Chemistry First?

I was helping my daughter with her biology the other night.  She is learning about activitation energy and how the role of an enzyme is like a catalyst.  I had to grit my teeth (not for the first time) as I read the text and its nice siimple explanation that a catalyst “speeds up a reaction” by “lowering the activation energy”.  I explained to her that isn’t totally true, but she needed to write it down as the answer to the question on the worksheet that had been copied from the workbook that goes along with the text (the title of the workbook was at the bottom of the copy next to the page number).  As educators, we know that it is more difficult to unteach a wrong assumption than to teach it correctly the first time.  This is not the first time this year I had to do this.

Yesterday, I related this traumatic experience to my coworker,  our biology teacher (my daughter does not go to the same school that I teach at), and she just smiled.

You see, most of our students take chemistry before biology.  Some of them even take physics concurrently.  So, as freshman, our students take a “Freshman Science” which is one quarter chemistry, one quarter biology, one quarter physics and one quarter Earth science.  When possible, the subject teacher is the one who teaches that science to the student in the appropriate science classroom.  Each quarter 20 – 25 students are each in the chemistry room, biology room, physics room, and Earth science room.  As the year progresses, the students move to the next room/teacher.  Once the basic lab techniques are learned, and the equipment unique to the subject matter is mastered, the students learn the basics of each class.

As sophomores, we recommend they take Chemistry (actually, we offer AP Chemistry every other year as a double block class, and this allows the students to be able to fit in AP Chemistry if they are willing to commit to the rigor of the class.)

So, Back to the title of this, Why not Chemistry First?  the mathematics are not more difficult than basic algebra, and as sophomores, they have yet to pick up very many bad Math habits, so stoichiometry can be taught and the fraction button on their calculator can be surreptitiously removed from the front of the calculator (not really, but I have threatened to do it with many a senior).  Their understanding of the “EE” button can be developed before they stumble upon the “carrot” button, so exponential values will be multiplied without mistakes.

As for the science, students will definitely understand the different molecules discussed in biology becuase they know what a molecule is.  The carbon cycle can be taught as a series of chemical reactions, and photosynthesis as an energy process might just be understood a little better.

Just a thought.  It works great for us.

double displacement reactions

trying something new….trying to build a particle model to describe precipitation reactions.  So far, students are  saying that drawing out the ions are helping them understand dissolving, combining reactants and possibilities for recombined products.

The use the solubility rules to determine which is insoluble.

Revisiting something old.  making them write down the rule that proves new molecule is insoluble.

Next up:  molecular; complete ionic and net ionic reactions.

Modeling chemical Reactions

The new trend in chemistry (which I agree with) is to have the students draw chemical reactions pictorially (models). I have been trying to incorporate this idea this year in chemistry, but I have this nagging “bug” in the back of my mind. “do the students need to know how to draw Lewis Structures before we have them representing molecules?

I remember the “Whole Language” idea that invaded the English classroom a few years ago which allowed students to ignore correct spelling of words, so they wouldn’t be throttling the flow of ideas onto a paper.

I feel that, without Lewis Structures, we will be doomed to repeat what history as deemed a bad idea.

I used to do an atoms-first approach to chemistry. Looks like I will be going back to this which can allow for Lewis structures before reactions.