Main Lesson: Back in the classroom, children will test the strength of post and beam and arch construction.  Materials needed include: wooden blocks or two books, sheets of construction paper, Styrofoam blocks or connection blocks, and uniform weights (large nails, pennies, sinkers, smaller blocks work well.)

Divide the class into groups.  Each group should first set up a post and beam structure.  The posts will be made from the blocks or books, the beam from paper.  Students should the proceed to record how many pennies, for example, their structure will bear until the beam collapses.  They should next create an arch and repeat the experiment.  After all groups have finished, compare the results.  What conclusions can be drawn regarding how much stress each type of structure will hold?

Extending Activities: 
- Each different design can be tested again putting the posts at different distances.  What new conclusions can be drawn?

- Have students compile a booklet from travel brochures, magazines, and newspapers showing different kinds of structural forms.  Look at buildings from other regions of the United States and other countries.  If different forms are obvious, consult a book on styles for more information.

- Use the attached worksheet to help students "act out" structural forms.