Bridges with Trigonometry Equals Engineering Achievement

By Gathing, Ahmed L. | Technology and Engineering Teacher, February 2011 | Go to article overview

Bridges with Trigonometry Equals Engineering Achievement


Gathing, Ahmed L., Technology and Engineering Teacher


Introduction

Exemplary and fun technology education classes in high schools are always welcome. I introduce bridge building to my ninth graders and other students who comprise the Introduction to Engineering and Technology course within the first two months of the fall semester. In Georgia, Introduction to Engineering and Technology is the first of four technology education classes that students take in high school. Incoming students' knowledge will consist of at least basic algebra and science concepts. As students enter my class for the first time, they are excited to build while learning about different engineering concepts. Building bridges is a great beginning project that allows students to build upon their math skills using basic trigonometry formulas while learning how forces act upon a structure. They also get to enjoy building and testing their bridges. Integrating math into technology education activities is important to enhance their value as "engineering-oriented" activities. Math-related engineering projects have been a missing component in many technology education programs, but activities such as this bridge project will provide credibility to engineering programs. Since most technology education teachers are familiar with the balsa wood project, the implementation of math concepts will not be a difficult concept to conceive.

Background

Bridges

There are many different types of bridges. I introduce truss bridges to students at this level. Students are given the option to build from one of three types of truss bridges: Figure 1. Warren, Figure 2. Pratt, or Figure 3. Howe. These three types of bridges are symmetrical, so, mathematically, members on each side of the bridge should be equal. Another reason I chose these bridges is that students are able to build them within the necessary time period.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

Forces

Four forces are introduced during this lesson: compression, tension, shear, and torque. Compression and tension are the two primary forces acting on the bridge; therefore, I describe them in depth. Compression is a pushing force, and tension is a pulling force, and these can be calculated and described mathematically as will be shown in the explanation of the project that follows.

Project

Students choose a bridge and have to build the bridge using the following teacher-supplied constraints and criteria:

* Using 1/8" graph paper, each student individually must produce a rough drawing of a balsa wood frame bridge (3" wide x 3" high x 8" long).

* The bridge must be constructed with no more than 20' (240") of 1/8" x 1/8" square balsa wood stock, and no less than 16' (192") of 1/8" x 1/8" square balsa wood stock.

* The final drawing will only consist of the front view of the bridge, and the graph paper will also be used to do the math calculations for the amount of stock needed to produce the bridge.

After the students design their bridges and provide mathematical documentation that their bridges are within the constraints, they are given the amount of wood they calculated.

Math Portion

Students will use math equations to predict how the loads acting on the joints are going to affect each member of the bridge. While calculating the loads, students will also learn which members are in tension and which are in compression. If a member is in tension, the answer is positive; if the member is in compression, the answer is negative. I chose dimensions for the bridges that fit within the criteria, but any dimensions will work with your class as long as the equations are correct. The basic math equations needed for this exercise are shown in the next column.

Math equations needed

[summation][F.sub.y] = 0, [summation][F.sub.x] = 0

[A.sup.2] + [B.sup.2] =C2

Sin [theta] = opposite/hypothesis

Cos [theta] = adjacent/hypothesis

Load per joint = Number of joints/total load

Weight = mass*gravity

Sample Exercise

Step 1. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Bridges with Trigonometry Equals Engineering Achievement
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.