. Spring Story – The Vernal Aeration ., by 3amfromkyoto

Lesson II: Forces at Work
In our study of bridges, we use the example of the suspension bridge to identify load, where load comes from, and distinguish between “dead” and “live” loads. Groups of students form a “human suspension bridge” to feel how loads are distributed in the bridge, and to identify the parts of the bridge that experience tension or compression in response to the applied loads.

. Of Food, Appetites And The Human Condition ., by 3amfromkyoto.

Lesson III: Stress Test
Stress isn�t just that feeling you get when you have a million things to do and only five minutes in which to do them! Engineers calculate stresses in buildings and bridges in order to ensure that the materials aren�t experiencing more stress than they can take, which could result in collapse. In this lesson, students learn what stress means to engineers and, through experimentation, determine failure stresses for a variety of household materials, as the next step in the quest to build a structurally sound model bridge.

Source: The art of bridge construction.