Make It Strong Time Frame: 1 Class Period Description: The students investigate strengthening beam bridges by changing the shape of the material used for the bridge. Educational Objectives: The students will change the shape of paper by folding. The students will discover which shape of folded paper supports the most weight. The students will infer how to change materials to strengthen a bridge. TEKS (Texas Essential Knowledge and Skills): Science 112.3.1(A) Demonstrate safe practices during field and laboratory investigations. Science 112.3.1(B) Make wise choices in the use and conservation of resources and the disposal or recycling of materials. Science 112.3.2(A) Plan and implement descriptive investigations including asking well-defined questions, formulating testable hypotheses, selecting and using equipment and technology. Science 112.3.2(B) Collect information by observing and measuring. Science 112.3.2(C) Analyze and interpret information to construct reasonable explanations from direct and indirect evidence. Science 112.3.2(D) Communicate valid conclusions. Science 112.3.2(E) Construct simple graphs, tables, maps, and charts to organize, examine and evaluate information. Science 112.3.3(C) Represent the natural world using models and identify their limitations. Science 112.3.4(B) Demonstrate that repeated investigations may increase the reliability of results. Materials: Card stock Pencils Pennies Rulers Blocks (2 of the same size for each group) Explorer's Notebook, page 4 Advanced Preparation: Cut some card stock into 2 by 11 inch strips. Cut 8 strips for each group of students. Cut other card stock into ½ by 11 inch strips, 1 by 11 inch strips, 1 ½ by 11 inch strips, 2 by 11 inch strips, and 2 ½ by 11 inch strips. Each group needs 1 of each width strip. Procedures: Divide the class into groups of four. Give each group a Record Sheet, 8 strips of card stock, and about 100-200 pennies or other small weights. Say, We are going to be doing an investigation to learn more about beam bridges. You are going to make a simple beam bridge by laying a single strip of card stock across a gap made by two science books. Make sure that the books are exactly 8 inches apart. When you do this controlled experiment, you are measuring how strong each beam is. Have the students lay one strip across the books. Tell them to put pennies on the center of the bridge as a load. They are to keep adding pennies in the center until the bridge collapses. Ask, How many pennies (weights) did it take to make the bridge collapse? Direct the students to record the number of pennies it took to collapse the bridge on the record sheet. Say, For the rest of the investigation, you are going to try to strengthen the bridge by using the pieces of card stock folded in different ways. Make sure that the gap between the books is always exactly 8 inches. Monitor the students as they perform the investigation and record their results on their recording sheets. Discuss the results of the investigation. Have students infer why some designs held more than others. Give each group the different width strips of card stock. Have them perform the investigation with the various widths of card stock. (They do not fold the strips-they use them as they are.) Tell them to record the results on their record sheet. Discuss the results. Formative Assessment: Explorer's Notebook, page 4/Oral Discussion

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