Activities Index | Handout | Educator Ideas   Time 10 minutes Materials (per group of two) • 2 unfolded sheets of newspaper • ruler • hand wipes for cleanup Video Connection Show "San Gimignano" from Skyscrapers to explain the basic forces acting on a tower and the importance of foundations. (Check the Program Description to locate the show segment.) Try the Loads Lab. For more information, see Additional Resources. Introduce the Activity Hold up an index card and announce that you want to stand it up on a table. Ask kids if they think you can do this. (They will probably laugh and say no.) Stand the card up on one edge so that it falls over. Ask: Is there anything I can do to make this card stand up? (Kids may suggest changing the shape of the paper by folding it, curving it into a column, or tearing the bottom to make "feet.") Lead the Activity • Remind kids to brainstorm all the ways they can alter the paper. Encourage them to think about shapes and stability. Reinforce that looking at what other groups are doing is OK; this is not a competition between groups, but rather a chance to learn from others' discoveries.   • As groups finish and measure their towers, take a group "tour" of the results. Ask: What forces are affecting these towers? (Use one tower as a model to point out that gravity and the dead load of the tower are pushing down, the surface is pushing back up, and small air movements are adding forces from the side.) What different solutions did groups come up with to counteract these forces? What is similar aboutthe taller structures? (Encourage kids to point out creative uses of shapes, fastening techniques, wide bases, and other solutions to balancing and stiffening their towers.) The Big Idea The strength of a building material can depend on how it is used. Pleating or rolling paper can increase its stiffness. By crumpling, folding, and otherwise reshaping the flimsy flat sheets and by forming a wide base, kids can make the newspaper stand up.  Many forces are at work on towers. Gravity and the dead load of the tower push down, the ground pushes back up, and small air movements push from the side. A foundation distributes the load into the surrounding ground material and can help balance the sideways wind force. The size of the foundation depends on the strength of the supporting ground. A foundation placed in rock can be smaller than a foundation placed in sand or mud. Build on It • Possible outcome: Kids may use the tape to stiffen the newspaper, particularly at the base, or to hold stable shapes such as triangles or columns together.   • Discuss the difference between dead load (the weight of the tower itself) and live load (the weight of the golf ball). Make Connections Physical Education Have kids compare how well they can balance with their feet together and apart. (Apart is more stable.) Brainstorm things that have wide bases for stability (snowshoes, skis, traffic cones). What spacing between their feet feels most stable? How can kids apply this knowledge in basketball, wrestling, or gymnastics?
 This Web site was produced for PBS Online by WGBH. Web site © 2000-2001 WGBH Educational Foundation.