Modeling Chemistry Workshop – Day 1 Part 2 (plus a bit of Day 2)


So I must say that whiteboarding was one of the topics that I looked most forward to discussing.  For novice modelers (and those of us with more experience) I think this is a large part of what can make your class effective (or not). This is not a topic we quickly covered on the first day.  It was of course (like it will be in your own class) a constant throughout the workshop.  What follows will be some pointers on whiteboarding and general classroom management that we discussed the first day. (As I am writing this I am envisioning maybe pulling together the various whiteboarding related tips into their own post when I finish summarizing the workshop.)

  • Know what ideas you want to get out of the whiteboard session and lead the discussion that way.  This seems like a no-brainer, but I have to say I think this is a component that I have not given enough weight to.  Sure I know what each discussion is about – but have I really sat down and come up with my list of important ideas for each whiteboard session. No.  I need to!
  • Establish your whiteboard norms early in the year. Decide what you want whiteboard sessions to look like and shape them that way during your very first one.  Some ideas:
    • One person talks at a time
    • Everyone presenting talks – ask questions directed at particular students to get everyone talking if needed
    • One clap at the end of each presentation – or have some other professional way of ending the presentations
    • Take markers from all groups when presentations start – this eliminates adding/changing during presentations (and those pesky extra drawings)
    • Make it clear that the presentations are for the students! – students will tend to present to you and look to you for approval – redirect!!
  • Don’t allow use of vocabulary and explanations that haven’t come from your class. Students will want to use words and explanations from previous science classes. You need to make sure they really understand concepts and vocabulary before using them.  You can say “I don’t think we know about that yet in this class” or “That’s not part of our story”
  • Get students involved in asking questions of presenters. Have some question stems posted in your room for students to use to start a question. If a student thinks a presenter is incorrect, have them pose their concern as a question.  Assign groups to ask questions of others (For example, group 1 whiteboards question #1 and asks questions of group 2). The question stems listed below come from a document shared by JillSerling:
    • Clarification Questions:
      • How do you know…?
      • Where did you get…?
      • Why did you do…?
      • What does … tell you?
      • What does … mean?
      • Where on your (particle picture, graph, etc)…?
    • Extension Questions
      • What if we changed…?
      • How is this problem different from…?
      • How is the problem similar to…?
      • How does … compare to …?
      • I did the problem like … and got the same answer, does my way work too?
  • Have a variety of ways to share whiteboards.  Circle discussion, gallery walk, whiteboards grouped together on the floor…  Sometimes every group will present.  Sometimes everyone will have the same question/topic on the whiteboard and only a couple groups need to present.  Randomly select groups to present or pick out those that have whiteboards that will bring up something important (maybe a common mistake or another approach).

Pringles Rocket Can

In the Modeling Chemistry materials, Unit 1 starts with an Exploding Coffee Can demo.  We watched a similar demo – The Pringles Can Rocket.  Here’s a video of it.  After the demo, students should create a three panel storyboard that shows the can and its contents at the particle level 1) when the flame is burning strongly, 2) when the flame is about to go out, and 3) when the explosion occurs.  This is students first attempt at a whiteboard that explains something they don’t fully understand.  Don’t be surprised to hear lots of vocabulary and ideas that will need to be put aside until we understand them more.  Many students will also want to know “the answer” or if they are right.  Try to get them to explain their thoughts as best they can, but do not give them an explanation.  This is your first chance to lead them away from getting answers from the teacher.  But take care that you come across as a caring teacher who wants students to find their own answers rather than someone who is just not interested in sharing knowledge.

In the interest of full disclosure, I have not tried the experiment live in the four years I have taught this curriculum (in part due to inadequate lab facilities). I have shown video clips of the experiment or substituted others.  I am not sure that the actual demo makes a huge difference.  (Although getting to do an explosion is a good motivator for the kids!) As long as there’s a before/during/after type situation without a clear answer as to what particle are doing, I think it could work.

Mass and Change Lab

I won’t go into great detail on the actual lab, since my previous post details it fairly well.  I will mention some changes in the way we did it during the workshop.

We added a seventh part: mixing NaOH and HCl and seeing a color change (phenolphthalein).

For that reaction and the part 3 reaction (forming a precipitate) we used two pipettes as reaction vessels.  After filling , cut the stem off one completely, leave just a portion of the stem on the other. Widen the hole of the stemless pipette, and insert the stem of the other pipette then squeeze to start the reaction.  This might introduce a need for students to take more care in what goes on the scale, but it also uses less chemicals and virtually eliminates clean up.

For parts 5 & 6 (sugar and water & Alka-seltzer and water) we used water bottles so that no beakers/vials needed to be cleaned.

My big realization from the workshop for this lab is related to class time and the difficulties my students have had in getting good data.  In the past, I have had students look for a trend in the data (mass increases, decreases, or stays the same) and if there wasn’t one for a particular part, we would repeat the experiment.  I wanted students to get used to being careful in the lab and to answers not coming from me.  But maybe I need to rethink how much time we spend on this lab (and in other similar pursuits) so that we can get to some really good chemistry that we would otherwise miss out on at the end of the year.


Mass and Change Lab Discussion

For small differences in mass (0.01 g) students may think this is a change (it is not zero!), so you could try relating this to pennies – very small change/negligible.  (Maybe mention those take a penny/leave a penny boxes next to cash registers?)

What do you need students to get out of this discussion:

  • Everything is made up of particles.
  • Particles have mass.
  • A system (what you are studying) can be open (particles can leave or enter) or closed (not open).
  • Mass stays the same when there’s a change in a closed system.  (Law of Conservation of Mass)

The Story So Far

If whiteboarding was the thing I was most excited to brush up on, “The Story So Far” was a close second.  I must admit, in my rush to implement the Modeling Chemistry curriculum and without having attended the workshop I just did not quite see the importance of the story so far.  And so I did not really incorporate it – at all.

But as I had more experience teaching, I wondered if skipping this was a bigger deal than what I first felt (although it’s elimination was more out of rushing than deliberate thought).

So starting this year, I will definitely use “The Story So Far.”  This is the story that your class develops as you explore chemistry. As I mentioned before, if something (vocab or idea) is not in the story – we don’t know that yet.  In some schools they have let students use their copy of “The Story” on tests.

As I complete these blog posts, I will be creating a “Story So Far” post that details what we know at the end of each unit.  The four bullet points at the end of the Mass and Change Lab Discussion above are the first additions to the story!

 Next Up: After Mass & Change, Comparing Volume Units in Modeling Chemistry Workshop – Day 2 Part 1