| 2 | 3 |
4 | 5
The central idea of this activity is that when you scale up proportionally
(i.e., keep things the same shape but change the size) weight increases
faster than strength. These beams afford a dramatic demonstration of that
fact, and the activity therefore works quite well as a demonstration.
It can also extend into inquiry, by using the proportional clay beams
formed in the beam molds as the raw material for investigation.
Before beginning this activity, you must build at least one set of beam
molds as described in the inset.
a Set of Beam Molds
molds can be built with scrap lumber and wooden moldings, or
with materials purchased from a lumber yard. For a set, you
will build one mold for -inch-by-
-inch cross-section beams (small mold) and one mold for 1-inch-by-1-inch
cross-section beams (large mold). Materials for one set are
listed on the next page.