Density Lab Day 4: Layering Predictions

I finally got a chance to post the questions (from day 1 ) on the wall. these are all the questions (paraphrased and combined) that the students had about the Cartesian diver. Ideally, these questions would have been put up Monday eve, so that they were on the wall on Tuesday.I started the day wit a discussion of the questions on the wall. I asked the students to look at the wall and see if they can find the questions that they recorded on the wall. Some were not ton there and I added them. Then I asked the students to look at the questions on the wall and see if we have any incite into some of the questions up there, given everything that we discussed. We started the year talking about particles and what solid, liquid and gas particles look like (how they are arranged). I pointed out the question" "Where does the water go when you squeeze it?". Some kids pointed out that gas particles are spread out and it gets compressed. I asked the students that had this question in their lab notebook to record their claim and give evidence for this question.

The Question of the day was: " Draw a diagram what the test tube would look like if you combine all the liquids." then passed out the whiteboards and had the students draw a diagram of the 4 layers AND give evidence This is where the issues started.

One problem I say was that the students still are unsure how to make a claim. they had "because" in their claim, their evidence was stated like a claim etc. Another issue was that the students did not want to use their observations from the activity on day 1.

For example, Period 1 gave evidence like: "because it is thicker." and "it is denser". I tried to address this by steering them towards the lab, but they could not let go of the thickness issue.

P1 board

P1 board

P2 board

For Period 2, I tried to steer them towards yesterdays lab by redefining evidence as somthing you eoserve directly, and having them open their lab notebooks to the DT form yesterday. This hepled a grate deal. then there were some groups that had it "incorrect", but there logic was correct with their Data. I had some kids share out their thoughts. I then displayed the layering of all the liquids and gave the students a chance to go back and change their board based on the new info. The students then shared out how they changed their thoughts. It went well.

P2 board after they made changes, note the cross out

For period 3, even thought I tried to steer them towards yesterdays lab (like period 2), got similar answers to period 1. The groups struggled with the diff between claim and evidence (did I forget to stress this?) and I had to spend more time on this. I stopped them, had a group present and tried to model how to change Correct their claim they did not get a chance to correct their thinking like P2 due to time.


Similar results as P3 for P5 even thought I stresses the fact that I evidence is something you see.

Started good, but had to include "thickest" (reasoning?)

Period 6 I tried something different.  I gave them 5 minutes to record what they predict the layers to be (without evidence) then I stopped them talked about evidence, and gave examples of the kind of evidence i wanted (i.e. the green is on the botom b/c we tested green w/ blue and w/ yellow and it was on the bottom both times).  I still got  "because it is thicker." and "it is denser" and even a "because its sticky (see figs)  One  group had good evidence, but still felt the need to throw in the "stick/thicker" thing. 

My questions are: do the students need more instruction on claim and evidence? should I include reasining? is it okay to exclude "thicker" as evidence? (it is an observable fact)