Monday, March 2, 2015

speeds and number sense

Today, one of my students told me I was getting really weird because I wanted to know which was faster, a sloth or a snail, and by how much.  This required them to do  bit of an internet search.  Another class got to compare the speed of a cheetah vs man and this lead to a discussion on average speed via a math equation vs reality.  The other question I asked required them to convert units so they could actually compare 22 in/sec or 1 mph.  Turns out its the 22 in/sec by about 5 in/sec.  I need them to be fluent in conversions for their science class. The science teacher and I work together.  So last week, we looked at information given in parts such as 18 miles in 15 min to obtain a speed of miles per hour rather than miles per min.  This gave me a chance to initiate the idea that if you get information in one unit, it does not automatically mean that you must present it in that unit.  You need to step back and check to see what the common usage is.  In the 18 miles in 15 min, students were giving me the answer in miles per min even though they normally give speeds in miles per hour. 
The next step in this is to find information such as a guy ran the 100 yard dash in 28 sec so how fast was he going in mph and could he really maintain that speed. 
This falls under the student considering if the answer is reasonable.  Too often my students say yeah its reasonable without stopping to really think about the information and I am hoping things like this will improve their internet research skills and help them develop the number sense they really need in everyday life.