Week 26 - Safe Structures, Strengthening Materials and Evaluating Designs
Exercise 4.3
Lesson 4.3: Evaluating Designs from an Overall Perspective
ACTIVITY A: The Right Bike for the Right Job for the Right Price
Required Readings
Science in Action 7 pages 334 to 337 or Science Focus 7 pages none
In this lesson, you will evaluate various bicycles that are on the market. But how do you go about evaluating something? First you have to set up what are called criteria. The dictionary defines the term 'criteria' as a standard of judgment - an established rule or principle for testing anything. In this case, our criteria will be: the use, the cost, the benefits, safety, and the potential impact on the environment.
Consider the following four bikes as to how well they would work in different situations.
BMX bikes are used in many types of competitions like hill racing or stunting. There is a wide range of qualities and prices.
Mountain bikes have many low gears for steep climbing. Many mountain bikes have a full suspension system but can cost thousands of dollars.
Bicycle transport is common in third world countries. These one-speed bikes cost about one month's pay.
Touring bikes are designed for long distance travel over good roads. They can be equipped with saddlebags to carry all your clothes and camping gear. Good bikes can cost thousands of dollars. They are geared to go fast and climb hills. Some have 20 or more gears.
 But bikes aren't the only thing that we evaluate. We make choice everyday on products that we buy, drive, eat, use, and wear. Just walking into a shopping mall sets in motion a whole range of questions in our minds. We have to consider:
Does this product meet my needs?
Will the product last?
Is it aesthetically pleasing?
Is it worth the money?
Evaluating products and making thoughtful choices helps us make good choices as consumers. Who wants to spend money on a product, only to realize later that it doesn't meet your needs? No one wants that! If you have considered all the factors before you walk into a store, you will be more likely to purchase something that meets your needs now and in the future.
