Lewis, Rules and the Heart of the Matter....

WHAT AM I DOING TO HELP KIDS ACHIEVE?

HOW DO I KNOW WHEN THEY ARE THERE?

WHAT IS THE EVIDENCE?

     Lewis dot structures are an interesting part of chemistry.  Why teach them?  It goes like this...if we can start with a symbol and draw a 2-D structure with a little help we can get the 2-D structure into a 3-D structure.  If we can draw a 3-D structure, then with a little electronegativity, we can begin to understand if the molecule is polar or non polar.  If we can do that, we can begin to predict behaviors on a large scale.   This is the same thing scientists do when they are trying to design new drugs.

     Because of that reason, I believe these little structures have a somewhat important place in the curriculum.  There is a problem.  Research has shown that there are all these "rules" for making lewis dot structures.  Where did these "rules" come from?  Primarily science text books.  Not exactly a good science explanation.  You can imagine...each book has it's own "rules" and the rules work...for some items but then if you draw a larger structure, exceptions (and confusion) occurs.  Interestingly enough, if you go back to the work of Linus Pauling and electronegativity, you start to see a different pictures.  One major idea Pauling examined that influenced electronegativity was bond energy.  It turns out that molecules generally form in a way to have the lowest potential energy in bonds.  The lower the bond energy, the greater the difference in electronegativity....a nice little pattern.  Now, instead of "rules", we are trying to learn a science concept.

     My first approach at teaching this is to first introduce the "rules".  This causes minor frustration.  Students figure out what all other students figure out...don't make much sense and have exceptions.  I have tried to create a "need to know".  Now we are jumping into a POGIL on bond energy and then the TIMU activity on Lewis dot structures.  I did have one student who already started to make the connection of bond energy and electronegativity.  Greater bond energy....lower potential energy (usually favored by molecules) ....also greater change in electrongegativity between atoms in bonds.  One student said, "So if I want to make a molecule, the change in electronegativity might tell me what bonds I might have an easier time forming in a reaction...."  Wow....Much better discussion than saying, "Hey, memorize these rules that only work for a few cases....".  The problem is that as we dip our big toes into the world of energy, there are a million places we can go.  However, it is a nice problem to have.

     POGIL's are great resources.  Sometimes it is a challenge to find the best way to use and assess these.  Here is one thing I am going to try.  We are doing one on bond energy.  I assigned it for homework.  Students will have time to work in groups, check there answers and I will go around to do a "checkpoint".  Then I have a few in which I cut out the key questions and copied them.  I will pass them out at random.  Students will have to find other students with the same key question and then they will have to present to the class.  In academic, we are doing nomenclature.  I am going to do it this year through the POGIL's and then end with "Chem Poker" as the assessment.  We shall see.....  By the way...just did the "moleculer shape" POGIL with the PHET program.  Good program, but hands on models I think would work better...just a hunch and a feeling form the feedback from the kids...

Keep Calm and Teach On....

WHAT AM I DOING TO HELP KIDS ACHIEVE?

HOW DO I KNOW WHEN THEY ARE THERE?

WHAT IS THE EVIDENCE?

     Unless you are living under a rock, you may have noticed that most of the country is being rocked by horrible winter weather.  One snow day...I can see that...so far we have had a week off.  It creates havoc on everything.  Kids are off their schedule, testing is off, schedules are thrown out the window.  It makes for a tough time.  So what is the plan...

     First, stay calm.  Stick with the basics.  When we do get back into session, be flexible.  First, welcome the kids back. Second, develop clearly established goals aligned with curriculum standards.  Also, I know I will have to pick and choose.  Here is what I am going to try and choose...I cannot teach everything.  I am going to shoot for those big ideas that are conceptually rich.  Also, I am looking for activities that have assessments built in that may be performance and not necessarily pen and paper (they are getting enough of that).  Finally, keep going.

     In the past, "Blizzard Bags" have not been too successful.  They were put together and it was hard for parents to get kids to do it.  Here is one possible solution.  What would happen if we had built in "blended" learning from day 1 of the class, even when weather is nice?  Then, after six months of school, going to the blended learning part would be habit and not such a big deal.

     Finally...what about assessment?  Here is where I am at with that.  I was able to get permission to take well established tests (MOSART and LAWSON Scientific Reasoning) and put them in a secure google form.  Students can take the tests combined in one form on any number of devices.  I can get the information instantly and grade it with Flubaroo.  I then paste it into a similar looking google sheet.  The only difference it that each question is "coded".  As an example, question number one might be "Periodic Table".  You can click on the link and it goes to a site of that has inquiry activities on the periodic table.  I am getting closer...will keep you posted.

A difference between boys and girls...

WHAT AM I DOING TO HELP KIDS ACHIEVE?

HOW DO I KNOW WHEN THEY ARE THERE?

WHAT IS THE EVIDENCE?

     I finished watching the video of a lesson I taught.  First about the lesson....What was supposed to happen is that students were going to get data on para and diamagnetic items, define those terms, get that unpaired is paramagnetic and paired is diamagnetic and then link that experimental evidence with orbital diagrams and bonding in compounds.  It was too much and too many links.  Instead, I am going to have students get information on a few metals and compare it to the orbital diagrams and see if they can link it to Hund's rule.  Keep it simple...

     However, that was not the most shocking part of the video.  The most shocking part is the disparity between how boys and girls do science.  I had to break the class into two groups.  One group was doing research as the other half of the class was getting data.  The video showed the evidence...the boys got the data and the girls watched.  When left to interact on the research, overwhelmingly people chose to split up into groups...mostly all boys or all girls.

     A key part to scientific method is actually doing the science, collecting data, and collaborating.  The film was able to catch what I could not see at the time.  My goal is to be more sensitive to this, look for it and to correct it.  I will definitely take a more active role in assigning tasks and monitoring.

A Major Ahaaaaaaa......

WHAT AM I DOING TO HELP KIDS ACHIEVE?

HOW DO I KNOW WHEN THEY ARE THERE?

WHAT IS THE EVIDENCE?

     I had my class video taped.  I am working with some people at Miami and they are doing a study on how instructors teach bonding.  I thought it would be a really great lab.  Students would look at samples of substances that are paramagnetic and diamagnetic and determine the orbital diagrams and confirm Hund's rule.  It was published in J.Chem. Ed.  To make a long story short...it was a disaster.  Way too many concepts.  Magnetism, orbital notation, ions and bonding.  I have already changed the lab.  But there was something else far more interesting.....

     I watched the film.  At one point, I had half of the students in the mini lab (about 5 boys and 5 girls) and half of the class in the room doing research.  After one group got there data, they were going to switch.  The camera person stayed in the mini lab as I went to the classroom to check on the kids.  What I saw on the film stopped me in my tracks....

     Everyone was supposed to get take turns getting data.  On the film it showed all of the boys getting the data and the girls standing back watching and recording data.  The girls were not actively getting the data, just letting the boys do it.  As a guy who has two girls, I was horrified.  I started watching more.  As I was walking around, I counted the number of boys and girls I talked to and it was about the same.  No matter how hard I try to treat everyone the same, it was weird to see such an obvious disparity.  From now on, roles are going to be assigned...hopefully  I will create an environment in which everyone will have the same opportunities....