the current best theories!

C. Historical

Often history provides a convenient framework to tie ideas together.  Keep in mind that (generally) the ideas are important, not the history itself!

Another caution is that our historical approach to science, may burden the students with many obsolete theories and incorrect observations. Analyzing past errors may be useful if they are used as cautions and bad examples (or to demonstrate that even fine analysis can go wrong). It is often said that no experiment is a complete waste; it can always be used as a bad example.  But, generally it is best to devote precious time and attention to current "best practices".

image of people jumping through hoopsD. Derivations (Relevance)

Mathematical texts in particular tend to be an endless series of "Theorem-Proof, Theorem-Proof, Theorem-Proof, . . " with little or no "human" text in between. This structure is certainly the fastest way to cover material, but it leaves the reader wondering why the material is being covered at all.

It is more humane and effective to first motivate the subject (i.e. what we would like to be able to do, and why we care) and only then go into the nuts and bolts of actually doing it.

The best teacher I ever had (Dr. White of USC teaching a senior course on the fundamentals of calculus) revolutionized my view of mathematics with this approach. He would explain what we would like to do (e.g. prove all functions could be integrated!). He would then raise objections one at a time and show how we had to put limits on our ambition and achieve a more limited (but achievable) end. When done, the student not only knew what could be done but why one wanted to do it and why there were limits on what could be done. Beautiful!

E. Observations >> Theory versus Theory >> Observations

"Believing is seeing"

1. Observations >> Theory

Some teachers prefer to start from experimental observations and deduce a theory that can predict these observations.

2. Theory >> Observations

Other teachers prefer to start with theory ("LAWS") and make predictions from these LAWS.  Both methods work at times and fail at times! Students and professionals differ considerably as to which method makes them comfortable, is quickest, and is most memorable.

It seems more natural to start with observations (preferable some observations familiar to the students) and develop a theory. If you are doing "science," you will then make predictions with your new theory and do experiments to see if nature agrees with your new predictions.  This procedure sounds like natural sciences, but is used in math too. 

Once LAWS have been deduced, it is generally more economical to use these laws to predict reality instead of memorizing all special cases. Not all students, or people, prefer this procedure. Many students simply want to know all the answers, presumably so they won’t be wrong or have to think. 

There can be considerable tension between the student’s expectations and the teacher’s expectations if the teacher insists that procedures be deduced from a few general principles rather than simply memorized. This process teaches students not just facts, it teaches then how to learn and how to think.

Micro Structure: Procedures and activities for good lectures:

"The power of instruction is seldom of much efficacy except in those happy dispositions where it is almost superfluous."

                                                    - Gibbon

A. "Tell, Tell, Tell."

The advice of the U.S. Army to teachers is "Tell them what you are going to tell them -- Tell them -- Tell them what you told them."

Good advice.  And, do not forget to review what you told them last time too.

people plugging a huge electrical outlet

B. Methods of presenting the material and involving the class

Here are many items you can keep in mind while developing your lectures. Some will keep your audience oriented; some will keep your audience awake!

Tell what you are going to "teach" today. This will help greatly in keeping the audience oriented. Listeners often have trouble separating the point of the lecture from the surroundings (i.e. they can’t tell the steak from the sizzle unless you help them).
Tell why the audience should care! Everyone pays more attention if they know the knowledge they are about to acquire will help their health or happiness (i.e. "Your chances of having cancer will be reduced by 30% if you follow these food guidelines").
What applications can you include? The more real world (or philosophical) applications you can reference, the more likely it is that the audience will identify with your point.
What are amusing parts? About grammar: "Piano for sale by lady with mahogany legs"
Is there some interesting history to the ideas?  
What questions can you ask the class to force them to actually use the concept? After outlining the classic plot of Romeo and Juliet, you can ask: "How many movies or plays do you know that are takeoffs on Shakespeare’s Romeo and Juliet."  Or, after defining "amplifiers" ask what political, social, mechanical, and religious mechanisms fit the definition of amplification.
Can you ask questions leading the class to discover the concept for themselves (Socratic method)? This works great for the students who participate. I suspect it doesn’t do much for the students who are waiting to be told "THE ANSWER".
Can you demonstrate the concept? With a demonstration, with the aid of the class, with slides, with movies, with videos, over the web...
Can students do part of the presentation? Generally student presentations are technically awful (but not always, some put professional teachers to shame), but they may more than make up with empathy what they lack in gloss.
Can you connect the concept to an overall theme of the lecture? Everyone learns items best that are connected in their mind. If the lecture has a theme to connect the parts, students may easily remember otherwise disconnected and arbitrary items. The theme doesn’t even have to be "correct", just mnemonic (e.g. taken alone, "Animal Farm" appears to be just a series of amusing and horrifying incidents. Taken as an analogy to the effect of Communism on a country, the outrages follow history and necessity like clockwork).
Can you connect the lecture to the overall theme of the course?  

C. Helpful activities and methods during class:

1. To encourage class participation:

  • Bring Frisbees to class and toss them to students who ask or answer questions. After class the students trade the Frisbees for points.
  • Do use soft Frisbees or nurf balls if possible! This plan not only rewards participation, but also keeps students awake dodging stray Frisbees.
  • Give the class an idea and immediately ask a question of the class that requires the use of the new idea. Tell about feedback and ask for examples in our body. Strangely a high percentage of most classes don’t even think about trying to answer the question.  They just wait for you to tell them the answer. You may have to be quite patient waiting for some brave soul to give a guess. If you can find some element of the answer to be enthusiastic about, the next try may come faster.
  • Give extra credit to the first student who reminds the class where you ended the previous lecture. Some classes fight to answer this, others look puzzled.
  • Ask the students what comes next during a lecture. This is quite natural during a derivation in math or physics. In any discipline this procedure should bring out the logical continuity of the subject.

2. Teacher’s activities:

Speak clearly and simply:

As Faraday, one of the great scientific lecturers of the nineteenth century, wrote in a note to himself:

  • "Never to repeat a phrase."
  • "Never to go back to amend."
  • "If at a loss for a word, not to 'ch-ch-ch' or 'eh-eh-eh' but to stop and wait for it. It soon comes, and the bad habits are broken, and fluency soon acquired."
Be enthusiastic!

The clues professionals (teachers, scientists, poets, . . .) use to recognize enthusiasm among themselves don’t mean much to students brought up on TV. These students expect much more noise and theatrical behavior than we consider professional. Loosen up!

  • History teachers can come in costume, use props, have backdrops, . . ..
  • Teachers can have impromptu dialogs with students acting out possible psychological scenarios . . .
Be funny

Humor: Once you try this, it is like shooting fish in a barrel. There is a considerable shock in hearing or seeing a dignified teacher joking. Don’t just say that an expression is not correct but write it on the board with a weepy (opposite of smiley) over it or an European road sign for NO (circle with a slashed line).

Using humorous mnemonics is always appreciated and useful.  Fortunately, or unfortunately, the less politically correct the mnemonic is, the more likely it is to be remembered, but be very careful, particularly at the beginning of the course.  A classic mnemonic is the one for remembering the resistor color code of BBROYGBVYW (the first letters of colors representing numbers e.g. Black, Brown, Red, Orange, . . .): "Bad Boys Rape Our Young Girls But Violet Yields Willingly."

Be Poetic

Electric charge leaks away with time in an exponential fashion: 

Miss Farad was pretty and sensual
And charged to a reckless potential;
But a rascal named Ohm
Conducted her home -
Her decline was, alas, exponential

Condensed Story of Ms Farad by A. P. French

Theoretical physicist has proved that protons will decay, but the protons don’t! Proton Decay
by David Halliday

A proton once said, "I'll fulfill
My long-term belief in free will.
Though theorists (may) say
That I ought to decay
I'm damned if I think that I will."

In the unlikely event that you want more physics limericks here is the URL: http://www.aps.org/apsnews/11855.html

Explain (in English!) Exotic words are easier to remember if the etymology is explained.  For example, a positron (a positively charged anti matter electron) is "posi because it is positively charged, tron to sound scientific."
Bring Friends Students love to have guest speakers. Possibilities include: leaning on a friend to give a guest lecture, trading guest lectures on your specialties with another teacher, assigning a lecture on campus to replace your class . . .
Use what the students already know Build on the students’ knowledge: We often learn best when we appreciate that some new knowledge can be understood as an new way of looking at something we already know. Some people feel that this is the only way to "learn".

Explain that electrical current is like the current in a river, electrical voltage is like the speed or the river, a battery is like a water pump, . . . Do be sure that the students have actually heard of the item you are using for an analogy. I find that Southern Californian students have only a very dim idea of a river.

Get Close to the Students, and vice versa Walk around and get as close to the class as possible, much more friendly.

Have the students hiding in the rafters move down near you. The students will pay much more attention, they will talk less, and the class will feel much more like a group rather than isolated individuals.

Show that your subject is alive and not just in old books designed to make students miserable. Bounce into class often with news of today’s developments or discoveries in your field. This may be a stretch if you are teaching Elizabethan Literature, but I am sure something will occur to you!

Even better, give extra credit to students who can orally report to the class about things that have developed in your field within the last week. 

Require or give extra credit for bringing in news articles on current activities in your field. TV and Internet are also good sources.

Require or give extra credit for doing research reports on current activities in your field using only magazines published in the last six months. Requiring recent magazines seems to almost completely eliminate old papers or papers from pay sources. I was very suspicious when I recently got several papers using many of the same articles. I found that the students were simply using the same search engine at our library!

Give extra credit for showing you web sites (new to you) devoted to your discipline.


3. Student presentations:

  • Give extra credit or require students to present a topic to the class. Showing how an experiment works or how physics applies to electric guitars (for example) works well. Classes really appreciate such presentations.
  • Have students do a short reenactment of history, psychology, . . .

4. Learn by doing

Many believe that almost all learning is done through physical experience. Generally the more the students can experience the subject, the more likely they are to remember and incorporate the lesson into their worldview.

For about a century, labs have been a standard part of the physical sciences. The design and procedures of teaching in formal labs is a subject of another Dig Deeeper section ("Labs"), but short hands-on activities can be incorporated into lectures too. Political Science classes can take straw votes (even trying out various methods to resolve "non-majority" elections), psychology classes can try analyzing the teacher, . . .


To keep the audience awake and interested, the more color, motion, and sound the better.

Lectures are much more pleasant if they do not just consist of a "talking body". Teaching aids can help the class follow what you are doing, keep the class awake, and demonstrate things the students have never imagined.

Lecture Demonstrations

Read Faraday’s "The Natural History of a Candle" for the example of a masterful use of lecture demonstrations.

Demonstrations are remembered and beloved by students. To demonstrate before students very eyes that their ideas are mistaken would seem to be the height of effective teaching. To show students a phenomena that they could never have conceived would arouse the wonder of even the most blasť student.

My students regularly ask for demonstrations, write enthusiastically about these experiments, and complain when there are no experiments. However, strangely, when tested on the point of the demonstrations, students seldom remember what the point was! (Of course this may simply reflect on the quality of my demonstrations.) Still, if the goal of lecturing is to generate enthusiasm for the subject, these "failed" demonstrations were really successes.  A few suggestions:

  • Make it spectacular!
  • Make it BIG!
  • Make it simple.
  • Tell, Show, Tell.

Tell the audience what they are going to see (unless you want to mislead them for a more surprising effect). Show them the demonstration. Tell them what they just saw. (Or ask them what they just saw and whether it matched what you promised and/or what they expected.) 

Don't forget to Practice, Practice, Practice:  A demonstration is a show and must be done with some showmanship. You can’t be slick and confident if you have to worry about the demonstration working or about remembering your patter.

  Microphones and Speakers

Use a wireless mike whenever possible.  There is a tradition that a "real teacher" doesn’t need a mike. NOT TRUE. 

It is much more relaxing for students to be able to easily understand the teacher rather than to have to strain to interpret every word. It is much easier to take notes if every word is clear.  From the teacher’s standpoint, it is hard to sound friendly when almost shouting!  If the teacher is describing what they are writing on the board (a great help for note taking) the explanation will be much more effective with the aid of a mike and speakers.

Note:  If you have a health problem such as asthma that makes a microphone a necessity, be sure to inform your department chair, dean or other campus official responsible for equipment that you will need a microphone on a regular basis.

Chalk boards, and / or white boards:

These are venerable, but still the tool of choice for some purposes. The good points are that the class actually sees the development as you write it and your results remain in view until you need to erase the board. Some thoughts:

Black or white boards are much preferable to colored boards; your writing or drawing will show up much better

  • Write darkly; soft, fat chalk helps.
  • Don’t block the students’ view of what you are writing. This takes practice.
  • Write BIG.
  • If not done to excess it helps students take notes if you describe out loud what you are writing as you write. Do remember to turn around when you are not writing!
  • Clear writing is even better than spelling!
  • Practice so the finished boards will be in a logical order, not the usual student’s shotgun blast of words and formulas.
  • If there is a lot of detail, tables say, it is best to confine the chalkboard to the big picture and have a printed handout of the details.
  • Beware: Students religiously copy what you put on the board and ignore your explanation of what it is all about.
  • Watch the class. Do they have time to take notes? It is helpful to stop and let the class catch up. This is something movies can’t judge!
  • Erasers: If you must erase much, get some big, soft cloth erasers, not those standard skimpy black erasers.
Overhead Projectors
  • Keep it simple and slow. It takes much longer to understand plots, tables, etc. than it does to flash them on the screen. Take your time and walk the audience through the picture.
  • Color will help wake up the class
Slides Slides are a great combination of color, detail, and personal input into the lecture (if you took or are associated with the slides). The downside is the time involved in taking, organizing, and presenting the slides.
Pictures from computers with a digital projector If computers and projection equipment are available on your campus, they can replace overhead projectors and slides.  Be sure you are VERY comfortable with the computer and can manage basic technical problems before using it in class.  It is great to click a few times and show anything from the Taj Mahal to one of Jupiter’s moons.

Videos, taken in moderation, generally provide lots of action. Educational video and movies have a surprising problem of "information overload." The facts come so fast that the student drowns in information.

It helps a lot to go over the vital points before the video, show the video, and then discuss the video. Really outstanding presentations (e.g. "Powers of Ten") deserve a rerun with pauses to discuss the outstanding or puzzling points. I generally promise a short quiz the meeting after any "sound and light show." Just a question such as "What was the most surprising thing you learned about astronomy from the video?" will work well. This is easy to grade and encourages attendance and alertness.

Presentation software for computers:

Logically, since computer presentation software (e.g. Power Point) is designed to convince and educate, I’d expect it to be taking over lecturing. However few teachers as yet seem to use this software. Perhaps related to the low usage is the low instructional value of most presentations that I have seen. Still, there seems an enormous opportunity there when we learn to exploit it.

When developing presentations (e.g. Power Point), I’d advise avoiding animated and colored lists, which can easily be replaced by printed handouts. And I would advise exploiting what these programs can do that is hard to do by hand: pictures demonstrating the point, movie clips, sound associated with the point etc.

These presentations can be easily (at least in theory) exported to the web. If you do have useful and/or fun presentations, you might want to put them on your web site so your students can run them whenever they want.

Classroom Management

A. Classes differ

It is a real help to have several classes on the same subject at the same time.  Each class has a different character. Some will just sit there waiting for permission to leave. Others will ask so many interesting questions that it is hard to get through your material.

When you have a class of the second type, it is obvious what a great teacher you are. If you have a mix of classes you can blame any problems on the students in the dull class.  However, if you only have one class, and it is a non-responding type, it is all too easy to feel that the problems are all your fault. Of course you must keep in mind that the problems indeed may be all your fault, and that it would be a good idea to change your ways.

However, before changing your career path, consider that it may just be a dull class. Taking these problems as an opportunity, you can try more and more outlandish things to see if the class will respond to anything at all.

B. Seating

  • To encourage class cohesion:  Surprisingly, seating can make a considerable difference in how lectures go. The closer the students get to you, the better the tone of the class will be. Students close to you and each other tend to feel part of a group, students seated far to the rear don’t generally get involved emotionally or physically in the class. Usually you can simply ask that no one sit in the last four rows, and after a meeting or two most of the class will get the idea.
  • For test taking: discussed with cheating
  • For taking roll: discussed with "taking roll"

C. Taking roll

Taking roll is often necessary for bookkeeping purposes or to encourage attendance. Often roll taking is time consuming and disruptive. Some possibilities are:

  • Pass around a roll sheet for students to sign or initial. This is not too disruptive and will satisfy accounting requirements. Students will liberally sign friend’s names so this is only so-so for encouraging attendance.
  • Post a sign up sheet, much the same pros and cons.
  • Have students swipe their student ID cards if these cards have magnetic stripes. This sounds appealing!
  • Have a seating chart and mark the empty seats.  This can get hard if you have a small, scattered class in a large room.
  • Have a seating chart and arrange for the students to be densely packed, revise this during the semester to eliminate empty seats. This seems like it would work, but the student’s may well feel over managed!

cartoon image of man scared in bed with flames at side

D. Nightmares

1. Example from the top:

Then Jesus took his disciples up the mountain and gathered them around him; he taught them saying:

Blessed are the poor in spirit, for theirs is the Kingdom of Heaven,
Blessed are the meek,
Blessed are the merciful,
Blessed are they that thirst for justice,
Blessed are you when persecuted,
Blessed are you when you suffer,
Be glad and rejoice for your reward is great in Heaven.


Then Simon Peter said, "Are we supposed to know this?"

And Andrew said, "Do we have to write this down?"

And James said, "Will we have a test on this?"

And Philip said, "I don’t have any paper."

And Bartholomew said, "Do we have to turn this in?"

And John said, "The other disciples didn’t have to learn this."

And Matthew said, "May I go to the bathroom?"

And Judas said, "What does this have to do with real life?"

Then one of the Pharisees who was present asked to see Jesus’ lesson plan and inquired of Jesus, "Where are your anticipatory set and your objectives in the cognitive domain?" 

And Jesus wept.

2. Late students, and early leavers:

In many cases, students arriving late disrupt the flow of a class and may make it impossible for the class to hear what the teacher is saying. My experience is that some people are simply programmed to be late; they won’t change so it is up to the teacher to deal with the problem. Some attacks on the problem are presented below, arranged in order of increasing severity.

The happiest solution would be to give such striking lectures that no one would voluntarily miss a second of the show. If you can do that you don’t need my advice.

You can gently discuss with the class that you realize that everyone occasionally must be late (broken leg climbing the stairs to class) and explain how they can enter the room causing the least disturbance: enter at the rear if there is a rear entrance, walk quietly, sit in the rear, don’t ask friends what is going on, have necessary papers out of their pack BEFORE entering the room, etc.

  • Put a sign outside (blocking perhaps) the entrance reminding students of the rules for latecomers.
  • Give snap quizzes occasionally at the start of class. This has the additional benefit of encouraging students to study for every meeting. Unfortunately many students have been programmed to never study unless a test has been announced!
  • Take roll at the start of class and penalize late students. (How to do this efficiently in a large class leads to several ingenious plans.)
  • A downside to early tests or roll is that the message to some students is that the important part of class is over after the roll or quiz and that they should leave. In some cases I have worried about students being crushed in the rush to the door.
  • You can escalate this warfare by taking roll or giving quizzes at the end of class.
  • I’m inclined to feel that class should be an open, friendly experience, one that proveds a collegial experience, not a prison-like experience. It may be more profitable not to worry much about the escapees and realize that their absence increases the average enthusiasm of the class. In any case, students who miss much of class will eventually eliminate themselves on tests.
  • Lock the door(s) for the first fifteen minutes of class, do the locking "on the dot" of the time class is scheduled to start. After fifteen minutes open the doors and let the stragglers in. This works surprisingly well: there is one interruption instead of many, it is obvious to students who arrive late that there is a problem, and everyone is reminded daily that coming late is not a good idea. Of course this can be easily combined with early roll or snap quizzes. Students seem to take this procedure quite for granted.

3. Talking

Excitedly talking about the great new ideas you have just presented can be taken as a sign of success; but most talking is about who to date over the weekend. Ignoring talking is not a good plan. A background murmur makes it hard for other students to hear and participate. Furthermore, background talking sends the message that the lecture or discussion isn’t really important.

Your problem is to eliminate the talking without interfering with the flow of the presentation and without permanently offending or scaring anyone. Some possibilities are:

    • Ask politely and enthusiastically if you can help with their problem.
    • Explain why talking during class is not polite.
    • Ask the talkers to answer your last question to the class or a question you make up for their benefit.
    • Take points off for talking.

4. Over Argumentative

If you are confident about your presentation, disagreement from the audience is to be welcomed. On the one hand you can point out the misconception that led to the student’s error. Or, even better, you can acknowledge that there are other possibilities than the ones you were discussing and explain why you chose the one you did.

However, occasionally the student will not take any reasonable answer and will keep insisting, perhaps with floods of "facts" that you are wrong. This is annoying and time consuming, and, of course you could be wrong. Some things you can do:

  • Say that this point is interesting, that there isn’t time to go into it now, but you would like to talk to the student after class.
  • Say the point is interesting and perhaps the student would like to write an extra credit report on the subject.
  • If the point is interesting and one on which other students may have opinions, you can ask the class for their comments.
  • Say that this is interesting and you would like to look into it and report back to the class next meeting.
  • Give a counter example (e.g. all odd numbers are not prime. Despite the promising examples of 1, 3, 5, 7. Nine is divisible by three!).
  • Unfortunately a really dedicated heckler will not be detoured by mere facts. However the rest of the class may be impressed.

"That’s unfair"

This is heard most often after you grade the test the way you said you would (e.g. Your test says at the top that only complete sentences will be counted, you announced this when you announced the test, you announced this when you handed out the test, your syllabus states this in capitals and bold face, you spent half a class period explaining the vital impact good grammar would have on the student’s career prospects). However "It’s not fair!!"

What to do?

  • You can (and will be strongly tempted to) explain that life is not "fair" but to survive one must simply do things the way your boss, teacher, computer, or nature wants.
  • You can patently go over the rules. This generally doesn’t impress a really annoyed student.
  • You can ask the class what the rules are, and why. This works pretty well. Almost always someone will remember the rules and why the rules are the way they are. It is difficult for the irritated student to argue with the whole class.
  • Ask for an improvement to the rules for next time. Occasionally you will get a real improvement, and your teaching will improve!

5. Questions you feel you should be able to answer but can’t

This situation is often a nightmare for new teachers; it certainly was for me. Fortunately there are several fine solutions. All honest solutions start with a loud, clear "I don’t know!" This will often get you a sympathetic laugh and get the class on your side. You can then say:

  • "I’ll look it up or figure it out and report next time." This gives you time to do thorough research, consultation, experiment, calculate, etc. You can then give a exceptional explanation the next time.
  • "That will make an interesting extra credit problem for next time." Now both you and the students can research etc.
  • "I’ve always wondered about that, but never could figure it out. I’ll think some more about it." This may be hard to carry off in a math class, but is all too common in Quantum Mechanics and Relativity. I often then go to my favorite "tell it like it is" source (The Feynman Lectures on Physics) and sometimes get an explanation and sometimes get the comforting advice that "There doesn’t seem to be any reason, but it works."
  • "Tradition"

6. Questions about sticky points in your subject

Honesty works great here, too. Some possibilities of turning confusion or dispute to your favor:

  • " Darwin said ..., but I never could believe that." Of course substitute whatever authority is appropriate in your discipline. This gives a great entry into how opinions are developed in your field. The fact that human knowledge was not found on stone tablets (well, most of human knowledge) but has gradually evolved over the eons is a vital observation that cannot be demonstrated enough.
  • "Here are some current opinions and my estimate of how much to trust them." Another chance to demonstrate that your field is still developing.
  • "Now that is a real problem!!" Astrophysicists can’t find ninety to ninety-nine percent of the mass in the universe (circa 2001). Embarrassing situations like this should be taken as an opportunity, not as a problem. There is not much chance for earning fame and fortune in a field where everything is known.

7. You forget a vital step in your analysis or derivation or your results come out backward


After panicking, step back, take a few deep breaths, and stare at the problem (if it is written). The object is to give yourself some time to consider what went wrong. Before it was politically incorrect, professors would take out a pipe and go through the lengthy procedure of filling and trying to light it. A great deal of professorial dignity has left with pipes. If inspiration doesn’t come fairly quickly (it will seem like hours in any case) you can consult your notes, if you think it is in your notes, or perhaps the book. In the nature of things though, you will not have the correct notes and the book will finesse around the point.

Honesty is a great help now. Tell the class your problem. If possible, explain why you know the present result is impossible.

Usually (always, in my experience) the class will be quite interested. You can ask the class for help. Now you and the class are working together, great! You will usually get several wildly wrong suggestions. This is distracting, but you want to play for time. Thank the students and point out gently the problems with the suggestions, commenting on any good points, or complementing the student on their bravery if there are no other good points. If you are lucky, some clever student will point out the correct step, and you can proceed.

If neither you nor the class can figure it out, don’t waste too much time on it. Promise to explain correctly next time and, if possible, proceed with the analysis. My classes always seem friendlier after such an episode than if things go perfectly.

8. You never could understand this argument

When I was a student I, of course, felt it was my fault that I didn’t understand many parts of physics. When I began teaching and had more time and textbooks to consult, I often found that the books all copied the same lame explanations from each other. Evidently none of the authors understood the point. Now, what can you do when it is your turn to explain this tricky point?

A classic method of finessing the problem is to arrange for the subject to come at the very end of the semester. You then "find" there is not enough time to cover that point, but promise that it will be covered the next semester. If you are teaching "the next semester" you simply start the class announcing "as you learned last semester . . .".

If your morals won’t let you adopt this plan, the best procedure is probably to tell the class that this is a tricky point, give the best analysis you can, and explain that you don’t much trust this analysis either. You can offer extra credit (lots) for any student that can produce a convincing analysis, by any means.

It is also wise to consult your friends in the discipline. They may have a brilliant suggestion, or reassure you that they too are challenged.

Best wishes for a terrific class.


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