Introduction
This lesson is based on materials presented on Exxon's teachers'
network listserv.
Activity
Supplies: rulers, compasses, calculators
(TI-108), staplers (or Scotch tape), colored index cards of two sizes.
Basic Instructions
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Dimensions
w is the width of the card
l is the length of the card
x = 1/4 * w is the side of the square in each corner of the card
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Draw two horizontal lines and two vertical lines as shown above.
Pull the sharp point of a compass along all four lines (use a ruler) in
order to make the creasing precise.
Make four short cuts from the points marked P to the points marked Q.
Fold along the drawn lines, forming an open rectangular box. The
squares on the corners will double the thickness of the two short faces of
the box.
Staple each short face together (one staple is enough). Or you may use
Scotch tape.
1. Each student gets two index cards, 5 by 8, and 3 by 5
inches. Students are instructed how to make boxes and that the
measurement should be done in inches (and 1/16 of inches). They are
asked to:
make two boxes of different sizes
compute their volumes
compare their volumes.
2. Computation of the volumes.
BIG BOX
| x = 1 1/4 |
inches in height |
| y = 2 1/2 |
inches in width |
| z = 5 1/2 |
inches in length |
| V = x*y*z |
volume in cubic inches |
Compute V as a mixed number:
[1.25]
[*]
[2.5]
[*]
[5.5]
[=]
17.1875.
Write down 17.
[-]
[17]
[*]
[16]
[=]
3.
Write down 3/16. The answer is V = 17 3/16 cu. in.
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SMALL BOX
| x = 3/4 |
inches in height |
| y = 1 1/2 |
inches in width |
| z = 3 1/2 |
inches in length |
| V = x*y*z |
volume in cubic inches |
Computation: Write x, y, and z as decimals.
x = 0.75
y = 1.5
z = 3.5
Compute V as a mixed number:
[.75]
[*]
[1.5]
[*]
[3.5]
[=]
3.9375
Write down 3.
[-]
[3]
[*]
[16]
[=]
15.
Write down 15/16. The answer is V = 3 15/16 cu. in.
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3. How many of the little boxes will it take to fill the big box?
We need to compute the volume of the big box divided by the volume of the
little box.
The volume of the big box is 17.1875 cubic inches, and
the volume of the little box is 3.9375 cubic inches.
[17.1875]
[/]
[3.9375]
[=]
4.3650793
It takes about four and one third little boxes to fill the big box.
4. Other cool things you can do:
You may make boxes out of old greeting cards.
If you make two that are (almost) the same size, one can
serve as a lid.
Handles can be made for the boxes, turning them into baskets.
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