Tuesday, October 18, 2011

Week 6, Marlborough School

Area Activity

October 18, 2011

   Today we did the acre lesson.  Our class was a bit smaller today as some students participated in the once a month Science club.  We still managed to have twenty kids though.  To prep for this lesson I looked up few acre facts, area in square feet: 43,560; length per side of a square acre: 208 feet, nine inches.  I also looked into the dimensions of a soccer field, thinking that it ought to be standard and perhaps we could use those measurements as a tool.  Soccer fields are anything but standard.  A middle school field may be 300 feet by 165 feet, totaling 49,500 square feet... but it may not be.  Note to self: measure to school fields and set aside info for later possible use.  I brought a fifty foot tape measure and a piece of side walk chalk with me for the lesson.
   I began the lesson sending any students who showed up without a jacket back to get one, it was 37 this morning!  When I had everyones attention I pointed to 43,560, which I has written very large on the board.  I asked the kids why this number was significant.  There were a few ideas, among them, the population of all peeps!  One student offered that it is the number of square feet in an acre.  Why does this matter?  We will have this much space to claim for our village!  Each homesteader will get up to 81 square feet of their very own to build on!  I figured 81 based on the white Village Guide Book, which recommends giving each student a 36 foot long piece of string for the perimeter of their claim.  I don't really understand where this number comes from (it is not 1/24 of a real acre or 1/24 of a real 1/2 acre), but it works, so I used it!  Now that we know why 43,560 is important, we need a way to actually measure that and see just how big it is.  If 43,560 square feet fit inside a square, how do you figure out how long each side of that square actually is?  A couple students said divide by four... that didn't work.  Another student offered that 12 times 12 equals 144... on the right track.  I suggested that we simplify this problem.  43,560 is a lot like 40,000; 40,000 is quite a lot like the number 4.  I went ahead and drew a square on the board divided it into four squares.  Eventually we got to 2 X 2 = 4.  However, we took four zeros off of the number we really needed (40,000) and those had to be put back in place for us to find the correct length for one side of a square acre.  We will need to measure out 200 feet, four times!  I think this is going to be hard!
  I took the students and the helper provided by the school out to the school parking lot, specifically the long drive way right in front of the building.  I drew a chalk line at one end and had the students measure out 200ft with the 50ft tape measure.  I drew a line at the 200ft mark.  We formed a group again and I began telling them about pacing... then I backed up a little and we talked about gait.  What is gait?  It is like a door in a fence.  Nope, not a gate, just gait.  I told them that it is the natural rhythm and measure that your body falls into when you walk, comfortably.  I then told them that we were going to learn how many paces it takes each of us to get 200ft, and showed them how to count paces.  This way we won't need measuring tape or string to find out what a real acre looks like.  They went once.  I sent them counting back to the other end.  Many students got the same number, those that didn't I sent back again.  Enough of us had consistent counts to move on.  So, how big do you think an acre is?  From that white sign, to that big tree.  We paced and found we came up a little short for our first side, the students added on the extra 6 paces or so and we moved onto the next side.  From this tree to that stop sign.  Most of the class over shot their 200ft count and went all the way for the stop sign... so we had to do it again.  We chose the average spot to be our next corner.  The students then trudged through the drainage ditches (fortunately it was fairly dry this morning) and the parking lot back toward the building.... X marked the spot and we all stood back and marveled at how much land an acre is.  It is quite large!
  Next we broke into two groups to do a little bit of exploring.  Where do we want to put our acre?  We did not have much time for this... but we did have enough time for the kids to establish that they did not want any poison ivy, bees or dog poop on their land.
  If weather permits, next week I plan to spend the lesson scouting for land and possibly string up the actual boundary line.  Today we learned; how to pace, what gait is, the size of an acre.  We dug deep into our brains and remembered how to find the area of a square.


  1. Hey Sarah,
    This all looks great! If I had to guess.....I wonder if the 36 foot long string if laid in a circle would give you an exact mini-acre.......which should actually have a square footage of 1742? A circle gives the greatest amount of land, so if a 9 foot on each side square is less than the 1/24th maybe a circle gives that much more square footage?
    Have to see if I can dig up my middle school math brains. Also found this site that is great for doing conversions!

  2. Actually.... I have been wracking my middle school brain and the area of a 36 perimeter circle would be closer to 103 square feet. It is still a mystery!

    Thank you for the conversion reference!

  3. It's silly that this is still bothering me months later... Last night I figured out my mistake: I was getting confused by the idea of real feet. Nine feet is equal to 216 mini-feet, which is right on target!