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#145 - Dunkin' for Density - 11.15.06
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Bi-Weekly Science Lesson Plan List
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Nov 19, 2006 20:00 PST
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Hi everyone,
This denisty lesson is messy, but worth it! Thanks to Tracy at
sciencespot.net for the original idea! The problem that the kids have to
solve is how to make a fim canister float, sink, or suspend in a tank of
water. It is really easy to make the film canisters float or sink. Most
of the kids figured out that the empty canister would float right away.
The trick is the suspend part. I was very, very picky with my
definition of suspend. The test was that I had to push the canister to
the bottom of the tank, and it had to slowly rise to the top with just a
little bit breaking the water. If it came up too fast, it didn't count.
It drove them crazy, but in a good way! They were so excited when they
were able to do it!
Sanity tip: Place all your materials on a plastic lunch tray so that the
water just lands on the tray. When you are done, pick up the tray and
dump the water back into the tank! Also, students cannot leave until
their tables are completely dry and organized!
They then had to use a balance to find the mass of the canister after
they remove it from the tank and dried it with a paper towel. The volume
was found using the sinking canister and a graduated cylinder. FYI - the
volume for a regular fim canister is about 40mL.
After all their data is collected, they calculated their densities and
placed them on a class chart at the front of the room. I then entered
the data into an excel spread sheet at home (b/c we have macs)and
graphed the results for us to analyze. What is really interesting is
when you look at the data for the suspending canisters, the math proves
that a density close to 1.0 g/ml will make it suspend.
Once you have done the wet experiment, take them to the computer lab and
repeat the experiment on the computer! It was a great reinforcement plus
they had more practice using the formula for density. I also had them
use an online calculator.
Here is the lesson for the Dunkin' part (pdf):
http://www.middleschoolscience.com/density.pdf
Here is the excel spreadsheet for our results:
http://www.middleschoolscience.com/dunkingfordensity0304.xls
Here is a blank excel spreadsheet for you to use:
http://www.middleschoolscience.com/dunking.xls
Density on the Internet Activity:
http://host.explorelearning.com/ESClassic/density.htm
Worksheet for density on the internet (pdf):
http://www.middleschoolscience.com/density-internet.pdf
Here is a free online calculator:
http://www.burtonscience.com/tools/calc/chemcalc.htm
With more and more people using digital cameras, film canisters are hard
to get. You can order them in bulk on ebay or other online sources.
Liz
www.middleschoolscience.com
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