Wednesday, November 19, 2014

The Proctractor Chart, Geography Work Chart #3 (GW3)

Today we worked with the third work chart that goes with the Sun and Earth section of our Montessori geography album (KotU).  We are still talking about the effects of the Earth's rotation and the tilt of its axis in relation to the perpendicular rays from the sun and our seasons.

protractor chart, Montessori, GW3, Geography work chart

The boys liked this chart a lot better than GW2.  GW2 irritated them because we kept moving the sun.  "But Mom!" they argued, "the sun doesn't move, the Earth does!"  Truth be told, they didn't like that this chart requires you to rotate in two directions instead of one but they thought it was a step in the right direction.

What we have here is a rectangle with a circle drawn on it.  The circle has been divided into segments which are colored as follows: white for very cold, blue for warm to cool ("in-between" temperatures), and red for hot.  A slit is cut vertically through the diameter of the circle so that a second circle can be placed inside with one half exposed at a time.  The inner circle is white and slightly smaller than the first in order to expose the colors of the circle beneath. The lines of latitude are marked along the edge.  The solid red line represents the equator.  The dotted red lines represent the tropics of Cancer and Capricorn and the Arctic and Antarctic circles.  The yellow arrow represents perpendicular rays from the sun.


I've placed a small dot of poster putty on the white circle to represent a location on the Earth (you could just do this with your finger).  In the photo below, it is either March 21st or September 21st and the perpendicular rays from the sun are falling directly at the equator.  The poster putty dot is in the blue zone but relatively close to the red.



In the photo below it is June 21st and the perpendicular rays of the sun are falling at the Tropic of Cancer.  Our poster putty dot is now in the red zone.



In the photo below the date is December 21st and the perpendicular rays from the sun are falling at the Tropic of Capricorn.  The poster putty dot is back in the blue zone, but closer to the white zone than previously.


9 comments:

  1. Hm.... a slit and a full circle protractor... I'll have to play with this idea... ;) I have never been 100% satisfied with the chart as it came in training...

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    1. Really? I thought I did it exactly like you did! The instructions in the album for this one might be a little too minimalist for someone slow like me. I really need to see some pictures of yours taken apart. Hey! I've unwittingly reinvented the wheel!

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    2. Well, I did say to experiment too because I wasn't entirely happy with it. The one that I have has no slit, uses half the protractor (so a half-circle) with a little knob sticking out in the middle of the flat side to use a brad to hold it down for it spin on. So as you turn it, you are partially covering the other half of the colored circle (so there is always half of the red/blue/white circle covered).

      There is no one "right" way - and I have been wanting to search for something different ;)

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    3. Oooooooooooooh! I finally understand. I had it in my head from the beginning that the piece with the latitude markings was a full circle. If it were a full circle the only way the image could match yours is if there was a slit. When I asked on the forum what was on the "other side" of the circle and you said it was a half circle I understood. But my mind didn't let go of the "slit" I wondered "doesn't that half circle get stuck on the slit after you rotate it south and then north again?" NO, because there's no slit! NOW I see. Anyway, that's why I made it a full circle anyway. I thought a half circle would get repeatedly caught on the non-existent slit.

      Necessity is the mother of invention I guess :)

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    4. So, the only problem I see with my way is that if you are tracking a location at a high-numbered latitude (such as 90S) it will disappear when the perpendicular rays are at the Tropic of Cancer. Although, we did that during my presentation and it was easy for the boys to see that it was under the white "very cold" section. So, no big deal. But now I can see why it would be designed the other way.

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  2. Goodness, need to totally re-do this chart. Thanks for the clarification!! NOW I get how to use this material.

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    1. Well, definitely read Jessica's comments here if you haven't already. I didn't interpret her instructions correctly when I made it. I do think I USED it correctly though.

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  3. I hear you both LOUD and CLEAR: "Need video tutorial" ;)

    (Although in this case, I LOVE the new idea - still need to play with it, but it is quite intriguing)

    I am getting there.... slowly....

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