Sunday, May 15, 2011

New lesson posted: Crop Circles 2

Center Pivot IrrigationImage by eutrophication&hypoxia via FlickrIf you're reading this then you're probably already aware that I've added a new lesson to the site:  Crop Circles 2.  Apart from what you can find on the lesson's page, I thought I'd add some more background on the process of creating these activities. 

First of all, I'm not a farmer; although I have to admit there's something about it that I find appealing.  Central-pivot irrigation systems have proven to be a gold mine of content for my site.  They are literally dripping with math (pun intended).  This is the second lesson where they are the topic and I have two more in mind for them as well.  I may try to toss out Crop Circles 3 in the next few weeks since I already have some locations scouted in Google Earth.  The content for that was going to be in Crop Circles 2 but I thought it would be too large.  Number 4 will probably go under a different title.  That one is an ambitious project-based learning activity that I will probably work on over the summer.

A key criteria for topics in Real World Math is that they be visually appealing in Google Earth.  I think most people who have viewed central-pivot irrigation from an airplane are a bit fascinated by them.  Once I have the topic in mind, I need to cruise Google Earth for some good locations.  There are thousands of these fields across the U.S., but there are large concentrations in Washington, Nebraska, Kansas, and Texas.  Once I find some with clear views at different altitudes I begin to drop some placemarks.

Now for the Math.  I already used these for word problems with circle area and circumference in the original Crop Circle's lesson.  At that time I had the idea of finding the area of each ring in the field but that seemed too tedious of a calculation.  That's basically how I decided the new lesson would use spreadsheets.  I needed to find some relevant math content and so I began probing the internet for more information.  There are a few sites and pdf files available but I couldn't find exactly what I wanted to know:  how do they regulate the flow for each ring?  I wanted some specific numbers because I always try to base my material on, well...,  real world math.  In the end I tried emailing some of the manufacturers of these irrigation systems.  To my delight, I received prompt replies from Reinke, T-L Irrigation, and Roberts Irrigation, some of the top producers in the country.  Most of the numbers they supplied me with are incorporated into the lesson.

In the end, I spend the most time creating and formatting the material for teachers.  I try to check my work very carefully because I don't want to put out incorrect information or mistakes.  It's quite fulfilling when I've finished and get to share it with you.  Even more so if I get feedback.  Please don't hesitate to contact me if you have any problems or questions.  Let me know if you'd like me to target a particular grade level or subject.  As always, I hope you find this useful.

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