Density is not typically an easy concept for most middle school students and even more difficult for younger students, but it doesn’t need to be. We all know that D=m/V, but the easiest way I found to explain it to my students was to have them visualize a common dilemma in my home immediately preceding a vacation. For years, as a poor starving teacher, I only had one suitcase, and it was actually a hand-me-down from my mother. It was a medium sized Samsonite, hard cased piece of luggage. When approaching the topic of density in my classroom, down from the attic it came.
My explanation began with an imaginary week-long summer vacation to a low-key resort. The class and I would brainstorm the items I needed to pack for my trip. Generally, the list included items such as a few bathing suits, shorts, t-shirts, a pair of flip flops, some PJs, underwear and a few toiletries. It was obvious by looking at the size of my suitcase that in addition to my meager belongings, I could have probably also fit one of my students in my bag… ok, perhaps one of the smaller kids.
I explained that when I closed the suitcase, it was hard to see, simply by looking at it, how heavy it was. The lesson didn’t stop there. We now planned my one-week ski vacation to Vermont during the February break. Once again, my students and I made up my pack list. The list included a couple of heavy sweaters, long johns, gloves, a hat, boots… as you can imagine, the list went on and on. The question was, where to put it all. Of course, since I had only one suitcase, the answer was easy. Read the rest of this entry »