Sunday, January 21, 2018

Do people with lighter skin have different sunscreen needs?


We spent a class period researching in groups and a class period discussing our findings.  The prompt was to construct an argument that skin color matters for sunscreen use and an argument that skin color does not matter.  From there our groups diverged greatly as they built up arguments and pertinent explanations.  
Figure 1:  Whiteboard 1 explores the mechanism by which UV light causes DNA mutations


The wide variety of information in the various whiteboards led to some great discussion on content as well as generic science.  We discussed if knowing the mechanism of DNA damage by UV light is relevant so long as we see the data in Whiteboard 2 (below).  Students split but offered mostly arguments that mechanism knowledge is highly relevant to evaluate the conclusions from the data of skin cancer rates.  Multiple examples were offered such as some races might be located where they experience different exposure to sunlight, different races might also use different amounts of sunscreen on average and reporting of race can be inconsistent.  In general most students felt that just knowing skin cancer rates is insufficient and could be correlation without causation.  
We also talked about the mechanism by which UV light originates and under what conditions an electron can accelerate so much that it produces such high frequency light.  We connected the emission and absorption of light with the Balmer series for hydrogen.  We reviewed the spacing of energy levels and I instructed about the differences in energy level spacings for gaseous atoms/ions compared to molecular excitations.  We connected this later with Whiteboard 6 by talking about how a slight adjustment to a molecule can cause a minor change in the frequencies of light absorbed and how pigments and dye research often utilizes electron rich and electron deficient functional groups to shift color.   
Figure 2:  Whiteboard 2 found cancer rates based on race

Figure 3:  Whiteboard 3 went full “Natural News” to locate some arguments against
sunscreen



This board led to a good discussion on sources of scientific information, how sources manipulate data and experiment into “clickbait” articles.  We posed the question “Are any of these things actually bad or do they just sound bad?”  For example, if sunscreen ingredients are present in breastmilk, is that bad or is it so infrequent and low in concentration that it is irrelevant?  We talked about how the FDA does not have jurisdiction over supplements and how labels for supplements are sometimes shown to be incorrect.  We also compared this board to the risks of not wearing sunscreen using Whiteboard 2 (above).  
Figure 4:  Whiteboard 4 summarized different wavelengths of UV light and nanoparticles
used for sunscreens

Figure 5:  Whiteboard 5 looks at melanin and interactions of sunscreens with UV light

Figure 6:  Whiteboard 6 looks at different chemical structures utilized in sunscreens


Conclusions that students made included that the SPF data they saw suggested that anything over SPF 50 was a marketing scam and was less healthy than using SPF 50 or lower.  We concluded that the mechanisms by which electrons change motion during electronic transitions in molecules are incredibly difficult to visualize and that this uncertainty can be problematic for understanding.  We concluded that everyone exposed to sun should wear sunscreen because melanin mostly protects from sunburn but not from DNA damage.  We saw a variety of organic molecules used to absorb UV light as well as alternatives such as ZnO nanoparticles.  We started our discussion by looking at how 11 cis-retinal converts into 11 trans-retinal when absorbing visible light and this is the mechanism by which our brain becomes aware of light hitting our retinas.  We talked about the breaking of the pi bond before the rotation occurs and later compared this to potential changes in molecular structure when UV light is absorbed by molecules in sunscreen.  
As a teaching lesson I was highly pleased with the variety of topics to discuss and the variety of information students used to make arguments.  Students looked at chemical structures, DNA damage mechanisms, skin cancer data, sunburn data and how UV light itself varies.  We identified what type of light escapes the sun as a subject that requires more research.  We will continue to use this topic throughout our review.  We saw connections to organic chemistry, quantum chemistry, periodic trends and bonding.  It was interesting to the majority of students.  Some students asked what it was like to be sunburned because they had never experienced it before and most students had limited ideas coming into the discussion but left with much better knowledge.  

Sunday, January 14, 2018

The Staff Meeting I Dread - Student Course Selections


A few years ago I had a student take the advanced chemistry class I was teaching.  They did not do well on the first few exams we took and eventually I checked over how they had done in chemistry.  Lo and behold their grade was quite low.  Now when I recruit for IB chemistry or AP chemistry I make it a point to tell the students first that if they did not do well in chemistry that they should take AP chemistry or IB chemistry.  Why go to college and struggle through the material alone when you can work through it with a high school teacher that is likely to be far superior at teaching and where you will move much slower through the material with a lot more assistance?  When I lead with this I often hear a few students laugh as I start the comment before quickly realizing the validity of my perspective.   
So you would think that the first thing that I would have done would have been to talk to the student about their struggles and their ambitions and goals of taking the class.  But this year I had an overwhelming amount of struggle going on from my students and myself teaching new classes.  So instead I deflected and would just get frustrated every time I had to grade another round of tests that had a demoralizing amount of wrong answers.  Then at the end of the year I was talking to the student about college plans.

Me “What are you doing next year for school?”
Students “I’m not sure”
Me “Do you want some advice”
Student “Yeah, well the thing is, I just really love chemistry so much.  It’s my favorite subject, but I’m so bad at it.  I want to major in it, but I don’t know what to do.”

Had my frustrations with their lack of success influenced how I taught this student?  If I had had a better perspective would that student not have those doubts?  I could have taught them better than I did but now they got to carry all of the weight of my decisions.  I was really disappointed in myself because even though I tell students that struggling students should take these classes I had never considered that a student could struggle and love the course.  What had happened to my idealism?  I love chemistry and I don’t love it because of how well I can do problems in it.  I love taking the best results and conclusions from the smartest people throughout history.  I love connecting the macroscopic level with models in the microscopic level so that students can understand what is happening.  Teaching and learning chemistry is my passion and I had missed a chance to share that with someone seeking just that.  
Every year there will be a staff meeting for our department where we talk about scheduling.  I dread this meeting.  Teachers somehow are systemically driven to develop philosophies that only student X belongs in a class and students that do not accomplish Y prior to the class are failures unworthy of learning that content.  There is an angry tone in this conversation and in my view it is because the conversation is unhealthy.  This meeting makes me feel like I've been trapped in the Stanford Prison Experiment and am stuck being a guard. We go to great lengths to prevent students from taking a variety of classes from AP courses to honors courses to regular chemistry.  I wish this were an isolated thing, but I am quite confident that it is systemic because I see it frequently on social media, at conferences and from many teachers beyond my own district.  But I believe very strongly that this mentality of exclusion is damaging and worthy of resistance.  Students in our district are exposed to it every time they sign up for classes starting in 6th grade.  There is an unrelenting pressure put on them that they are not good enough to be where they are and the mental health toll is a disaster.  Think of a student that has been told every year that if they are not at a level of success that they should not be learning about chemistry, or biology or trigonometry.  Now envision what happens if that student struggles in a unit.  Even if they had been successful in everything they had done to that point, any struggle signals to the student that they do not belong in that class.  The conversations we have about course selection likely make children unhealthy in how they learn and I believe also promote segregation based on race and gender.  
We need to stop leading students to evaluate what they should do based on their grades and external mechanisms.  Many would argue that grades are essential to this discussion, but we are talking about 11 year olds.  We are talking about 14 year olds.  How a 14 year old does should have no bearing on whether they can learn chemistry as a 15 year old.  And often the evaluations we do don’t even make sense.  Math skills are not essential to high school chemistry.  High school chemistry uses multiplication and adding.  Students that struggle with manipulations in chemistry class struggle because they do not understand the chemistry involved in the manipulations.  Biology success should have no bearing on how a student does in chemistry.  There are millions of people that were more successful than I was in biology both in high school and in college but only a handful of times have I felt out of place in chemistry or physics.  These perspectives are common and counter productive.  Teachers of struggling students resort to them because of being overwhelmed by the difficulty of teaching.  If a student is struggling with something we should be able to give them specific feedback, have the student improve and continue that cycle throughout the year.  Instead we give students overly simplistic directives to avoid having the conversations we aren’t prepared for.  Work harder, study more, read the text more, etc.  
Students, teachers, parents, counselors and administrators all contribute to the reduction of course selection.  And perhaps all of us suffer the consequences of this as well.  Counselors and administration often use course selection as a means to avoid dealing with problems in classes.  If a class is taught using extreme methods that are exclusive, we help that teacher exclude students rather than address the teaching methods.  This can cause parents to seek exclusivity as a sign of elite status rather than focusing on student achievement.  This can allow negative teacher perceptions to fester.  So let’s break this habit.  If you’re a student don’t allow yourself and your fellow students to be marginalized by course selection presentations.  Ask your teachers thoughtful questions and seek out their passion.  Do the same with counselors.  We all love what we do and chose our profession out of passion.  Help us find our spark again.  Guide us into talking about the best parts of classes rather than the worst so you can walk into a class confident you will learn valuable things rather than being nervous about grading policies.  At some point in your life, no one will care what grades you got at all.  For many of us, that is when we are 17 years old.  So let’s spend less effort maximizing our GPA for little to no benefit and more effort learning about the best accomplishments of humanity.