Tuesday, July 22, 2014

Making video lectures: Powerpoint screencasts

I have previously discussed the many advantages of video lectures compared to live lectures. Here discuss how I make most of my video lectures.

Almost all my video lectures are screencasts of Powerpoint presentations made using the screencasting software Screenflow.  Screenflow only works on Macs but there is a very similar program for Windows called Camtasia.

The two videos above nicely illustrate how I do it: you simply go through your Powerpoint presentation of your computer and Screenflow records what's happening on the screen and what you say.Then, usually after a bit of editing, I upload the video to my Youtube account.

There are two main differences between the videos and my approach: One difference is that I use the earphones with microphone that came with my iPhone for a better audio recording. The other difference is that I don't record myself talking with my webcam because I personally find these "talking heads" distracting when I watch such videos.

There are other ways of recording Powerpoint presentations.  The reason I used Screenflow is that
it has very powerful, yet easy-to-use, editing capabilities for fixing mistakes. The same is true for Camtasia and this video gives an example of a correcting a mistake.

Some practical tips
* Once you start a recording, don't stop.  If you make a mistake, keep quiet for a moment and start that part over.  You can fix the mistake by editing and the quiet moment allows you to cut without interrupting the narration.

* Keep quiet for a second before and after changing slides. This allows you fix errors on a particular slide without affecting other slides.

* Once you finish recording a video your first instinct will be to delete it.  Try waiting a day and listening to it again. I bet you'll feel better about it.

* Hosting your videos on Youtube has many advantages such as optimized views for mobile devices and good buffering for slow internet connections.  You can control who can access your videos on Youtube, though there is really no good reason not to share the video with everyone.

* However, if you want to host the video in a place not recognized by Screenflow or Camtasia, such as a university server, you can export the movie to a file and upload the file.

Other uses of screencast
Screencasting in general, and Screenflow and Camtasia in particular, are very versatile tools that can be used for many other things.

For example, I frequently use Screenflow to grab fragments of Youtube videos or simulations to include in my Powerpoint slides.  Here are some examples:

A screencast is also an excellent way to show how to use a particular program or website.  Here I show how to use a particular feature of the program MAPLE.

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

This work is licensed under a Creative Commons Attribution 4.0

Thursday, July 17, 2014

My new research impacts this week

Your new research impacts this week

Jan Jensen

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Sunday, June 29, 2014

Video lectures

Video lectures vs live lectures
* 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.

* 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.

This work is licensed under a Creative Commons Attribution 4.0

Saturday, June 28, 2014

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.

This work is licensed under a Creative Commons Attribution 4.0

Sunday, June 22, 2014

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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Wednesday, June 18, 2014

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:

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

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Saturday, June 14, 2014

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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