Overcoming stereotypes in science

I recently tweeted out a link to this Tumblr (This Is What A Scientist Looks Like) in which they post pictures of scientists in their natural habitat (complete with David Attenborough discussing their mating rituals).  I received a tweet in response to it (from @MissDSciTeacher):

which inspired this post.  What a great way to not only overcome students misconceptions about scientists but also to discuss stereotypes and cognitive biases.

Following Danielle's suggestions, have students come up with what they think a scientist looks like, acts like, or has for personality traits.  Then have them peruse the Tumblr.  At that point lead a discussion about the differences between the perceived idea of a scientist and the reality of a scientist (of course assuming their is dissonance there, which there most likely will be).

From here you can lead the discussion in what causes us to have stereotypes and why they are so difficult to get rid.  This leads perfectly into a discussion of confirmation bias, which is something that should be discussed in every science classroom (and in my opinion, every student should leave school aware of their own cognitive biases and how to correct for them).

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.

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