I thought that my students would have spent too much time measuring objects with a ruler, so I did this part a little differently. I put three segments up on the board, and asked the first three kids that entered the room to measure one of them in both centimeters and inches. I then showed the students that 39.5 inches was about a meter, and then asked how many centimeters the meter stick must be (to bring up the “cents” part once again). Finally, I measured the length of a desk, the length of a book, and the height of a student in both units. Using that data, I had the kids put numbers into their calculators in order to find the conversion. Luckily in all the classes they all said 2.54 cm to an inch.
I then used that to change the length of a girl’s head from inches to cm and the height of a student’s head from cm to inches.
For the next example, I found that I could eat 21 goldfish crackers in 47 seconds. I then talked about both unit rates (goldfish/sec) and (sec/goldfish). And then we found how many goldfish I could eat in an hour.
Lastly, the students noticed that I had grown a beard over the MEA break and I looked to find that the average beard grows at 1/2 inch per month. So we decided to find out how fast my beard must be growing in miles per hour. It gave me an opportunity to talk about scientific notation on the calculator as well – 1.096 * 10^(-8) miles per hour.
The students had trouble with question 1a to begin with, so I will have to have a review day to get them back up to speed with proportions.
