My plan is to extend a lesson I have used in the past through the use of imagej to calculate areas of irregularly shaped objects.

In the spring I will be doing a unit on measurement. One of the things I emphasis is that every measurement is an estimate and that trade offs are always made between accuracy, precision and cost.

To do so I explore different ways of calculating areas. Starting with the simple problem of finding the area of the hallway floor outside my room(being careful not to specify what exactly I mean by the "hallway"). I move onto irregularly shaped objects - gum smudges.

Our school sidewalk is covered with different layers, shapes and sizes of gum smudges. I send students out with paper and pencil to do rubbings of several smudges which we then return to the classroom and calculate the areas of.

I ask them to use several techinques to calculate areas, superimposed grid, Pick's Theorem and polygon approximation and to experiment with the calulations to see the trade offs between precsion and cost in time.

I have done this the last couple years and it has worked well. This year I plan to add to the mix some digital photos of the smudges and the task of analyzing them in imagej to find the areas. The challange will be to decide how to best take the photos and what parts of imagej to teach, I want a minimum set so as not to distract from the lesson on measurement. I see this addition as a way to do some differentiated instruction providing a more of a challenge to some students.

I am also toying with the idea of having them use mapping software to map the locations of the collected smudges, but as this does not fit the goals of the unit we will be doing at the time, I am not sure I want to invest the time into it.

Let me know what you think

Arnold

In the spring I will be doing a unit on measurement. One of the things I emphasis is that every measurement is an estimate and that trade offs are always made between accuracy, precision and cost.

To do so I explore different ways of calculating areas. Starting with the simple problem of finding the area of the hallway floor outside my room(being careful not to specify what exactly I mean by the "hallway"). I move onto irregularly shaped objects - gum smudges.

Our school sidewalk is covered with different layers, shapes and sizes of gum smudges. I send students out with paper and pencil to do rubbings of several smudges which we then return to the classroom and calculate the areas of.

I ask them to use several techinques to calculate areas, superimposed grid, Pick's Theorem and polygon approximation and to experiment with the calulations to see the trade offs between precsion and cost in time.

I have done this the last couple years and it has worked well. This year I plan to add to the mix some digital photos of the smudges and the task of analyzing them in imagej to find the areas. The challange will be to decide how to best take the photos and what parts of imagej to teach, I want a minimum set so as not to distract from the lesson on measurement. I see this addition as a way to do some differentiated instruction providing a more of a challenge to some students.

I am also toying with the idea of having them use mapping software to map the locations of the collected smudges, but as this does not fit the goals of the unit we will be doing at the time, I am not sure I want to invest the time into it.

Let me know what you think

Arnold

374:1203

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