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Nelson Education > School > Elementary Science > Science & Technology 7 > Student Centre > At-Home Activities > Unit 3
 

At-Home Activities

UNIT 3: STRUCTURAL STRENGTH AND STABILITY

  Getting Started 
  3.1  The Life Cycle of a Product  
  3.2  Product Testing 
  3.3  Planning to Fly
  3.4  Stability 
  3.5  Stabilizing the Tower of Piza 
  3.6  Building Sets for Television 
  3.7  Planned Obsolescence
  3.8  Forces and Structures
  3.9  Applying Forces
  3.10  Loads 
  3.11 Determining Factor of Safety
  3.12  Tension, Compression, Torsion, and Shear
  3.14  Finding Stability in Symmetry 
  3.15  A Stronger Beam 
  3.16  A Stronger Structure
  3.17  Strengthening Structures
  3.18  Getting Under Foot
  3.19  Fasteners and Function
  3.20  Designing a Childproof Container  
  3.21  Making Bridges
  3.22  Bridging the Gap
  Design Challenge
  Unit Summary

 

Lesson Number At-Home Activity
(Parental involvement and/or supervision are essential while students carry out these activities.)
Getting Started: Designing Products

Examine the shelves used for various purposes around your home, looking for ideas you might adapt to help build the CD rack in the Try This activity for this lesson.

3.1
The Life Cycle of a Product
Look around your home, especially in the basement, garage or closets, to find forgotten items that could be put to use by your own family or by someone else.
3.2
Product Testing
Does any household appliance need to be replaced in your home? Consult a consumer magazine to determine the features your family wants and to see how the various brands rank, based on the tests conducted. Remember, however, that many consumer magazines are designed for the American market; brands may differ between Canada and the U. S.
3.3
Case Study: Planning to Fly
What can you find around your home or neighbourhood that was assembled from a kit or built from a set of plans? Who completed the project? Ask them what difficulties they had and what they might do differently next time.
3.4
Stability
  1. Look around at home for examples of furniture, appliances, decorations or other items with a centre of gravity that might not remain over the base during use (e.g., recliner chairs, rocking chairs, portable dishwashers, adjustable arm lamps). Examine these items and see how they are constructed to ensure that they do not fall over when the perpendicular line from the centre of gravity is no longer within the base. When full racks of a loaded portable dishwasher are pulled forward, the dishwasher is extremely unstable and could easily topple forward. Manufacturers solve this problem by installing retractable legs that extend from the floor to the floor to prevent tipping.
  2. Observe how a cat uses its centre of gravity to advantage when jumping and playing.
3.5
Case Study: Stabilizing the Tower of Pisa
Ask family members and friends what they know about the Leaning Tower of Pisa and the experiments conducted there. Compare what they tell you with the material you have researched in this lesson.
3.6
Career Profile: Building Sets for Television
Look for examples of virtual sets on news and public affairs programs. Examine fan magazines of your favourite TV shows to find information on the sets used.
3.7
Explore an Issue: Planned Obsolescence
Look around your home and make two lists. On the first, list the products that are usually replaced as a result of planned obsolescence; on the second, list products that are replaced for "justifiable" obsolescence.
3.8
Forces and Structures
Examine heavy items around your home. Decide where and how you would apply force to these items in order to safely move them from place to place.
3.9
Inquiry Investigation: Applying Force
Prepare a plan for renovating part of your home that would require you to demolish one or more walls or install additional doors or windows. What lies within those walls that you must be careful to reroute? (Possibilities include heating ducts, plumbing, electrical cables, telephone wires, etc.)
3.10
Loads
Examine closets in your home and identify how many different types of clothes hangers they contain. Test the structural strength of each type by determining how great a live load they can handle.
3.11
Design Investigation: Determining Factor of Safety
Consider what kinds of modifications you would have to make to your home to make it accessible to a physically challenged exchange student who would live with your family for a year.
3.12
Tension, Compression, Torsion and Shear
  1. Examine a drapery rod, a venetian blind or a shower curtain rod to determine the types of forces acting on or within them when the drapes, blinds or curtains are in various positions.
  2. Examine any appliance you may have with a retractable cord and determine the types of forces acting within the cord in different positions.
3.13
Choosing Structures
  1. Look around your home and make a list of various types of structures.
  2. Wearing old clothing, test a raw egg's strength by applying a uniform compression to it.
3.14
Finding Stability in Symmetry
Re-examine the items that you identified in the first At Home activity for Lesson 3.4 (i.e., items with a centre of gravity that might not remain over the base during use). Using your new understanding of the effects of symmetrical design on stability, investigate how the designers of these items dealt with the problem of the forces set up within these asymmetrical structures.
3.15
Design Investigation: A Stronger Beam
Look around in the kitchen and bathroom for any structures that include reinforced components (e.g., countertops, cabinetry, cutting boards).
3.16
Design Investigation: A Stronger Structure
Identify the types of beams that are used in the building where you live. (Basements in houses, stairwells in apartment buildings and garages, and ceilings in community centres and arenas often have exposed beams.)
3.17
Strengthening Structures
Examine concrete roadways, bridges and other structures in your area for signs of deterioration. What is being done to reinforce or repair them?
3.18
Design Investigation: Getting Under Foot
Revisit the basements, stairwells, community centres or arenas that you examined in the At Home activity for Lesson 3.16. Examine the structure of the floors in these buildings by looking up at the underside of the floor above you.
3.19
Case Study: Fasteners and Function
Examine tool chests, toy boxes and junk drawers around your home to determine what kinds of fasteners are used on them. If you find several glues and adhesives, note the range of uses each has and the types of jobs for which each is recommended.
3.20
Design Investigation: Designing a Childproof Container
Locate as many childproof containers as you can in the home. Classify the with respect to the types of products they contain and the ease of operation for an adult (you).
3.21
Making Bridges
  1. Using atlases, encyclopedias, travel brochures and other resources, locate pictures of various bridges and list the different types.
  2. Keeping in mind that a bridge is simply a structure that connects two points that have a gap between them, locate as many bridges as possible in your neighbourhood. (A power line allows a squirrel to cross a road; a board can be used to cross a ditch, etc.)
3.22
Design Investigation: Bridging the Gap
Use the pictures you found during the At Home activity for Lesson 3.21 to get ideas for your bridge design in this Lesson.
Design Challenge Note to parents: Since the Design Challenge may be used by teachers as a performance assessment opportunity, parents should consult with the teacher to determine the appropriate degree of parental involvement in their child's completion of the Design Challenge.
Unit Summary

The Unit Summary in your textbook lists all the learning expectations you have covered in the unit and identifies the specific lessons in which the knowledge and skills have been developed.

You can use the Unit Summary to help you create a personal study guide in preparation for an end-of-unit test:

  1. Copy down the list of learning expectations from your textbook. These are grouped under three headings: Understanding Concepts, Applying Skills, Making Connections.
  2. For each learning expectation, locate the appropriate lesson(s) in the unit where the expectation was covered. These are listed at the end of each expectation (e.g., 2.1).
  3. Flip to the appropriate lesson(s) for each expectation and make study notes of the key ideas or skills you learned.

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