In a recent class, I showed students a marble and a glass bowl. The two have the same ratio as the diameter of Earth to Jupiter. I asked how many “Earths” would fit into the “Jupiter.” The class volunteered 200 Earths. After producing an ensemble of cups, each containing 50 marbles, we quickly passed the proffered 200 and determined that 700 Earths filled Jupiter. A discussion of the empty space between the marbles led us to the actual volume of about 1300 Earths. How could the students be so far wrong, estimating 200 when 1300 Earths is the correct volume? Have they forgotten simple math concepts such as volume? Were they not sufficiently engaged in class and played Angry Birds instead?
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