Designing Efficient Systems: Maximizing Work with Minimal Effort

1. Designing Efficient Systems CHAPTER 3 KEY QUESTION:What methods do humans use to get the most work for the least amount of effort? Looking Ahead No system is 100% efficient. Efficient systems are helpful because they reduce the amount of human and natural resources required to do work. The mechanical efficiency of a simple machine can be calculated. Improved efficiency is an important goal of systems designers. The skills of scientific inquiry can be used to conduct controlled experiments on the efficiency of systems. Improved efficiency has both positive and negative social and environmental consequences.

2. CHAPTER 3 Thinking about Efficient Systems

3. VOCABULARY • lost energy Energy (E) that has escaped from a system • Transformed E. that has changed from one form to another. • Transferred E. that has moved from one place to another

4. 3.1 Energy on the Loose • No system can convert all of its input energy into useful work.(i.e. no system is 100% efficient.) • The energy that escapes is often referred to as lost energy. • Energy is lost in a system when it changed from one form of energy to another (transformed), or when it is moved from one place to another (transferred). • In mechanical systems, energy is most often lost as thermal energy when parts of the system warm up due to friction. • Energy losses are costly and they waste resources, such as fossil fuels.

5. See Pg 60 • Pg.60 # 1,2,3 • Test __________ (Review tomorrow)

6. Test Review • Format – Multiple Choice, Matching, Short Answer • Mix of level 1,2,3 & 4 questions • Study all vocabulary, notes and CYL questions. • Level 4 questions will usually require deeper thinking.

7. 3.7 Explore an Issue CriticallyThe Pros and Cons of Automation • Automationis the use of mechanical and electronic equipment to reduce the need for human labour. • Automation has both benefits and disadvantages. Goal To prepare and present a position paper outlining your position on the future of automation in the workplace. Communicate You must communicate your position regarding automation in an interesting and effective way. You must also demonstrate that you have given some thought to its effects on the economy, society, and the environment. Follow the instructions given for how to write a position paper. Answerable Question: Is the impact of automation on the economy, society and the environment more positive or negative?

8. Writing a Position Paper (Gr 8 version) STEP 1: Take a side on a subject! Tell the reader what your side is. (Well, first you should establish the arguability of the • Is it a real issue, with genuine controversy and uncertainty? Can you identify at least two distinctive positions? Are you interested in advocating one of these positions? Is the scope of the issue narrow enough to be manageable? STEP 2: Organize and outline your reasons for taking that side STEP 3: Conclude your paper by summarizing and solidifying your position

9. Test Review • Chapter 1: What are systems? • What are inputs, outputs and side effects? • Why and how do systems change over time? • + Vocab • Chapter 2: What is work? • What are Newtons? • What are the two types of friction? How do we reduce the effect of friction? • What are the calculations for Mechanical Advantage and Work? (Know how to do them) • Chapter 3: How can we make systems produce WORK with less ENERGY? • What is efficieny? (Both in machines and in society) • How can systems lose energy?

10. 3.2 Efficiency • Efficiency is a measure of how well a system can convert input energy and materials into work or other desired outputs. • A physical system which loses as little energy as possible is considered an efficient system. • Humans are also physical systems. Athletes practice continuously to ensure that they are working as efficiently as possible to increase performance and endurance. • Social systems use the term economic efficiencyto measure how well the social system can achieve its desired output without wasting energy, effort, or materials. • Industries often use efficient machines, such as robots, to increase their economic efficiency. • Efficient systems allow us to get the most benefit from our time, energy, and resources.

11. Test Review • Chapter 1 • Key Terms: Input, Output, Force, Side effects. • What is a possible side effect of a light bulb? Car?

12. Chapter 2 • Key Terms: Simple Machines, output force, input force, Newtons, Friction, Lubricant, Static Friction, Sliding Friction • What are the six basic simple machines? • How could we decrease the effect of friction in a system? • How do we calculate mechanical advantage? • How do we calculate work?

13. Chapter 3 • Key Terms: Lost energy, efficiency • Why are no systems 100% Efficient? • How could a steel bar (lever) lose efficiency when lifting something?

14. Summary – Looking Back Improved efficiency has both positive and negative social and environmental consequences. • Automation has led to improved efficiency in many areas of our lives. • Improved efficiency provides benefits, such as safer work areas, increased productivity, reduction of boring and tiring work, lower labour costs, lower prices for some goods, and automated environmental monitoring and warning systems. • Improved efficiency can also result in disadvantages, such as increased unemployment, displaced workers, loss of traditional skills, and increased environmental stress. • Social and environmental consequences of improved efficiency may be the result of not thinking creatively or broadly enough or the result of setting different priorities.

15. CHAPTER 3 Summary – Looking Back No system is 100 % efficient. • No system can convert 100 % of its input energy into useful work, • Lost energy is energy that is not available to help produce the desired output. • Most lost energy in mechanical systems is in the form of thermal energy, often as a result of friction between moving parts. • Lubricants and other materials are used to reduce the effects of friction.

16. CHAPTER 3 Summary – Looking Back Efficient systems are helpful because they reduce the amount of human and natural resources required to do work. • Efficiency is a measure of how well a system can convert input energy and materials into work or other desired outputs. • Efficient systems allow us to get the most benefit from our time, energy, and resources. • Efficiency has a different meaning when used in general conversation than when used scientifically.

17. CHAPTER 3 Summary – Looking Back Improved efficiency is an important goal of systems designers. • Systems designers must often work with limited time, money, and materials. • Systems must be designed to get a specific job done, while meeting constraints. • Systems designers are imaginative, creative people who collaborate with others to solve problems. The skills of scientific inquiry can be used to conduct controlled experiments on the efficiency of systems. • Many factors contribute to the efficiency of a system. • A system’s efficiency may be investigated by varying factors such as load force, while keeping all other variables constant.