| 2 | 3 |
4 | 5
What It Is (continued)
Start with lightweight writing paper. Cut out a rectangle slightly larger
than that needed to make a match to the film canister cylinder. Roll this
paper into a loose tube and put it inside the film canister. Let
it expand so that it rests snugly against the inside of the canister,
making sure that the bottom of the paper rests on the bottom of the canister.
Now, mark a line along the top of the canister and mark another line where
the edge of the paper overlaps itself. These marks define the edges of
the unit rectangle. Cut out this rectangle.
After measuring the surface areas (see below), tape the longer sides of
the rectangle together to form the cylinder. Tape so the edges just meet
and do not overlap.
Cylinder Units of Measurement
The short length of the unit rectangle is the height of the cylinder,
h. The longer length of the rectangle is the circumference of the
cylinder, c. The area of the rectangle is then the area of the
side of the cylinder. The volume of the cylinder is the amount of sand
that it will hold.