Testing the Strength of a Column

Purpose

To enable students who are blind or visually impaired to discover how much load can be carried by index cards folded into various shapes, resembling columns

Background Information

Columns of various shapes and sizes are part of bridges, overpasses and other structures. Students with a visual impairment can not easily observe whole columns of various shapes and sizes. Some columns are like cylinders, others are box shaped, and some are very wide others are narrow. The shape and size of the column depend on the load they are expected to carry, as the shape affects strength.

Strong column — *An index card shaped like a cylinder is holding two cups, stacked one on top of the other. Both cups are filled with pennies.*

Materials

index cards
one or two rubber bands
tape
light plastic or paper cup
pennies
talking scale
plastic tub or tray

Preparation

Some students may benefit from practice in the folding techniques prior to the activity. Some students with a visual impairment may not be familiar with the shape of print letters. Paper folds must be crisp and uniform. In advance of the activity identify a method for recording data.

Procedure

Fold an index card once vertically at the middle. The folded card will now be shaped like a print letter “V”.
Fold another card vertically into three equal parts (make two folds). The folded card will now be shaped like an uppercase print “N”. Make sure you don’t fold the same way more than once. Fold inward once, and outward once, to make it zigzag.
Next, zigzag-fold another card into the shape of an uppercase print “M” (3 folds). Fold another card into a square (3 folds with equal width, but fold it one way this time, instead of zigzag-folding).
Then, fold a card into a square shape, by creasing it into four equal parts.
Finally, roll another card into a tube. If the paper won’t hold its shape, put tape or rubber band on the card to hold the card into the shape.
Weigh the cup on the scale. Then, weigh 10 pennies on the scale. By doing this, you would be able to tell the weights of 1, 5, 20 pennies, etc, by multiplying or dividing.
Put the V-shaped card into a plastic tub standing vertically, with the V-shape facing upwards. Carefully, put the cup on the top of the folded card. You can put rubber band around the shape to keep its shape.
Slowly, add pennies to the cup one by one. Keep track of how many you have added. Eventually, the card won’t be able to support the weights. It will collapse and scatter the pennies inside the tub. What was the maximum amount of pennies that the v-shaped column could withstand? Record your data.
Repeat steps 3 and 4 for all the other folded columns (N, M, square, and tube). Record your data.
Examine your data and answer the following questions:

Which column, out of the 5, could carry the most weight? Why do you think this happened?
Did the tube carry more weight than the folded columns? Was the square column stronger than the M-shaped column?
If the heights of the column were shorter, do you think the columns could have carried more weight? Why?
What conclusions can you draw from this experiment?