Hands-on Activity: Which Roof Is Tops?

Contributed by: Center for Engineering Educational Outreach, Tufts University

A view from the top of Giotto's Campanile showing the various roof tops in Florence.
How many different roof tops are there?
copyright
Copyright © Wikimedia Commons http://upload.wikimedia.org/wikipedia/commons/6/63/Florence_rooftops.jpg

Summary

When you walk or drive around your neighborhood, what do the roofs look like? What if you lived in an area with a different climate, how might that affect the style of roofs that you see? Through this introductory engineering activity, students explore the advantages of different roof shapes for different climates or situations. They observe and discuss what happens in a teacher demo when a "snow load" (sifted cups of flour) is placed on three model roof shapes.
This engineering curriculum meets Next Generation Science Standards (NGSS).

Engineering Connection

Civil engineers always consider the climate of the area in which they plan to design and build structures. The design and materials chosen for the roof of a building help to maintain the desired temperature within the building and provide a stable structure to protect against the local weather conditions. Engineers use models to test the shapes, materials and functionality of their designs.

Learning Objectives

  • Materials both natural and human-made have specific characteristics that determine their suitable use.
  • Engineering design requires creative thinking and consideration of a variety of ideas to solve practical problems.

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Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

  • Analyze data from tests of two objects designed to solve the same problem to compare the strengths and weaknesses of how each performs. (Grades K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
  • Develop a simple sketch, drawing, or physical model to illustrate how the shape of an object helps it function as needed to solve a given problem. (Grades K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
  • Identify and describe the safe and proper use of tools and materials (e.g., glue, scissors, tape, ruler, paper, toothpicks, straws, spools) to construct simple structures. (Grades Pre-K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
  • Demonstrate that the way to change the motion of an object is to apply a force (give it a push or a pull). The greater the force, the greater the change in the motion of the object. (Grades Pre-K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
Suggest an alignment not listed above

Materials List

Side-view line drawings show three roof shapes: curved, A-frame and flat.
Figure 1. Three roof shapes.
copyright
Copyright © 2004 Tufts University

  • 3 shoeboxes or similar containers
  • 1 poster board
  • 1 newspaper and/or cookie sheet
  • ~2 cups flour
  • (optional) flour sifter or sieve
  • Roof Shape Worksheet

Introduction/Motivation

What shape is the roof on your house? What is the climate where you live? Can you think of reasons why the climate might influence the shape of your roof?

Imagine you live in an area that receives a lot of snow. Architects and engineers who design homes in regions with a lot of snow think about how so much snow adds up on the roofs. If a roof is not strong enough, the weight of the snow (the "snow load") may cause the roof to cave in.

If you were an engineer designing a roof for a snowy climate, what roof shapes would you consider to prevent snow from building up on the roof? What types of materials would you use to build your roof to help prevent snow from sticking to it?

Procedure

Background

A model is a copy of an object that is too big, too small or too complicated, costly or dangerous to study easily. Engineers use models to test and study how well things are built or to test different designs. A "load" to an engineer is any force that pushes or pulls. For example: the weight of snow pushes down on a building, creating a snow load. A wind load pushes on the sides of a building.

Before the Activity

  • Gather materials and make copies of the Roof Shape Worksheet. Obtain flour and containers to hold about 2 cups of flour. A flour sieve is helpful to use, if available.
  • Gather a collection of photographs of different types of roofs in different climates to show the class.
  • Create three model roofs for a class demo. Cut away one end of each box so that students can view the effects of snow loads. Use poster board to make three different roof types, one for each box: curved, A-frame and flat (see Figure 1 or the worksheet). Using a single piece of masking tape, tape each edge of the roof to the open top of the box. Place newspaper and/or a cookie sheet under the testing station to catch any loose flour (to control the mess and collect flour to use again in the next test).

With the Students

  1. Show the class pictures of different roof designs. Talk with them about what types of climates these roofs might be found in. What characteristics make a roof good or bad for a given climate? Incorporate the Investigating Questions into the activity.
  2. Show the class the example roofs that you created. Explain that the flour represents snow and have them make predictions as to which roof would be best for a snowy climate?
  3. Slowly sprinkle "snow" onto the center of the roof as students watch the roof through the open end of the box.
  4. Have students make observations on their worksheets as the snow is applied to the roof and builds up to a weighty amount ("the snow load").
  5. Repeat the process with each model roof type.
  6. Conclude with a class discussion to share and compare observations and conclusions. Refer to the Investigating Questions.

Attachments

Troubleshooting Tips

To avoid a flour storm after done loading one roof type, carefully lift the roof and gently tap the bottom so that the flour falls into the box. Empty the flour from the box into a container to be reused for the next test.

Investigating Questions

  • Predict which types of roofs will cave in to snow the easiest? Why?
  • What happened to each model roof when a snow load was applied?
  • Does the "snow" pile up or slide off?
  • Which roofs sag? What does the sagging mean?
  • Which roofs fall down? Do they fall slowly or all at once?
  • Which roof design is "tops" for snowy climates?
  • In addition to snow loads, what other forces should we plan for?
  • Which roof would you want if you lived in a snowy area? A windy area? Rainy?
  • What roof styles, shapes and materials are best for which climates and weather conditions?

Assessment

Questions: Throughout the activity, ask students the Investigating Questions to gauge their comprehension of the concepts. Refer to the Rubric for Performance Assessment for suggested criteria to assess their knowledge and understanding of the concepts.

Copyright

© 2013 by Regents of the University of Colorado; original © 2004 Worcester Polytechnic Institute

Supporting Program

Center for Engineering Educational Outreach, Tufts University

Last modified: January 16, 2018

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