Density Unit Day 6: Finding the density

Students doing the lab

Today they are finding the density of the 4 liquids.  I started the day reminding them what we did on Friday,  (we had 3 "theories" as to why they layered...order, we have evidence against...Thickness, we have evidence...density, we do not yet have evidence).  I then did a question of the day where the students got to choose which qeastion they answer 1) how do you find the density of a liquid? or 2)How do you find the volume of a liquid.  This led to a discussion/review.

I posted the mass of the Graduated cylinder on the board and told them to make a data table in their lab notebook that has color,mass,volume, Density and the students worked in pairs to find the density of the objects.

A good lab notebook with typical results

Some groups finished, some did not.

Some small issues:
I had to have a discussion about rounding, most of the students were fine, however they did not know what I meant by "round the density to the nearest hundredths", instead I had to say "round to 2 places after the decimal point.".

I also had a discussion about he units for density.  I still had kids ask what the unit for density is, I do not think they understand the concept of "keeping the units when you multiply or divide measurements".

Many did not subtract the mass of the graduated cylinder. This was evident by their answers. Once they were reminded they were fine.  1 or 2 groups were very confused and I had to explain it to them.

Every once and a while, they would do volume divided by mass.  Again, This was evident by their answers and was easily corrected.

All the above issues increased as the day went  on (attention?) and with lower classes (higher amounts of Sp. Ed. students)


Tomorrow I plan to let them finish/check their work and write a claim about their data.