In a conversation about the plastics that end up in our oceans, the topic of straws came up. Not an obvious polluter or even the biggest, but plastic straws are problematic to marine life. We sought out information and found that National Geographic reports Americans as using about 500 million straws a day. Enough to circle the earth twice, and enough to fill 127 school buses. A few students wondered, “How many straws would be needed to fill our classroom?”
Our recent work on volume came in handy as students knew which dimensions they would need to determine the volume of the room. Our room is an irregular shape and we rounded to the nearest whole number, but we determined the volume to be approximately 297 cubic metres. We then determined the volume of a box of straws (honest, they were in the room already), and found it to be approx. 1895 cubic centimetres.
So… how many boxes would fit in the room?
Students determined they would have to make a conversion so both volumes were in the same unit. 100 cm in a metre – no problem. We made the conversions and determined 15 boxes of straws would fit in the room. But, wait. That did not make sense. Through discussions, we realized we would have to account for each linear measurement when converting: length, width and height. So…. 297 cubic metres is NOT 29 700 cubic centimetres but 297 000 000 cubic centimetres. Which means 156 728 boxes of straws could fit into our room. That made much more sense to us. Knowing each box held 500 straws we could finish our calculations.
Out of curiosity, we made both an environmental and mathematical discovery. We’re now considering what to do with this information.