Why not weigh your own head?

Looking for something fun to do this weekend?  Why not design a way to weigh your own head?  Too weighty?

I was watching QI (Hypothetical) in which Steven Fry poses the question: "How would you weigh your own head?", which I thought would be a fantastic open-ended question to pose to a science class:

Design an method that would allow someone to weigh their own head (within a certain degree of accuracy).  

The method that was proposed was to utilize Archimedes' Principle and submerge your head in a bucket of water while catching the spillage (which I think would be an excellent thing to do in class as well).

Johnny Vegas then wondered if the air pockets in our head would affect the measurement (which I felt was an excellent question and one that a student could pose).  Apparently (according to Steven Fry), the density of the bones in our skull is greater than that of water, so coupled with the lesser density of the air pockets, the overall density of our head is roughly equivalent to water.  The submersion method gets a result nearly equivalent to using a CT scanner to approximate the weight.

What do you think?  Can you come up with an alternative method of weighing your own head?

Preschoolers demonstrate scientific experimentation

I tweeted a review (Wired) of this article: Where science starts: Spontaneous experiments in preschoolers' exploratory play (1). I managed to secure a copy of the article (perk for working at a college) and just finished reviewing it and felt the need to share it with the world.

The study looked at preschoolers (mean age: 54 months) to see if they could isolate variables of a system to infer information about that system (i.e. apply the scientific method) when the probability of information gain is high. Their approach involved a toy that was activated by placing coloured beads upon it. Some of the beads would activate the machine (i.e. it would light up and play music) and some would not. The participants were divided into two groups: the all bead and the some bead conditions. In the all bead condition, the participants were shown that all the beads caused the machine to activate when applied individually. In the some bead condition, the participants were shown that some of the beads caused the machine to activate. They were then provided with two sets of beads (in pairs): one set could be pulled apart to test individually whereas the other had been glued together.

Nearly half of the children in the some beads group tested individual beads in the machine whereas only 5% (1 child) did the same in the all beads group. However in both groups the amount of play with the machine was the same (i.e. the some beads group did not use the machine more and thereby test individually through random chance). In fact, some of the children actually performed a test that the experimenters hadn't thought of; namely holding the stuck pair vertically to test it one bead at a time.

This prompted the investigators to create a second experiment where both sets of beads are stuck together. The results in this experiment were very similar to the first in that nearly half of the some bead group tested the machine by varying contact with the beads.

So what does this mean. Well, what it doesn't necessarily mean is that children are born scientists. What it does mean is that in isolated environments with limited distractions (i.e. limited variables) and limited information (i.e. high probability of information gain), preschoolers tend towards a systematic experimental approach. The authors quickly and rightly note that the current research indicates that this is not true when the systems approach real-world systems with greater complexity.

What does this mean for teachers? Well, it appears that children have an innate sense of experimentation when not overwhelmed by other task demands and there is the potential for information gain. I feel that this should be nurtured with simple experiments that are then discussed and dissected to help develop the habits of mind of successful scientists and critical thinkers. Additionally, there should be teacher led experiments that are more complicated and would overwhelm the students if done alone. This allows for the teacher to model the proper process to the students.

One conclusion that I am tempted to jump to is to bemoan the loss of this 'gift' that students are born with. However, to extrapolate this experiment and apply it to older students or adults would be wrong. I would like to see a similar experiment done with those age groups. My hypothesis is that we would see similar results. So it is not that students lose this basic innate experimental ability; it is more probable that we are not nurturing this skill and helping it grow into a viable ability.

What we need is science based education and critical thinking being taught in primary school and continuing along until high school. Additionally, we need to begin differentiating between teaching science (i.e. the subset of facts and knowledge the scientific method has garnered for us) and teaching with a science based education (i.e. learning to utilize the scientific method, rational thinking, critical thinking, and logic). As the (paraphrased) adage goes: If you teach a student some knowledge, they will know it for a day; if you teach them to think, they will learn for a lifetime.

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1. Claire Cook, Noah D. Goodman, Laura E. Schulz, Where science starts: Spontaneous experiments in preschoolers' exploratory play, Cognition, Volume 120, Issue 3, Probabilistic models of cognitive development, September 2011, Pages 341-349

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One note: the authors of the study did receive a grant from the John Templeton Foundation however, having reviewed the study (with my limited knowledge of cognitive theory) I don't see anything fishy going on.

Walking the Talk

There has been a lot of chatter on the Twitter about life-long learning and how we embody that as professionals and instill the same into our students. It is very easy to say you are a life-long learner and perhaps just as easy to extol the virtues of it to your students. However, I find when trying to instill new habits, a little bit of modeling can go a long way.

If you want your students to become life-long learners you need to not only talk about it - you need to demonstrate it. Start the class with a comment like "I just found this yesterday ..." or "I just learned about this and wanted to share it ...". Show students that knowledge is not something that can be amassed and then ignored.

So, to ensure that I walk my talk I have decided to add a weekly post summarizing the best design and coding resources I have stumbled upon during that week. I normally post them to my class wiki site however things have a way of becoming buried in there.

So what do you think? Is this an idea you could adapt to your classroom? How else can you show your students the benefits of life-long learning through not just your talk but also through your actions?

Feedback: It's a two-way street you know

I've been thinking a lot about feedback and the one-way nature of it in education. Wikipedia defines feedback this way:

Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or occurrences of the same (i.e. same defined) event / phenomenon (or the continuation / development of the original phenomenon) in the present or future.

In many classes, feedback is a one way process: the instructor provides feedback to the student. Typically the student is only granted the ability to provide feedback on the instructor or the course once (at or near the end of the course). This feedback is then not provided to the instructor until after the course has finished. This implies (based on our definition above) that the feedback can not be used to alter the present state of the course that the students are in. This implies an altruistic impetus to the student to even provide feedback (i.e. I will provide feedback not to improve my own state, but to improve the state of future students). I know in my own experience as a student (anecdotal of course, but illustrative) that I only ever filled in the multiple choice part of a end-of-course evaluation unless I was extremely pleased or displeased with the instructor. In addition, by the time the end of term was rolling around, I had forgotten much of the feedback that I had wanted to share.

Looking at it from the other end, this lack of feedback for teachers tends to reinforce the stereotype that teachers are an irreproachable source of knowledge. Stereotypes tend to be more damaging to the one that is being stereotyped that the one perpetrating them. This lack of constructive, useful, timely feedback encourages teachers to accept and embody this omniscient stereotype, and thus not to attempt to become better. Yes, teachers can self-critique and self-reflect upon their own practice (and they should) and change that way. But the system of not permitting feedback for the teacher does not encourage (and in fact discourages) this self-reflection from taking place; in fact it negates any form of reflection of the teacher upon thier teaching practice. It discourages the teacher from changing; what change could be needed by someone that is perfect? By tacitly neglecting feedback, we tacitly accept the idea that we are beyond change and beyond growth; we tacitly accept the idea that we are not learners as we have nothing to learn.

How do we rectify this disparity in our feedback model. The solution is rather simple: do not wait for the prescribed feedback form to come around; be proactive. The exit card strategy is an excellent means of gaining feedback on the lesson from students:

At the end of each class, students are provided a cue card. Upon the cue card they are asked to record the following: One positive item from the lesson, one piece of constructive criticism, and one thing that is interesting (in essence a form of a PMI). Students should be encouraged to do this every class, and to discuss anything they wish. It should also be anonymous.

In my experience, this must be encouraged every class because as students we are very used to having no voice in how we are taught. This idea is not easily dispelled.

It is vital that constructive criticism is acted upon swiftly. Students will realize very quickly if this is a 'sham' when their ideas are not implemented or discussed. Actively discuss the suggestions in class and your feelings on their efficacy.

As I teach in a computer lab, I have digitized my exit card strategy. I use Google Docs to host a form on my course website. The results from the form are dumped into a spreadsheet (think Excel) for me to process. The link to the form is kept on the website and I provide 5 minutes most classes (as I can be forgetful) for students to submit feedback. Here is a sample form for that purpose.

The speed at which I can adjust the flow of the course is empowering. I benefit as a teacher by knowing that my students are understanding my (and our) ideas for the course. I can also gain valuable insights into how my assumptions on how to teach this class may not match the needs of this class. Perhaps more importantly, it shows my students that I am not perfect; that I am growning and learning alongside them; that I make mistakes. But, most importantly, it illustrates those same points to me.

Sample Forms:
General Feedback Form
Exam Feedback Form

On Jack Johnson, Trains and Curriculum ...

I was listening to Jack Johnson's excellent album In Between Dreams today when his song Breakdown came on. Here is an except of the lyrics for those who have not heard this song (which ranks as one of my favourite songs of all time):

I hope this old train breaks down
Then I could take a walk around
And, see what there is to see
And time is just a melody
All the people in the street
Walk as fast as their feet can take them
I just roll through town
And though my windows got a view
The frame I'm looking through
Seems to have no concern for now

When I first heard this album I was living in Cape Town, South Africa working as a waiter at a Mexican Restaurant (I know, it makes no sense). I listened to this song a lot as I was backpacking around Southern Africa and it resonated with my wish to get out of the bus I was in to explore everything that was rushing by me. But the bus kept going ...

Today, it hit me an entirely different way. I was thinking about all the times in school when we are exploring a curriculum mandated topic and the students and teacher would love to stop the curriculum train to explore the current topic. But the train keeps going ...

It seems to me that our current model of education views curriculum as the train; it drives education. This model may be preferred by some as it removes much of the control from the individual teachers, who may choose to teach different topics. However, what it fails to do is to allow for exploration, to permit creativity and to generate passion about the topics. We have a set time to explore a topic, and whether or not we want to move on, we must when the time is up (or we need to dredge through 3 more weeks on a topic no one cares about).

What if we instead switched our model and made the curriculum the track and allowed the teachers to control the train. We would all have a set path to follow, but we would be allowed to stop and gawk when it was appropriate. Or to speed on through when the scenery wasn't to the groups liking. We could even stop the train in the station for a day or so and go on a walkabout; exploring that stop in more detail because our students wanted to.

Imagine that, no longer needing to view the curriculum just through our window frame which, according to Jack Johnson, "seems to have no concern for now", but instead getting out of the train and seeing things unobstructed, freely, and without restraint.

The beginnings of #scisat

So, I had another idea (which I have apparently followed through with ... go me!). I am a huge fan of science laboratories that are open-ended and allow for students to learn important soft skills such as observation, note-taking, hypothesising, problem solving and communication. Personally, I don't care much for labs where a 'correct' answer must be found. In school, I usually reversed engineered them to solve for the answer and add in some experimental error to make it look better.

So, on to the idea. The creation of #scisat. Every Saturday (or Sunday, or apparently Friday as I posted early ... Maple Syrup Festival tomorrow and all) I will post a science idea that helps to foster the skills I listed above. Anything is fair game from labs to demos and journal ling to technology.

If you like the idea and the inaugural posting Spicy Spicy Science, let people know. Let's start #scisat as the way of communicating our ideas with each other. Let's bring science back (hmm, I smell a song ... is Justin Timberlake on twitter?)

Science Saturday: Spicy Spicy Science

So, I like hot food. I like science. Why not combine them together? I was listening to Tom Allen on CBC Radio 2 Shift today (apparently, he provides me with much insight) discuss the Scoville Unit and determining the heat of peppers. Then I got to thinking about converting it into a science lab. Here we go:


So, Wilbur Scoville designed this scale in 1912 to determine and compare the pungency of peppers. This is defined by the amount of capsaicin contained within the pepper. His test, known as the Scoville Organoleptic Test, involves soaking dried peppers in alcohol (capsaicin is alcohol-soluble) and determining by how much it must be diluted with sugar water until it is undetectable to taste. So a pepper with a rating of 2000 Scoville Units must be diluted over 2000 times (its original volume) to render it unpercetable by human taste.

How does this apply to the science classroom? Well, this makes a fantastic open ended science lab that can cover important topics such as: experimental error, subjectivity of methodology, issues with perception, observation and experimental design.

My idea is to provide students with the background information presented above. Have them design an appropriate experiment to determine the Scoville Rating of an unknown sample. Provide each student group with a different sample (I would recommend nothing too hot as it can burn eyes and mucous membranes) and let them run their experiment. Students should have the opportunity to present and discuss the different methodologies chosen by their peers.

Of course, the one outstanding question on your mind is: you want me to have students drink alcohol? Well, it is unfortunate that capsaicin is not water soluble, but it is fat and oil soluble so I would recommend using vegetable/olive oil instead of alcohol in class.

Finally, here is how Scoville did it. He had a minimum of five tasters who were allowed to taste only once per session to prevent prior tastings from influencing their decisions. Because of the subjectivity of the testing, today we test through liquid chromatography.


One more extension is to discuss why drinking water after eating food spiced with capsaicin doesn't work (it is not water soluble). Whereas the drink of choice, beer, has a mild amount of alcohol which can alleviate the burning sensation. The alternative drink, milk, has a compound casein (which is lipophilic or fat-loving) that surrounds the fatty capsaicin molecules and washes them away.

This is a easy to run lab which should provide ample opportunities for students to explore the scientific method while having a bit (or heaps) of fun.

More information on Scoville, capsaicin and peppers:
Wikipedia
Chile Pepper Scoville Scale
The chemistry of capiscum

Top 100 Education Books

Well, I've been sitting on this idea for a bit now and I think it is time to unleash it. I was scouring the net for some amazing way of implementing it, but I can't find anything that doesn't require me to host a web site myself. So, without further ado ...

My idea is to have teachers collaborate and generate the Top 100 Education Books that aspiring, new, and current teachers should read to improve and inform their practice (with thanks to Tom Allen at CBC Radio 2 Shift for the inspiration). This of course is a unending project as new ideas are introduced and new literature produced.

This will be hosted at the shift-ED wiki site and should be ready to be unleashed in its entirety shortly. So, get pondering and get ready to produce the greatest list ever produced (that references books about education).

Theme Days

I've always toyed with the idea of having theme days in my class. People love structure and routine as much as they may need change. Having theme days can allow for the structure, give students the chance to get settled and prepare them to venture into the unknown. My current idea is to spend 5-15 minutes each class on the particular theme. My week would look like this:

Monday Madness -> Show a short video showcasing some cool science
Tuesday -> Individual silent reading
Wacky Wednesday -> Some cool demonstration (may not apply to what we are studying)
Thursday -> Individual silent reading
Famous Friday -> A short bio on a famous scientist

For the silent reading, students would be allowed to read whatever they like (as long as it is not rude). I would also have a variety of reading material in the class library in case students forgot to bring something. I think having students pair up afterwards to discuss something they read is a nice extension.

Sure this would take time away from teaching content, but in the long run I think more science would be learned and taken away.