Video lectures

Video lectures vs live lectures
Advantages
* You can watch them anytime you want (e.g. when you are most alert)
* You can watch them pretty much anywhere you want (e.g. on the bus on your smartphone)
* You can pause and repeat part of the lectures.
* You can watch all or some the lectures again and again (e.g. while doing a homework problem or  preparing for an exam).
* Good video lectures are short (max 7-10 minutes) and focussed on one specific topic.
* As a teacher you can't "get behind" on your lecturing.
* Video lectures free up valuable class time for discussion, e.g. using peer instruction.

Disadvantages
* Students cannot ask questions right away.
- In most large courses this is practically impossible anyway.
- In my experience questions occur very infrequently, even in smaller courses.

* If you use your lectures to inspire and motivate students that is probably better done live
- While students enjoy such lectures, there is no evidence that they learn more from them than "boring" lectures.

* Students won't watch the videos
- I really recommend "reading" quizzes
- Students also skip your live lectures.

Video lectures vs assigned reading
* If your lectures (or some of them) are basically repetition of the textbook, just assigning the reading instead of making the video lectures. Make sure they read it using "reading" quizzes

* Another alternative to making videos are detailed lecture notes, if you have them already.  If you don't, making video lectures is much faster than writing detailed lecture notes.

Powerpoint vs chalk-board (pen-cast) lectures
For live lecturing students tend to favor chalk-board lectures over Powerpoint lectures, because the pace of chalk-board lectures tends to match that of note-taking.  The relatively slower pace of chalk-board lecturing also means that fewer new concepts are introduced during lecture.

In the case of video lectures these differences largely disappear.  Students can pause and repeat Powerpoint video lectures. Pen-cast lectures (the video equivalent of chalk-board lectures) are no longer restrained by the available lecture time and can cover just as much as Powerpoint lectures.

It it telling that it is possible to view Powerpoint video lectures on the on-line platform Coursera at 1.5 or 2 times the regular speed. There seems to be no demand for slowing the Powerpoint lectures down!

I tend to make Powerpoint video lectures rather than pen-casts because I often present rather complicated equations or diagrams that are laborious to write or sketch by hand. However, if I want to demonstrate some thought process (e.g. solving a problem) then I use pen-casts.

In any case, I always give students access to the Powerpoint slides or the handwritten notes I base the video on. It is much faster to read these notes than to watch the video. If the written material is clear, there is no need to view the video.

Good video lectures
* The optimal length is about 7 minutes
* One specific topic per video
* At least one multiple choice question per video
* Students can handle no more than 7 such videos (new topics) per lecture period.

You can see some examples video lectures that I made here.

Making the videos
Here is how I make Powerpoint video lectures and pen-casting video lectures.

This post is part of an ongoing series of post on teaching tools and tips collected here.

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Peer instruction briefly explained

Peer instruction is an alternative to the traditional lecture an was invented by physics professor Eric Mazur at Harvard.  You can read about how I use peer instruction here.

The "mechanics" of peer instruction is very simple:

1. Pose a (multiple choice) question to the class.  

2.* The students vote on the answer using clickers or e-clickers.  I use Socrative.  Mazur advocates that students not be allowed to discuss before the first vote. I encourage students to discuss right away.

3. If the majority (roughly >75%) vote correctly, briefly explain the correct answer and move on to the next question

4. If 40-75% vote correctly, ask the student to find someone who has voted different than themselves and convince them that their right, then revote.

5. Of <40% answer the question correctly, give a detailed explanation of the problem and solution.

The advantages of peer instruction

* The students are doing something actively rather than sitting passively

* They have an easier time learning from their peers who are at the same "level"

* Good peer instruction questions focus on conceptual understanding, which is rarely addressed in homework

* The teacher gets valuable feedback on what the students know and don't know

This post is part of an ongoing series of post on teaching tools and tips collected here.

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Reading quizzes

A basic tenet of the flipped classroom approach is that students come prepared to class and I have found "reading" quizzes good way to help ensure that. (Here I put reading in quotation marks since it can also refer to video lectures.) Put another (stronger) way, I would not attempt any kind of flipped classroom activity without assigning reading quizzes.

I use the quiz function in Absalon, which is the course management system that the University of Copenhagen uses, but I am sure most of what I discuss below can be done with other course management systems such as Blackboard of Moodle.

Some general considerations
* My reading quizzes are usually 5-10 questions covering reading/video material they familiarize themselves with before we meet.  If you require more questions to cover the assigned reading/video then you are assigning too much.

* The quiz has two purposes: 1) to encourage students do the reading/watch the videos and 2) to let them know whether they have watched them with sufficient attention

* The quizzes do no contribute to the grade, which allows me to give immediate feedback on the answer.  This is really important as it turns the quiz into a learning tool.

* I allow (and ask) them to keep answering until they get all the questions right

* Absalon allows me to label the the quiz as "mandatory", though the repercussions for not taking it is left vague.

* The quizzes are not meant to be extra homework.  The questions are easy to answer if you have read the material.  I often use true/false questions.

* The last question is always "Did you find anything confusing that you would like explained when we meet?"

* I set the deadline for the quiz at midnight the night before we meet. There is good evidence that sleep is important for the transfer of knowledge from short- to long-term memory.

* Absalon has a nice feature where I can selectively send email to students who haven't taken the quiz yet.  If I remember, I do this around 8 pm.

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Peer instruction: writing good (chemistry) questions

A good peer instruction question is a question that facilitates a good discussion and is just difficult enough that about half the students get it wrong on the first vote. Such questions are hard to write. Be prepared to spend time and mental effort on this, and to revise or replace questions in coming years as you get feedback from the students.

If you ask bad questions students will grow bored quickly. Avoid simple recall questions (the particles orbiting the atomic nucleus are called ...?), questions that can be answered by a simple Google query, or questions that require a calculator (how many moles in 32 g of Bi?), none of which facilitates discussion.

Below I collected some example of questions I have used in my thermodynamics class:

Different kinds of peer instruction questions for thermodynamics from molmodbasics

I always include a "don't know" option and tell them: "if you really have no idea how to attack the problem, don't guess; let me know by voting "don't know".

Also, don't over-define the problem. It's OK to leave things out (such as underlying assumptions or simplifications) and let them ask you as needed.

Slide 1. This is a typical multiple choice question where the students are presented with several answers that are quite different from one another. These are hard to write because it is difficult to come up with several different but plausible answers (see also slide 6).

I use this question to address two common mistakes I have seen my students make: A looks good because they confuse the entropy of the universe (which goes to a maximum according to the second law) with the entropy of the system. C looks good because students confuse the standard free energy change with the free energy of the system.  I also use graphs and pictures whenever possible.

Slide 2. A better approach is often to formulate questions such that the possible answers are "more", "less" or "the same" (or "increase", "decrease", "stay unchanged").  This is probably the most used peer instruction question format.  The challenge then is to formulate the question such that one of the wrong answers looks most plausible.  Here the two complexes look very similar so option C is somewhat attractive.

Slide 3. Another variant of more/less/the same

Slide 4. Another approach is to ask which X has the largest/smallest value of Y. Here it is important that the choices are sufficiently different so that the answer can be obtained without looking anything up or memorizing it. In this case each molecule has a different number of polar atoms. The question can also be rewritten as a ranking problem, such as that shown in the next slide.

Slide 5. Ranking in order of increasing/decreasing X. I use molecular models rather than chemical formulas so that they have to deduce the molecular charge themselves and get a sense of the relative size of the molecules; both if which are key to answering the question correctly.

Slide 6. This is an example of how to cover equations without asking questions that require a calculator.  Also, since it harder to formulate plausible wrong questions I ask for the answer that is not correct.

Slide 7. This question appears to break the "calculator rule".  However, I have taught them how to estimate the result to within an order of magnitude and formulated the question accordingly.  I use this approach only for the 1-2 most important equations covered in the course and I ask about it frequently - it is a difficult skill to learn.

Experiments and Simulations
The above type of questions can be greatly improved by including (movies of) experiments or simulations. It makes the topic less abstract and more relevant and it addresses exactly what chemistry is all about: explaining observations in terms of the behavior of atoms and molecules.

I typically search Youtube for "xxx experiment" or "xxx simulation" and then capture the part of the video I want with screencasting software such as Screenflow or Camtasia and insert the resulting movie in a Powerpoint slide. The free program Molecular Workbench also has en extensive library of simulations and allows you to make your own.  Of course you can perform the experiment in class or record your own experiments in lab.

Here is a video of some of the questions I have made for my thermodynamics course


Short Answers
Socrative has a nice feature where you can ask an open question, collect answers, and send them out for votes. For undergraduate courses I usually use this option at most once in a 45 minute period (and multiple choice for the rest) because I have found that using it more than that simply exhausts the students.  I think it is because they have a hard time formulating a written response on topics such as thermodynamics that they still find very abstract. For graduate courses I use short answer almost exclusively. Here are some short answer questions I have used in my thermodynamics course

Short answer questions on thermodynamics from molmodbasics

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Dear MONA: a chemistry professor reads a pedagogy article

MONA - Matematik- og Naturfagsdidaktik is a Danish journal for research in STEM education and their editorial office asked me to comment on an (paywalled) article on the use of clicker in STEM education at the University of Southern Denmark. Sort of a post-publication peer review, which is a nice idea.  This blogpost is a draft.

My background so you know where I am coming from
I have taught chemistry courses since 1996 both in the USA and in Denmark. I used the standard lecture model (always blackboard, never powerpoint) until about 3 years ago when I switched to peer instruction.  I use the Socrative.com site where students vote using their smartphones or laptops.

The study and the course
The paper presents an analysis of a questionnaire on the use of clickers given to students in a first-year biology course that must be taken by most science majors at the University of Southern Denmark. The enrollment was 290, 184 took the exam, and 58 filled out the questionnaire.  In addition, the paper presents quotes from 4 interviews with 10 students in their first (6), third (1), and fifth year (3).  I don't think all these student where enrolled in the course.

The instruction consisted typically of a 2 x 45 min lecture with 3-4 peer instruction questions in total. The questions focussed on either recall of facts or testing of conceptual understanding (more on this below). There was usually one round of voting with discussion before the vote.

Some observations on the study
The study states "... good teachers can improve their teaching with clickers while bad teachers don't necessarily improve their teaching just by using clickers." I think that is very true, so it is worth keeping in mind that the questionnaire offers feedback on one particular teacher and one particular way of using clickers in one particular course. More on this below.

Related to this point: in my experience it is often the "good" lecturers who are most resistant to trying clicker questions and other actively learning techniques. This is unfortunate because there is not data to indicate that students learn more from engaging lectures - they are just less bored.  As Richard Feynman wrote in the preface to his famous lecture notes:

I don't think I did very well by the students. When I look at the way the majority of the students handled the problems on the examinations, I think that the system is a failure. ... It's impossible to learn very much by simply sitting in a lecture, or even by simply doing problems that are assigned.

The course is still mostly lecturing.  The interviewees mention that one of the advantages of clicker questions is  "People who are half asleep wake up and participate and everyone in the classroom is talking."  To me that begs the question why put them to sleep in the first place?  The "traditional" peer instruction/clicker approach is that the students prepare at home and then the entire "lecture" period is used for questions.  This is what I do.

The interviewees mention that "the clicker questions ... should test understanding and not recollection of facts and be of such difficulty that the individual student will submit both wrong and right answers."  So I was a little disheartened to read that the clicker questions included recollection of facts.  In fact the question highlighted in the article (see below) as a conceptual understanding questions is actually a factual recall question that you can answer in, literally, 15 seconds using Google.

The goal in writing peer instruction questions is to write questions that ca half the students answer incorrectly on the first vote, followed by a discussion and a second vote because this leads to the best discussion and ensures that the majority of students are challenged. So I was a little disheartened to read that the students only vote once on most questions.  The article states that on average 59.7% voted correctly on the questions, so it looks as though students would have benefitted from more discussion with each other.

I was happy to see that only 60% liked to see the result of the votes.  I never show the results of the vote. If the vote is nearly unanimous then showing the vote results is uninformative and takes time. If the vote is split than the results bias the revote.

I would very much have liked to see a question related to the pacing included in the questionnaire. The biggest critique I go when I first started using peer instruction was that the whole process was too slow.  Now my advice is better too fast than too slow.

Were the article not behind a paywall and written in Danish you would now point out to me that despite all my reservations of the way clicker questions are used in the course the study showed that the 98% of the students think clicker questions should be used in the course in future years. I would argue that after 20-30 minutes the students would welcome almost any break from being lectured to - the teacher's cell phone ringing or a knock on the door by a lost visitor - and, if asked, would enthusiastically recommend that the practice be continued.

The big question?
The study ends with, but does directly address, the "big question": do students learn more? This question is often re-phrased as "do more students pass the course" and a recent meta study indicates that introduction of active learning techniques can decrease the failure rate from 33.8% to 21.8% in STEM courses.  While this is a great way to sell the approach it is worth recalling why peer instruction was invented to begin with.

In the early 1980's - the good old days of lecturing before students could check Facebook on their cell phones - an astute physics professor developed a set of very simple conceptual questions related to the classical physics of force (the so-called Force Concept Inventory). Careful studies involving thousands of students at several different universities showed that passing a first year physics course did very little to improved these students' very poor conceptual understanding of basic Newtonian mechanics.  This was also true to courses taught by brilliant award winning lecturers.

When physics professor Eric Mazur read about this study in he late 1980's his first thought was "not my students" - motivated Harvard pre-med students who did consistently well on his exams and gave his lectures rave reviews. But as he discovered his students conceptual understanding was equally poor and their ability to solve relatively complex physics problems on the exam was a result of memorization. As a result Mazur invented the peer instruction approach where the "lecture" period was reserved to focus on the conceptual understanding, which is hard to address with homework problems - not to improve test scores.

This is why it is so important to ask good conceptual clicker questions: it is the only time they develop and are tested on their conceptual understanding of the subject. If the clicker questions are merely recall questions or mini homework problems the underlying problem (rote memorization leading to superficial understanding that is quickly forgotten) are not addressed even for the majority of the students who pass the course.

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A look inside one of my flipped chemistry classroom

Here is the approach I take in my second year thermodynamics course.

The "lecture"
* I meet with the students twice a week for 90 minutes (plus a 15 min break in the middle).

* The very first time we meet, I lecture for 5-10 minutes, then ask a question on which we vote using Socrative, and repeat.

* Before every meeting after that the students must watch 4-6 video lectures, each 5-10 minutes long. Each video concludes with a multiple choice question with answer, i.e. immediate feedback.

* The videos are based on Powerpoint slides that the students have access to while they watch the video.

* Before every meeting after that the students must answer a multiple choice quiz with a question for each video.  The questions are relatively easy to answer (often T/F) for someone who has watched the video.  The students get immediate feedback on the answer to each question.

* The deadline for the quiz is midnight before the meeting.  The quiz is mandatory, though the repercussions for not taking it is left vague.  The U. Copenhagen course site has a nice feature where I can selectively send email to students who haven't taken the quiz yet.  If I remember, I do this around 8 pm. The quizzes do no contribute to the grade, which allows me to give immediate feedback.

* During the our meetings I use the peer instruction approach, where I ask about 10 multiple choice and 2 short answer questions using Socrative.  Roughly half the questions cover material from previous weeks and new material, respectively.  The questions tend to be conceptual questions that facilitate discussion.

* The students get the Powerpoint slides with the questions (but not the answers) after our meeting.

* The Powerpoint slides and videos replace the textbook for the course.

The homework
* Teams of up to 30 students meets with a TA for a 4 hour session every week where they can get help with the homework.  If possible I show up for an hour or so for each session to get a feel what students are struggling with.  How else will you know?

* Each week I present them with about 10 homework problems, of which they have to solve a minimum of about six. The first six are relatively easy and should be doable by everyone who deserves to pass.  The last four are more challenging and one of them is typically an open ended question. The mere fact that the student chose a particular problem makes them invested in solving the problem.  In my experience most students attempt all 10.

* The answer to the question is provided as multiple choice using the PeerWise platform, i.e. the student is presented with 4 possible (often numerical) answers, where one is the correct one.  After the student chooses one answer they are presented with a detailed explanation of how the problem should be solved.  In some cases this takes the form of a video, but most often the solution was a screenshot from MAPLE.

* The homework does not contribute to the grade (which allows be to give immediate feedback). However, PeerWise uses points and badges as motivators, and I frequently highlight the number and kinds of earned badges on the course website.

How I designed the curriculum 
1. I started by writing the homework problems I really wanted them to be able to solve. They are encouraged to use MAPLE, so the problems can be quite mathematically involved.  Ideally they involve some application, experimental data, or simulation.  You can see them here.

2. Then I wrote the in-class questions related to the underlying concepts behind the homework problems. I also included some questions on estimating answers to questions that where similar to the homework questions.

3. Next I created the Powerpoint slides for the videos, containing the information they would need to do the homework.

4. Then I recorded the videos.

5. Finally, I wrote the quizzes.

Contrast this to the usual curriculum "design":

1. Find a textbook and select relevant chapters

2. Divide "number of chapters" by "number of lectures" to obtain content of each lecture

3. Hunt through problems in the back of chapters for homework problems, most of which are uninteresting "toy" problems written to illustrative some concept from the chapter.

Considerations that went in to the curriculum design
* "Relevance" is a great motivator. Write relevant homework problems and let them drive the curriculum. If something doesn't contribute to solving an problem, leave it out.

* Just in time instead of just in case.  Introduce new concepts and technique as you need them to solve a problem. "You'll need this for later" is not a good motivator in and of itself.  For example, spending a lot of time deriving an equation before you know how to use it is not very motivating.

* Cognitive load. You can handle no more than 7 new concepts at a time.  So, one new concept per video and no more than seven videos before each meeting. Yes, you'll have to reduce your curriculum to avoid drowning out the important stuff.

* Spaced learning. Things don't "stick" (committed to long term memory) until you have seen it 3-4 times over a period of weeks. Covering something once or repeating something several times in the same lecture doesn't work. This means you have to start the course with the most important concepts to you can repeat the most important stuff most often.  Yes, you'll have to reduce your curriculum since you have to cover many concept several times.

source

Considerations that went in to the choice of teaching style
* Active learning. Ultimately, you are teaching students skills not facts.  You only learn skills my actively doing something.  As you apply the skills often enough you will commit the relevant facts to long-term memory.

* Peer instruction.  Students have an easier time understanding explanations given by their peers than by you and students learn an awful lot by actively explaining things to their peers.

* Formative assessment. Answering questions is a powerful learning techniques if you get immediate feedback. Problem solving and conceptual understanding are two different skills and both must be assessed.



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Using Socrative in university courses: practical aspects

What is Socrative?
Socrative is a free student response system (or "web-clicker") that allows you to collect answers from students using the web.  I use it in all my courses at the Department of Chemistry at the University of Copenhagen, which I teach using the peer instruction approach.

The two features I use in Socrative are "Multiple Choice" and "Short Answer".  The video above gives a short introduction on how to do this.

Getting started
* You just make a free account and you get a room number assigned.

* You can easily try it out in your office, as I show in the video, before using it in class

Is Socrative right for you?
* Socrative is limited to 50 responses (actually 60-70 in practice) but you can use it in larger courses because you just need representative feedback to help you decide whether to move on to a different topic or not. The top students tend to vote first and correctly, so if the first 40 votes are from top students you might get the wrong impression that the majority understands the question. However, since "top students" are a minority, most students vote in pairs and not everyone bothers to vote, you can certainly use Socrative in courses where 300 students show up to lecture.

* Students need to bring a laptop or smartphone to vote.  Since many students vote in pairs and you only need representative feedback this is rarely a problem.  At the beginning of each course I send out an email to students telling them to bring a laptop or smartphone and to make sure that it can connect to the campus WiFi.

* Your classroom needs to be equipped with WiFi that can handle the load. Network problems resulting from overload is frustrating to the students. Maybe check with your IT support on this first.

In class
* As I mention in the video, when I ask multiple choice questions I control Socrative from my iPhone using the Socrative Teacher App.

* I don't show the result of the vote. If it's near unanimous there is no point and if it's split it will bias the re-vote.

* When I ask short answer questions I control Socrative on my laptop that is hooked up to the projector, because I eventually want to project the results of the vote and discuss it.  This means I have to flip back and forth between Powerpoint (where the question is stated) and the browser with Socrative.

* While the students discuss and vote walk among them (don't just stand in front of the class) as much as your classroom allows.  This way they can ask you questions and you get a feel for how many students have answered, which is especially important for short answer where you can't follow the progress on your iPhone.

Pacing: better too fast than too slow
* The main complaint about in class voting I have had from students is that it is too slow.

* Multiple choice: When ca 2/3 of the class have voted tell them "one more minute", make your way to the front of the class, tell them "last chance", then stop the vote.

* Multiple choice: If most got the right answer, don't spend a lot of time on explaining the answer.  I usually ask who wants to explain what they have voted for.

* Short Answer: don't wait for everyone to type an answer. You just need 5-10 answers to vote one.

* Short Answer: go through the top 1-3 answers and point out any errors.  If you happen to spot something very wrong in the remaining answers point it out nicely and explain why it's wrong.

* On average I get through about five multiple choice questions and one short answer question in a 45 minute lecture period.

Alternatives to Socrative
There are several alternatives to Socrative such as Shakespeak, Polleverywhere, and Learning Catalytics.  All of these alternatives can be used to collect more than 50 votes but they are not free.

I use Socrative because it is free and easy to use.



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