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Exploring Paper
Students feel comfortable with paper as a building material
because it's familiar to them and easy to fashion
and fabricate. Still, their understanding of its
properties needs developing. Goldman does this by
having students do investigations with paper, by
exploring how it fails first under tension (pulling
apart) and then under compression (pushing together).
In MOVIE 1, watch students predict where paper strip
with a narrow middle will tear when pulled at both
ends. Listen especially to students' different predictions
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and explanations for where the
paper actually tears during their experiments.
In MOVIE 2, students explore the compressive
strength of paper rolled into tubes of various
heights. (They do not vary the diameter of these
tubes, though this is another key variable in
tube design.) As a teacher, how would you describe
their skills in designing and conducting these
experiments? How would you address these issues
about testing?
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| NOTE: Short,
larger-diametered tubes handle greater compressive
Loads than taller, small-diametered ones. Why
are longer tubes weaker under compression? Notice
also that in both movies teams arrived at opposite
results from the same tests. How did Goldman address
this when it arose? Why did some teams get different
results? How would you have responded?
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