Overview and Background: Unit: Bridges

No Performance Assessment

Peggy Gregory : Cheney USD 268

Technology. : Technology : Technology

Cheney : Grades 8 - 8 : Aug. - Jun.

Title:	Bridges
Topics:	Engineering, Bridges, Technology
Time Frame:
Start Date:	-
Status:	Draft
Date Revised:

Other Designers: Don DeMember, science resource teacher, Kingsview Middle School, Germantown, Maryland

Summary:
This unit will look a designing a bridge that is structurally strong.

Print Materials Needed:
The Pitsco Bridge Book
Engineers of Dreams: Great Bridge Builders and the Spanning of America / Henry Petroski. Knopf, 1996.
Bridges: A History of the World’s Most Famous and Important Spans / Judith Dupre. Black Dog & Leventhal Publishers, 1997.

Resources:
Video Bridges from Discovery.com

Resource Attachments:

Internet Resource Links:
Link 1:http://www.school.discovery.com/teachingtools/teachingtools.html
Link 2:http://cl.k12.md.us/bridges/bridgept.HTM
Link 3:http://www.ce.ufl.edu/index.html

Stage 1: Identify Desired Results

State:	KS       5
Title:	Technology
Standard(s):	Experiences in grades 5-8 will allow all students to demonstrate technological problem solving and understand how science relates to technology. Benchmark 1: The students will demonstrate abilities of technological design.

Understandings:
user	Strength depends on structure.

Essential Questions:
user	How do bridges transfer loads from the bridge to the ground? What makes a bridge strong?

Knowledge and Skills:

Benefits and drawbacks of different types of bridges.
Design and build a bridge according to certain principles of engineering.

Stage 2: Determine Acceptable Evidence

Assessment Summary:

Unattached Rubric(s)
Rubric: Bridge Builders
Trait: Cooperative Work Performance Type: Display.
Level 1: Three Points	Level 2: Two Points	Level 3: One Point
Worked cooperatively; carefully prepared plans and sketches; thoroughly researched principles of bridge engineering and applied principles learned	Worked cooperatively; prepared plans and/or sketches; researched and applied some principles of bridge engineering	Had difficulties working cooperatively; failed to prepare plans or sketches; research insufficient, only a few principles of bridge engineering applied

Other assessment evidence to be collected:

Stage 3: Plan Learning Experiences and Instruction

Learning Activities:

Prepare a PowerPoint Presentation depicting bridges that are icons for the cities or regions in which they are located. For example:
The Golden Gate with San Francisco, Brooklyn Bridge with New York City, Tower Bridge in London.

Hand out an assortment of bridge photos from library books and Internet sites. Ask students to look at some pictures and discuss ways in which they are similar and different, using a Venn diagram to organize their observations. Ask the class to speculate on why bridges are shaped differently and made of different materials. Help students make a list of challenges that successful bridge designers must overcome. Some possible answers include earthquakes, strong winds, and changes in temperature.
Divide students into small groups of three or four. Ask each group to select a photograph and research the bridge. Students can write findings on the Classroom Activity Sheet “Bridge Research”

Each group will be provided with:
20 drinking straws
1 meter of masking tape
2 stacks of books or blocks of wood
Meter stick
Jar of pennies
Challenge each group to build a bridge that will span 25 centimeters.
Set the following rules:
ï For the two ends of the span, students will use two stacks or wood blocks placed 25 centimeters apart
ï The only materials students may use for the bridge itself are 20 drinking straws and 1 meter of tape
ï The straws may be shortened, bent or cut.
ï No part of the bridge may touch anything between the two ends of the span.
Allow each group another class period to brainstorm ideas, make sketches, and choose a final design for their bridges.
Students will use another class period to build their bridges with the materials provided.
After all bridges have been completed, have students test their bridges by seeing how many pennies they will hold. Students may modify their bridges, at this point, and then see if they hold more pennies.
Have groups present their bridges and testing results to the class. Ask students to speculate about why bridges were more or less successful than others. What factors went into the strength or weakness of each bridge? What flaws were inherent in the building materials? How were those flaws overcome?

Notes: