Wednesday, January 26, 2011

Measurement Unit: Episodes 7, 8 (Liquid Density; Other Measurement Methods)

We're done! With the measurement unit!! All there is left to do is the test. (Or, for my regular kiddies: review, quiz, and then a test after we have remediated the quiz material.)

Lesson 7 in the unit was on liquid density. This one was my favorite, because the kids had to first discuss as a class how to measure the mass of a liquid. After they came up with the general idea, I had them take notes on the definition and procedure for finding "net weight," and we related it to the labels we see on packaged food containers. Kids were excited that they now knew what "net weight" on the corner of their cereal boxes meant!

I then had kids split up into groups of 2 or 3. They were instructed to work on a rather tricky practice sheet of conversions and volume problems, and I pulled out a few groups at a time to rotate around to do parts of the liquid density lab. They needed to measure the density of oil, water, and maple syrup using graduated cylinders and triple-beam balances. (To make this manageable, I gave each group a "clean" cylinder that they would use to find the weight of the container, and whenever they needed to pour the liquid into the container, they would use a "dirty" container that the groups before had used for the same liquid. This way, we didn't have to keep cleaning the graduated cylinders in between every group.) In the end, once ALL of the groups had finished gathering data, we discussed as a class what would happen if we were to pour all 3 liquids into the same graduated cylinder. Then, we tested it! I showed them that even if you flipped the container and straightened it back up, the liquids would still separate themselves. (--To a degree, anyway. The syrup and the water begin to mix gradually, since syrup is water-based and it gets diluted over time.)

It was super fun!! :) Now after this, the kids really have a good grasp of how to measure mass, net weight (net mass), volume, and what all of it means. Lovely!

For my honors kids (who are truly done-done with the whole unit, including the review... the other kids are still a couple of days behind), we followed it up with this: a reading on how to measure an elephant, and another on how to measure the oceans. We discussed the articles after they had read them individually, to make sure that they understood everything in the readings. (I try to insert some relevant reading into every unit to contribute to their literacy.*)

And they got a chance to try their hands at putting together the most complicated concepts in the unit -- making predictions about a 3-D container. (The second page of this was my favorite. It's tricky, unless you really have a good geometric understanding of how the whole container fits together!) Surprisingly, the kiddies didn't really need any help with most of this stuff...

After class, a kid came up to me and said, "These (last problems) are not hard. But, you really need to know your stuff!" It made me feel a little extra proud of them for recognizing their own growth.

I am now looking forward to trigonometry goodness. :)

*What do you do in your classroom to support literacy? I do a lot of making-kids-write-about-stuff, but not enough reading!!!


PS. On the other-things front, I have accepted a job offer from an international school in Berlin! Geoff and I are SUPER excited. It's official news, and all of my bosses know and are happy for me. :) :)


  1. Oh my goodness, Berlin? I hope you like your beers dark and your cabbage sour! :) j/k!

  2. Just caught your PS. Congrats, Mimi! It sounds like an awesome opportunity.

  3. Thank you! :) We're VERY, VERY excited.