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Topic:  Block Perimeter Applet at MSTE 
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Subject:  Block Perimeter Applet at MSTE 
Author:  Julee 
Date:  Apr 8 2004 
http://www.mste.uiuc.edu/activity/boxperim/
I found this tool at the MSTE website but it does not seem to be included on
this website as a tool. This tool allows the user to add square boxes to the
"table" adding one unit to the area. The tool will also calculate the area for
the user upon pressing the show area button.
I think this would serve as an excellent tool for students to explore the
relationship between area and perimeter for figures composed of rectangles. At
the middle school level or younger, the teacher could pose some ideas to explore
like
Does the perimeter always change by the same amount when one unit of area is
added?
Can you describe a rule to say how much the area will change in terms of box
placement?
Is there ever a situation where the perimeter does not change when a new square
is added?
Can you find a quick method to find the perimeter of a figure made of many
squares (without pressing the button)?
Which types of shapes seem to have the largest perimeters? the smallest?
Find the smallest perimeter possible for a figure with an area of 36. (Under
what circustances would we want a small perimeter?)
In a geometery class in high school, perhaps students could be encouraged to
come up with their own questions to explore relating perimeter and area. This
could give students a feel for the investigations that mathematicians do and a
tool to test there conjectures.
Some strengths of this program are the ability to change the size of the boxes
to fit more or fewer boxes in the screen. Also, one must ask for the perimeter
to be displayed so students at lower levels can be asked to find the perimeters
giving them practice on figures that they have constructed and can take
ownership of. Perhaps in doing so they will discover that some shapes have
perimeters that are easier to find.
It is frustrating that sometimes boxes disappear in the process of changing the
size of the boxes and the very small boxes are quite difficult to manipulate.
Also the applet is simply an applet with instructions so there is no motivation
or activity included (but that can be good too:).
Julee
 
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