Day 19


One of my favorite books in college was this little tome, “Less Than Words Can Say”

One chapter in particular, jumped out at me this morning as I was grading exams and lab reports handed in to me by the students:

I am actually convinced that what I need to do with my students is get them to unlearn old habits. The specific habit I have in mind is playing the game of school?

What I mean by “playing the game of school” is best illustrated with a specific example.

I had students answer questions regarding the following graph:

Screen Shot 2013-09-18 at 2.33.02 PM

The first thing I want to emphasize is that students had absolutely no problem calculating the slope and the intercept of these graphs.  What was lacking was a decent explanation of the slope and the intercept. Specifically, many of my students were often unable to explain what these things meant in simple terms.

I was hoping to see the slope explained as “The worker gets paid $70 a day” and the intercept as “They start off with $350, maybe this is  a signing bonus?”

Here are four answers read from the top of the pile read in succession :

“This slope represents the average rate of earnings over time”

“Every day the Earnings would go up 70 dollars”

“The slope tells us the amount of dollars per day as the days increase”

“The slope means how many dollars are increased per day”

None of these answers are wrong, but I really have lingering doubts that my students picture an outstretched hand receiving $70 each day of the week or something of that nature

It seems the intercept is something that they have a little bit of a better handle on:

“$350 is the preset amount of earnings already received before nay change occurs with each day”

This one is a little better “The person already starts with $350”


“The y-intercept is the amount of money you start out with which is $350”

What is challenging for me in reading these answers it that many of them are “correct”, but the use of overly formal language leaves me doubting that my students know what they are talking about. The answers seem to be the work of students who want to sound like they know what they are talking about, but in fact are totally lost.

I am not sure what to do about this, and it is something I will spend time on when we do the buggy lab.






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