Teachers TryScience

Bridging the gaps!

May 24 2016

Source: LLF India

Summary Information

Topic:

Algebra

Geometry

Workplace Skills:

Problem Solving

Teamwork

Target Grade (Ages):

Grade 9 (Ages 14-15)

Diversity Indicators:

Grade 9 Students

Tab Wrapper

LESSON

Goals and Prerequisites

Goals:

To understand various set of angles when a transversal intersects a set of parallel lines i.e. learn to prove two lines parallel by measuring different pairs of angles!
To recap the learnt properties of a triangle and prove that the sum of the angles of any triangle equals 180⁰.
To introduce students to a basic concept of engineering to help them understand why certain shapes are used, and which shapes withstand the most force.
Focus on how bridges are engineered to withstand weight, while being durable, and in some cases aesthetically pleasing.

Prerequisites:

Definitions of line ray and angle.
Knowledge of parallel lines and different type of angles.(acute, obtuse etc.)
Measure angles using a protractor and a compass.

Instructional Objective(s)

At the end of the lesson, students should be able to:

Visualise lines, angles and triangles in the objects we see around us.
Identify alternate angles, corresponding angles, vertically opposite, interior angles and linear pair of angles.
Sum the measure of the three angles of any triangle to get 180⁰.
Describe and design model truss bridges.
Identify effective geometric shapes used in bridge design.
Identify several factors that engineers consider when design bridges.

Instructional Resources

Background:

Instructional Resources

Introduction –

Ascertain students’ prior knowledge about parallel lines, angles and triangles. Induce inquisitiveness among the students by encouraging a large group discussion about the angles and triangles they use or see round them. Put forward some questions like

Where do you see angles and triangles around you? How can you differentiate between various angles and triangles? To recapitulate types of angles and triangles learnt show the video with link.

https://www.youtube.com/watch?v=UgfSwlqi4Qg https://www.youtube.com/watch?v=mLeNaZcy-hE.

After group discussion on triangles around us, show them the video with link

https://www.youtube.com/watch?v=BU6OUC4Zv9w

facilitate their thinking process.

What would happen if all the bridges in India disappeared overnight?
How and where is mathematics involved in the bridges that you see or use?
How do you think the people in the early ages made bridges without the knowledge of mathematics? What is the advantage of today’s bridges over the earlier ones?
How will you know that a given pair of lines is parallel? List different ways in which you can prove two lines parallel (introduce concept of corresponding, alternate, interior angles.

To conclude take the class through the PPT to teach them various angles formed when a transversal intersects a pair of parallel lines.

Divide the class in groups of 6 and give each group a K-W-H-L chart. Have each group fill ‘K’ , ‘W’ and ‘H’ columns about lines, angles and triangles. Check and discuss K-W-H-L charts with each group.
Inform the students that they are going to design a sturdy bridge and build the designed bridge using the given material.
Working as engineering teams, students design and create model beam bridges using plastic drinking straws and tape as their construction materials.
Their goal is to build the strongest bridge with a truss pattern of their own design, while meeting the design criteria and constraints. They experiment with different geometric shapes and determine how shapes affect the strength of materials. Let the competition begin!
Pass the set of required stationary and material to each group.
After the bridge is constructed they need to measure certain angles as instructed in the workbook and record the readings.

Integration of the concept with other STEM Subjects:

Topic as integrated with Science- Realising the importance of mathematics (measurement, shapes) in the field of science while developing strong bridges, learning about the forces acting on it, resonance etc.

Topic as integrated with History- Learning about the history of bridges, their significance in the development of a city and gaining knowledge of various famous and important bridges across the globe.

PPT- Bridge Engineering

Materials:

Material Needed (Please provide worksheets, rubrics, charts to be used for this lesson here – embed the files)

For each student:

Engineering Design Process Workbook.
Handout for students needing assistance to build the bridges
KWHL Chart: http://coolaustralia.org/wp-content/uploads/2013/03/KWHL1.jpg

For each group:

25-30 strong sipping straws/ ice cream sticks/toothpicks (whichever is convenient to procure)
scotch tape
Sticking glue
Scissors
Pencil and Eraser
Foot scale
Protractor
A wooden support structure with a pair of piled bricks or wooden blocks on which the bridge will mount.

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For the entire class:

Bridge Engineering-

Water colour box and brushes
Sketch pen set/ crayon set
small paper cup
50-80 coins (to use as weight)
Blue glaze paper sheets (to depict water on the board)

Handout for students

Procedure:

Engineering Designing/STEM Based Project

Introduction

To start, you may want to introduce students to Bridge Building which falls under Civil Engineering with the video given below.

https://www.youtube.com/watch?v=KA01ds_6W54

Part1 – Students learn about different types of bridges and Design one of their own.

Tell the students that they are going to watch a story unfold about how and why the concept of bridges began with the video

https://www.youtube.com/watch?v=NE2VchWrtLM

After a short discussion, take them through the PPT to understand the science and mathematics involved in bridge building.

Now tell them that today they all are architects and design engineers and have to help a forlorn village which lacks convenient connectivity with the closest habitation as they need to cross the mountain to reach the nearest town situated on the neighbouring mountain. Initiate a discussion to understand the kind of difficulties the villagers must be facing.

Let the students sit in the made teams and discuss the problem, to brainstorm ideas, make sketches, and choose a final design for their bridges. Also ask them to choose a name for their design team. (Encourage students to build a truss bridge as we are dealing with triangles). If need arises and time permits, allow each group one class period to research bridge engineering. They should find out the basic principles of the truss bridge.
Provide them time to work on their design keeping the strength, length etc in mind. Guide them to work backwards on how much material they have, the constraints, so to be able to make the most of the little given!
Before they begin Bring back the class as a whole group and set the following rules:

For the two ends of the span, students will use the given base with the blocks placed 25 centimetres apart. No part of the bridge may touch anything between the two ends of the span.
The only materials students may use for the bridge itself are 20 drinking straws/ ice cream sticks. The straws may be shortened, bent, or cut
Their bridges will be judged on their capability to hold weight of the cup full of coins. The endurance of each team’s bridge will be tested and if they fail they need to redesign it.

If the students need help at any point, let them refer to the handbook given to them.
Give each student a workbook to note their engineering process in it.

Part – 2 -Constructing the Bridge

Instruct and encourage each team to distribute their workload evenly among the members for timely completion of the project.
The students and teams who need assistance can be guided with useful inputs which are available to the teacher.
While constructing the bridge they need o keep in mind the width of the bridge and what kind of vehicles they expect the bridge to facilitate. (Teacher can keep kindling their imagination by asking questions)

Part – 3 –Bridge testing and redesigning

Provide students time to make a presentation of their models with an interesting name and details.
Again Orient students on the timeline and the roles for each student.
Have students test their bridges by seeing how many coins they will hold. Students may modify their bridges, at this point, and then see if they will hold more coins.
Have groups present their bridges and testing results to the class. Set a minimum bar for all bridges, if they are unable to hold the set number of coins, ask the team to rethink and redesign or make required alterations to make their bridges stronger
A question answer round is opened to the student which is led by the teacher

Let students to speculate about why some 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?

To conclude ask the students to fill the summative questions in the workbook

Culminate the activity by asking students to reflect on the entire design process. Have students fill in the L column of the K-W-H-L

Rubric

Rubric Presentation

Extensions

Truss patterns are used for more than bridge design. Ask students to note all the real-world applications in which they see truss systems. Possible examples: construction of other structures, plus ramps, radio towers, crane arms.
Students work on the engineering process for other types of bridges like beam, cantilever and arch bridges.
Students can remake the models of some famous bridges of the world. E.g. Howrah Bridge, London Bridge etc.

Assessments and Rubrics

Pre-activity – Discussion questions

How do you think the people in ancient times made huge monuments without the knowledge of numbers and shapes?
Today, where and how is maths used in civil engineering?
Why are bridges an important aspect of our progress and development?
Why do we usually see bridges made of triangles?
If the Indian government requires states to inspect and rate all bridges at least once every two years. Describe ways that technology can be used to make monitoring and inspection of bridges more efficient and effective.

Activity Embedded – (Formative Assessment)

Prediction: Before testing, ask teams to predict how much weight will collapse their bridges. Record predictions on the board.
Evaluate the students understanding, application and learning through the process.

Post activity –

Evaluate the student’s workbook to gauge the mastery of the concept
Show and test – Evaluate the student’s model and involvement in the given task using the given rubric.
Assessment- Evaluate the students understanding and application in the given summative assignment.(Reviews attached in the workbook)

Bridge Engineering Activity

Rubric

Rubric Presentation

Credits

Credits