When was the first time you thought about density? When was the first time you understood density?
I’d imagine most of us conceptualized weight at a young age—perhaps before we were even able to articulate as much. In my case, there were certain objects in my everyday consciousness that felt heavier, and certain objects that felt lighter. My red wooden wagon containing my kid brother qualified as ‘heavy’, but my Hop 100 (a giant rubber hopping ball with handle) was mysteriously ‘light’—despite being the same size as said brother-filled wagon. I didn’t comprehend why two objects of the same size were drastically different weights—at least not until I got through the molecular theory unit in 9th grade physical science.
Admittedly, even then, understanding density— as both an a) ratio and b) volume-related notion—was NOT an easy, intuitive process. I got hung up on seemingly simple questions like: If two objects are comprised of the same material, does the heavier object take up more space than the lighter one? What if the material is different? Oil looks like it should be denser than water, but how come it isn’t? I was stuck between a rock and a hard place in my learning trajectory. And was that ‘rock’ denser than a compressed particleboard ‘hard place’? How would I go about figuring that out?
I would have been better equipped to answer these kinds of questions (without the loads of help I received from my educator parents) if I had been exposed to The Inquiry Project. The Inquiry Project is a free, inquiry-based curriculum that provides 3rd-5th graders with a solid foundation for working with the topic of density in the middle grades. Check out “Measure Lines” by Sally Crissman, Co-Teacher and Curriculum Developer for The Inquiry Project, to learn more about how Inquiry Project guided talk involving ‘felt weight’ and measure line data plotting can prepare today’s 8-10 year-olds for those later ‘dense’ discussions.
For more information, check out The Inquiry Project website at: http://inquiryproject.terc.edu.
And see you next week, reporting on this year’s NSTA presentations!