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Section 3. Science, society, and the environment are all important in the development of mechanical devices and other technology. 3.1- Evaluating Mechanical Devices. Mechanical devices have evolved over time because of new developments in science and technology. We go from this
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Section 3 Science, society, and the environment are all important in the development ofmechanical devices and other technology
3.1- Evaluating Mechanical Devices • Mechanical devices have evolved over time because of new developments in science and technology. We go from this to..... http://www.youtube.com/watch?v=ff1EGEl3ROs
Using Criteria to Evaluate a Device • Lets say your old bicycle has broken down..you need to buy a new one. How do you decide which one to buy? • Are you going to use it for BMX riding? • Ride it to school? • Riding after dark? • Take a look at pg. 305 Fig 3.1 • Do any of these bikes meet your criteria? • You need to also find a bike that fits in your price range!!
Efficiency and Effectiveness • You can see the difference between efficiency and effectiveness by comparing different designs of bikes. • A one-speed bike is effective in carrying you from one place to another • A 21- speed bike is just as effective as a one-speed, but it’s more efficient. (by changing gears, you can increase your speed and climb hills more easily) • Usually in evaluating a mechanical device, you are looking for the best combination of effectiveness and efficiency at a cost that you can afford
Function and Design • Scientist, engineers and other inventors want to develop mechanical devices that work efficiently and effectively. To do that they consider both the function and design of the device. • Function- is what the device is supposed to do • Design- is the physical form of the device that makes it usable • Think of the bike again..all bicycles carry a person (function) but they have very specific designs
Considering the Environment • We also have to think about the effect of the device on the environment. • For example..spikes in the tires on mountain bikes help you climb slopes, but they tear up the soil and plants even more than ordinary bike tires...
Almost done this section • You will need to read Pg. 308-312 to help with the next activity • Case Study- Evaluating a Mechanical Device When you are finished you need to get into a group of 3-4 and either evaluate: • the “new” mechanical device on pg. 313 OR • Pg. 314 # 3 • Be ready to discuss this in class (will be handed in also) • Write notes under each criteria
Evaluation for Development • If you are buying a mechanical device, you need to think about how to evaluate it. • A thorough evaluation helps you make a better choice and see how you can improve it. • Think back on the old bike we have seen earlier on...aren’t you glad someone evaluated it and saw ways to improve it
You are the designer • You get to design a “new” piece of equipment. • It can be anything that you think you can improve on • Snowmobile • School bell • Skateboard • Anything else……