Engineering Lab

5th Grade Engineering Lab
STEM

5th Grade Engineering Lab

Link to Forces Lab

About This Lab
This lab simplifies the real-life forces and actions that affect structures, in order to illustrate key concepts.

Squeezing (Compression)
Compression is a force that squeezes a material together. When a material is in compression, it tends to become shorter.

Compression: See It In Real Life
The lower columns of a skyscraper are squeezed by the heavy weight above them. This squeezing force is called compression.

Stretching (Tension)
Tension is a force that stretches a material apart. When a material is in tension, it tends to become longer.

Tension: See It In Real Life
The weight of the roadway and all the cars traveling on it pull on the vertical cables in this suspension bridge. The cables are in tension.

Bending
When a straight material becomes curved, one side squeezes together and the other side stretches apart. This action is called bending.

Bending: See It In Real Life
The top side of the metal bar is pulled apart in tension, and the bottom side is squeezed together in compression. This combination of opposite forces produces an action called bending.

Sliding (Shear)
Shear is a force that causes parts of a material to slide past one another in opposite directions. Ý

Shear: See It In Real Life
During an earthquake, parts of this roadway slid in opposite directions. This sliding action is called shear.

Twisting (Torsion)
Torsion is an action that twists a material.

Torsion: See It In Real Life
In 1940, the Tacoma Narrows Bridge twisted violently in strong winds and collapsed. The twisting force that tore this bridge in half is called torsion. Ý

SOURCE: http://www.pbs.org/wgbh/buildingbig/lab/forces.html

Engineering Problem

Adapted from http://www.ctsciencecenter.org/documents/PD/STEMUnits/Bridges_STEM_Unit_CT_Student_Version.pdf

Utilizing the engineering outline, design, test, and build a bridge to successfully solve the problem below.

Traffic in South Asheville has been an ongoing issue for years. As time continues to pass, the traffic congestion worsens. The North Carolina Department of Transportation has studied the issue for years and proposed that a new connector road be built and a new bridge over the French Broad River to relieve the Smoky Park Bridge, Interstate 26 West, and traffic congestion. However, considering the down-turn of the economy, the state has allocated a mere $600,000 dollar budget for each 144 foot section of the new bridge. (The dollar amount and bridge length are fictitious and for the purpose of this problem.)

As a knowledgeable and experienced engineer, your task is to design a bridge that while being cost effective, safe and well-functioning, is also aesthetically pleasing. In order to accomplish this task, you must complete the following:

• Use the website below to research the history of the I-26 Connector. Write about your findings in a brief of no less than ¾ of a page and no longer than 1 full page.

• Decide where on the French Broad River you will build your bridge. Take into consideration where the demand for an alternate route is highest by looking at the maps of the Buncombe County Area, maps from proposed connector routes, and where you think the most cars travel. Indicate your chosen location on the French Broad River map provided.

Find more about the I-26 Connector and area maps:

http://www.ncdot.gov/projects/I26Connector/

Design

There are several bridge design websites that will help you plan your design.

I have grid paper for you.

Building Models

• Gather materials, and, utilizing your blueprint and research, begin constructing a model bridge of your design. Drinking straws, paper clips, string, and tape.

Testing

• Test your model to make sure that it can withstand a load of at least 2,000 grams, when such load is placed at the center point of the bridge.

• Record observations and collect data.

Analyze Data

• Analyze your data to determine if you need to redesign your model and retest so that your bridge meets the requirements.

Redesign

• If adjustments must be made to your design, make your modifications and document such changes.

Retest

• Test again to make sure that your model can withstand a load of at least 2,000 grams, when such load is placed at the center point of the bridge.

• Record observations and collect data.

In the design of structures there is a need to consider factors such as function, materials, safety, cost, and appearance.

Communicate Results:

Upon completion of your bridge design and functioning model, you and your teammate must present a design portfolio at the city official meeting (held within your classroom) where the city officials (your classmates) will vote on the best-suited bridge for the city. A successful design portfolio should provide full explanation of why your bridge design should be chosen, and, should answer the following key questions:

1. What type of bridge did you and your teammates design and why?

2. Where on the French Broad River are you and your teammates planning to build the bridge and why?

3. How much will the bridge cost to construct?

4. From your design, what would you predict is your bridge’s ability to support a load? Explain.

5. Why should NCDOT officials choose your bridge design for their new bridge project?

Write a persuasive paragraph explaining why your bridge design should be chosen to be the new French Broad River Bridge.