SCIENCE 10
UNIT B: ENERGY FLOW IN TECHNOLOGICAL SYSTEMS
SCIENCE 10
Program of Studies
Unit B: Energy Flow in Technological Systems (Science and Technology Emphasis)
Overview: The first and second laws (conservation and conversion) of thermodynamics have been useful in the development of modern and efficient energy conversion devices. Students investigating mechanical energy conversions and transfers in systems will recognize that while energy is conserved, useful energy diminishes with each conversion. Students learn that energy can be observed only when it is being transferred, and that mechanical energy can be quantified. Energy conservation and conversion concepts are applied by students to explain energy conversions in natural and technological systems, and to investigate the design and function of energy conversion technologies.Links to Science
The following science concepts are related to the content of Unit B.Concepts
Science Course and Unit
- heat energy needs and technologies, thermal energy, heat transfer, energy conservation - Grade 7 Science, Unit C: Heat and Temperature
- forces on and within structures, direction of forces - Grade 7 Science, Unit D: Structures and Forces
- transmission of force and motion, simple machines, measurement of work in joules - Grade 8 Science, Unit D: Mechanical Systems
- forms of energy, energy transformation, renewable and nonrenewable energy - Grade 9 Science, Unit D: Electrical Principles and Technologies
- Which came first, science or technology, and is it possible for technological development to take place without help from pure science?
- How did efforts to improve the efficiency of heat engines result in the formulation of the first and second laws of thermodynamics?
- How can the analysis of moving objects help in the understanding of changes in kinetic energy, force and work?
- Why are efficiency and sustainability important considerations in designing energy conversion technologies?
Key Concepts
The following concepts are developed in this unit and may also be addressed in other units at other grade/course levels. The intended level and scope of treatment is defined by the outcomes below.- forms and interconversions of energy
- technological innovations of engines that led to the development of the concept of energy
- one-dimensional motion
- mechanical energy conversions and work
- design and function of technological systems and devices involving potential and kinetic energy and thermal energy conversions
- efficient use of energy, and the environmental impact of inefficient use of energy
Outcomes for Science, Technology and Society (STS) and Knowledge
Students will:- Analyze and illustrate how technologies based on thermodynamic principles were developed before the laws of thermodynamics were formulated
- illustrate, by use of examples from natural and technological systems, that energy exists in a variety of forms
(e.g., mechanical, chemical, thermal, nuclear, solar)
- describe, qualitatively, current and past technologies used to transform energy from one form to another, and that energy transfer technologies produce measurable changes in motion, shape or temperature
(e.g., hydroelectric and coal-burning generators, solar heating panels, windmills, fuel cells; describe examples of Aboriginal applications of thermodynamics in tool making, design of structures and heating)
- identify the processes of trial and error that led to the invention of the engine, and relate the principles of thermodynamics to the development of more efficient engine designs
(e.g., the work of James Watt; improved valve designs in car engines)
- analyze and illustrate how the concept of energy developed from observation of heat and mechanical devices
(e.g., the investigations of Rumford and Joule; the development of pre-contact First Nations and Inuit technologies based on an understanding of thermal energy and transfer)
- Explain and apply concepts used in theoretical and practical measures of energy in mechanical systems
- describe evidence for the presence of energy; i.e., observable physical and chemical changes, and changes in motion, shape or temperature
- define kinetic energy as energy due to motion, and define potential energy as energy due to relative position or condition
- describe chemical energy as a form of potential energy
(e.g., energy stored in glucose, adenosine triphosphate [ATP], gasoline)
- define, compare and contrast scalar and vector quantities
- describe displacement and velocity quantitatively
- define acceleration, quantitatively, as a change in velocity during a time interval: a = Δv/Δt
- explain that, in the absence of resistive forces, motion at constant speed requires no energy input
- recall, from previous studies, the operational definition for force as a push or a pull, and for work as energy expended when the speed of an object is increased, or when an object is moved against the influence of an opposing force
- define gravitational potential energy as the work against gravity
- relate gravitational potential energy to work done using Ep = mgh and W = Fd and show that a change in energy is equal to work done on a system: W = ΔE
- quantify kinetic energy using Ek = 1/2 mv2 and relate this concept to energy conservation in transformations
(e.g., for an object falling a distance “h” from rest: mgh = Fd = 1/2 mv2)
- derive the SI unit of energy and work, the joule, from fundamental units
- investigate and analyze one-dimensional scalar motion and work done on an object or system, using algebraic and graphical techniques
(e.g., the relationships among distance, time and velocity; determining the area under the line in a force–distance graph)
- Apply the principles of energy conservation and thermodynamics to investigate, describe and predict efficiency of energy transformation in technological systems
- describe, qualitatively and in terms of thermodynamic laws, the energy transformations occurring in devices and systems
(e.g., automobile, bicycle coming to a stop, thermal power plant, food chain, refrigerator, heat pump, permafrost storage pits for food)
- describe how the first and second laws of thermodynamics have changed our understanding of energy conversions
(e.g., why heat engines are not 100% efficient)
- define, operationally, “useful” energy from a technological perspective, and analyze the stages of “useful” energy transformations in technological systems
(e.g., hydroelectric dam)
- recognize that there are limits to the amount of “useful” energy that can be derived from the conversion of potential energy to other forms in a technological device
(e.g., when the potential energy of gasoline is converted to kinetic energy in an automobile engine, some is also converted to heat; when electrical energy is converted to light energy in a light bulb, some is also converted to heat)
- explain, quantitatively, efficiency as a measure of the “useful” work compared to the total energy put into an energy conversion process or device
- apply concepts related to efficiency of thermal energy conversion to analyze the design of a thermal device
(e.g., heat pump, high efficiency furnace, automobile engine)
- compare the energy content of fuels used in thermal power plants in Alberta, in terms of costs, benefits, efficiency and sustainability
- explain the need for efficient energy conversions to protect our environment and to make judicious use of natural resources
(e.g., advancement in energy efficiency; Aboriginal perspectives on taking care of natural resources)
Skill Outcomes
(focus on problem solving)Initiating and Planning
Students will:Ask questions about observed relationships, and plan investigations of questions, ideas, problems and issues
- design an experiment, identifying and controlling major variables
(e.g., design an experiment involving a combustion reaction to demonstrate the conversion of chemical potential energy to thermal energy)
- formulate operational definitions of major variables
(e.g., predict or hypothesize the conversion of energy from potential form to kinetic form, in an experiment using a pendulum or free fall)
Performing and Recording
Students will:Conduct investigations into relationships between and among observable variables, and use a broad range of tools and techniques to gather and record data and information
- carry out procedures, controlling the major variables and adapting or extending procedures
(e.g., perform an experiment to demonstrate the equivalency of work done on an object and the resulting kinetic energy; design a device that converts mechanical energy into thermal energy)
- compile and organize data, using appropriate formats and data treatments to facilitate interpretation of the data
(e.g., use a computer-based laboratory to compile and organize data from an experiment to demonstrate the equivalency of work done on an object and the resulting kinetic energy)
- use library and electronic research tools to collect information on a given topic
(e.g., compile information on the energy content of fuels used in Alberta power plants; trace the flow of energy from the Sun to the lighting system in the school, identifying what changes are taking place at each stage of the process)
- select and integrate information from various print and electronic sources or from several parts of the same source
(e.g., create electronic documents, containing multiple links, on using alternative energy sources, such as wind or solar, to generate electricity in Alberta; relate the importance of the development of effective and efficient engines to the time of the Industrial Revolution and to present-day first-world economics)
Analyzing and Interpreting
Students will:Analyze data and apply mathematical and conceptual models to develop and assess possible solutions
- compile and display evidence and information, by hand or using technology, in a variety of formats, including diagrams, flow charts, tables, graphs and scatterplots
(e.g.,plot distance–time, velocity–time and force–distance graphs; manipulate and present data through the selection of appropriate tools, such as scientific instrumentation, calculators, databases or spreadsheets)
- identify limitations of data or measurement
(e.g., recognize that the measure of the local value of gravity varies globally; use significant digits appropriately)
- interpret patterns and trends in data, and infer or calculate linear and nonlinear relationships among variables
(e.g., interpret a graph of changing kinetic and potential energy from a pendulum during one-half of a period of oscillation; calculate the slope of the line in a distance–time graph; analyze a simple velocity–time graph to describe acceleration; calculate the area under the line in a force–distance graph)
- compare theoretical and empirical values and account for discrepancies
(e.g., determine the efficiency of thermal energy conversion systems)
- state a conclusion based on experimental data, and explain how evidence gathered supports or refutes the initial hypothesis
(e.g., explain the discrepancy between the theoretical and actual efficiency of a thermal energy conversion system)
- construct and test a prototype of a device or system, and troubleshoot problems as they arise
(e.g., design and build an energy conversion device)
- propose alternative solutions to a given practical problem, identify the potential strengths and weaknesses of each and select one as the basis for a plan
(e.g., assess whether coal or natural gas should be used to fuel thermal power plants in Alberta)
- evaluate a personally designed and constructed device on the basis of self-developed criteria
(e.g., evaluate an energy conversion device based on a modern or traditional design)
Communication and Teamwork
Students will:Work as members of a team in addressing problems, and apply the skills and conventions of science in communicating information and ideas and in assessing results
- represent large and small numbers using appropriate scientific notation
- select and use appropriate numeric, symbolic, graphical and linguistic modes of representation to communicate ideas, plans and results
(e.g., use appropriate Système international (SI) units, fundamental and derived units; use advanced menu features within a word processor to accomplish a task and to insert tables, graphs, text and graphics)work cooperatively with team members to develop and carry out a plan and to troubleshoot problems as they arise(e.g., develop a plan to build an energy conversion device, seek feedback, test and review the plan, make revisions, and implement the plan)
Attitude Outcomes
Interest in ScienceStudents will be encouraged to:
Show interest in science-related questions and issues, and pursue personal interests and career possibilities within science-related fields
(e.g., apply concepts learned in the classroom to everyday phenomena related to energy; show interest in a broad scope of science-related fields in which energy plays a significant role)
Mutual Respect
Students will be encouraged to:
Appreciate that scientific understanding evolves from the interaction of ideas involving people with different views and backgrounds
(e.g., appreciate Aboriginal technologies of the past and present that use locally-available materials and apply scientific principles; recognize that science and technology develop in response to global concerns, as well as to local needs)
Scientific Inquiry
Students will be encouraged to:
Seek and apply evidence when evaluating alternative approaches to investigations, problems and issues
(e.g., assess problem using a variety of criteria; respect alternative solutions; honestly evaluate limitations of their designs; be persistent in finding the best possible answer or solution to a question or problem)
Collaboration
Students will be encouraged to:
Work collaboratively in carrying out investigations and in generating and evaluating ideas
(e.g., select a variety of strategies, such as group brainstorming, active listening, paraphrasing and questioning, to find the best possible solution to a problem; work as a team member when assigning and performing tasks; accept responsibility for problems that arise)
Stewardship Students will be encouraged to:
Demonstrate sensitivity and responsibility in pursuing a balance between the needs of humans and a sustainable environment
(e.g., recognize that their choices and actions, and the choices and actions that technologists make, can have an impact on others and on the environment)
Safety Students will be encouraged to:
Show concern for safety in planning, carrying out and reviewing activities
(e.g., demonstrate concern for self and others in planning and carrying out experimental activities and the design of devices; select safe methods for collecting evidence and solving problems)
Links to Mathematics The following mathematics outcomes are related to the content of Unit B but are not considered prerequisites.
- Data Collection and Analysis - Grade 9 Mathematics, Statistics and Probability (Data Analysis), Specific Outcome 3
- Measurement and Unit Conversions - Mathematics 10C, Measurement,Specific Outcomes 1 and 2; Mathematics 10-3, Measurement, Specific Outcome 1; Mathematics 20-3, Algebra, Specific Outcome 3; Mathematics 30-3, Measurement, Specific Outcome 1
- Rate and Proportions - Grade 8 Mathematics, Number, Specific Outcomes 3 and 4; Mathematics 20-2, Measurement, Specific Outcome 1
- Graph Analysis - Grade 9 Mathematics, Patterns and Relations (Patterns), Specific Outcome 2; Mathematics10C, Relations and Functions, Specific Outcomes 1 and 4; Mathematics 20-3, Statistics, Specific Outcome 1
- Solving Equations - Grade 9 Mathematics, Patterns and Relations (Variables and Equations), Specific Outcome 3; Grade 9 Mathematics, Number, Specific Outcome 6;
- Slope - Mathematics10C, Relations and Functions, Specific Outcome 3 and 5; Mathematics 20-3, Algebra, Specific Outcome 2
- Powers - Mathematics10C, Algebra and Number, Specific Outcome 3
- Scale Diagrams - Mathematics 20-2, Measurement, Specific Outcome 2; Mathematics 20-3, Geometry, Specific Outcome 2
Unit Focus Questions
- Which came first: science or technology, and is it possible for technological development to take place without help from “pure” science
- How did effort to improve the efficiency of heat engines result in the formation of the first and second laws of thermodynamics?
- How can the analysis of moving objects help in the understanding of changes in kinetic energy, force, and work?
- Why are efficiency and sustainability important considerations in designing energy conversion technologies?
B3.0 Principles of energy conservation and thermodynamics can be used to describe the efficiency of energy transformations
Key Concepts
- Technological innovations of engines that led to the development of the concept of energy
- Design and function of technological systems and devices involving potential and kinetic energy, and thermal energy conversions
- Efficient use of energy, and environmental impact of inefficient use of energy
Learning Outcomes
- Describe how the first and second law of thermodynamics have changed our understanding of energy conversions
- Describe qualitatively, and in terms of thermodynamic laws, energy transformations in devices and systems
- Define, operationally, “useful” energy from a technological perspective, and analyze the stages of “useful” energy transformations in technological systems
- Recognize that there are limits to the amount of “useful” energy that can be derived from the conversion of potential energy to other forms in a technological device
- Identify the processes of trial and error that led to the invention of the engine, and relate the principles of thermodynamics to the development of more efficient engine designs
- Explain, quantitatively, efficiency as a measure of the “useful” work compared to the total energy put into an energy conversion process or device
- Apply concepts related to efficiency of thermal energy conversion to analyze the design of a thermal device
- Compare the energy content of fuels used in thermal power plants in Alberta (costs, benefits, efficiency, sustainability)
- Explain the need for efficient energy conversions to protect our environment and to make judicious use of natural resources
B3.1 Laws of Thermodynamics
Systems
System – a set of interconnected partsOpen system – exchanges both energy and matter with the surroundings
Closed system – exchanges energy with the surroundings but not matter.
Isolated system – does not exchange energy or matter with the surroundings.
The First Law of Thermodynamics
Energy cannot be created nor destroyed. It can only be changed from one form to another.The Perfect Machine Cannot be Achieved
Perfect machine – hypothetical machine in which all the input energy is converted completely into mechanical energy.Perpetual motion machine - A machine that will run forever without refueling
The Second Law of Thermodynamics
Heat (energy) always flows from hot objects (areas of high energy) to cold object (areas of low energy), never from cold objects to hot objects.Heat engine – device that converts heat energy into mechanical energy
Heat Engines and Heat Pumps
Heat pump – device that uses mechanical energy to transfer heat energy.
B3.2 The Development of Engine Technology
Developing a Technology
Technology (devices) does not appear out of nowhere. Normally somebody will develop a very basic prototype and different people will keep improving it over time.
Engines
Useful energy output – the energy taken out of the situation to do a specific task.
Lost energy is the part of the energy input that is changed into non-useful energy (heat due to friction)
For example out of 100 J worth of fuel that you put into a car, only 14 to 30 J is used to propel the car forward (useful energy) the remaining energy is lost as heat.
Ex. An SUV uses 2.5 × 108 J of fuel generate 1.1 × 108 J of kinetic energy. How efficient is the SUV?
Practice Problems
Practice Questions # 1- 3 on pages 216 – 217
B3.3 Check and Reflect p. 220
Applications 5 to 9
The Sun is a ball of superheated gases that undergo a fusion nuclear reaction to release light energy. When the light hits the Earth it is changed into several different types of energy.
Wind energy is caused by the uneven heating of Earth’s atmosphere. As sections warm up the air expands outwards causing wind.
Water energy is caused by the evaporation of water. The evaporated water rises up through the atmosphere and falls as precipitation. The rain hits the ground and flows downhill to the oceans. The river can be dammed and used to create hydro-electric energy.
Biomass energy is released when biological matter is combusted. Plants use the sunlight to growth by creating glucose (sugar). By burning the glucose in the biomass we can use the energy.
Non-Solar Energy Sources
Non-solar energy sources are not related to the Sun.
Geothermal energy is caused by the heat of Earth’s interior. Superheated water deep underground forces its way to the surface where it erupts as a geyser. Geothermal plants use the steam to create electricity.
Tidal energy is caused by the force of gravity of the moon on the Earth’s oceans. The oceans move towards the moon causing tides. The moving water can be used to create electrical energy.
Renewable and Non-renewable Energy Sources
Renewable energy sources are constantly being recreated. For example solar, wind, water, geothermal, tidal and biomass. For all practical implications these are unlimited sources. Non-renewable energy sources can only be used once. For example nuclear and fossil fuels. Once they are used, they are gone forever.
For example designing cars that run on solar power, using geothermal plants for heating and electricity.
Practice Problems
Do Review questions # 30 – 60 on pages 233-235
Engine Development Timeline
Developing Future Technologies
Technologies develop over time. What is science fiction today is tomorrow’s reality..
B3.3 Useful Energy and Efficiency
Useful energy
Energy input – the energy put into the situationUseful energy output – the energy taken out of the situation to do a specific task.
Lost energy is the part of the energy input that is changed into non-useful energy (heat due to friction)
For example out of 100 J worth of fuel that you put into a car, only 14 to 30 J is used to propel the car forward (useful energy) the remaining energy is lost as heat.
Efficiency
Efficiency - is a measure of how much of the input energy is changed into useful output energy.
Efficiency = Output Energy / Input Energy x 100%
Ex. An SUV uses 2.5 × 108 J of fuel generate 1.1 × 108 J of kinetic energy. How efficient is the SUV?
Efficiency = Output Energy / Input Energy x 100 %
Efficiency = 1.1 × 108 J / 2.5 × 108 J x 100 %
Efficiency = 44 %
Efficiency = 1.1 × 108 J / 2.5 × 108 J x 100 %
Efficiency = 44 %
| Efficiency = | Output Energy | × 100% | ||
| Input Energy | ||||
| Efficiency = | 1.1 × 108 J | × 100% | ||
| 2.5 × 108 J | ||||
| Efficiency = | 44 % | |||
Practice Problems
Practice Questions # 1- 3 on pages 216 – 217
B3.3 Check and Reflect p. 220
Applications 5 to 9
.
B3.4 Energy Applications
Energy Supply
Solar Energy SourcesThe Sun is a ball of superheated gases that undergo a fusion nuclear reaction to release light energy. When the light hits the Earth it is changed into several different types of energy.
Wind energy is caused by the uneven heating of Earth’s atmosphere. As sections warm up the air expands outwards causing wind.
Water energy is caused by the evaporation of water. The evaporated water rises up through the atmosphere and falls as precipitation. The rain hits the ground and flows downhill to the oceans. The river can be dammed and used to create hydro-electric energy.
Biomass energy is released when biological matter is combusted. Plants use the sunlight to growth by creating glucose (sugar). By burning the glucose in the biomass we can use the energy.
- Garbage
- Landfill gases
- Alcohol foods
- Crops
- Wood
Non-Solar Energy Sources
Non-solar energy sources are not related to the Sun.
Geothermal energy is caused by the heat of Earth’s interior. Superheated water deep underground forces its way to the surface where it erupts as a geyser. Geothermal plants use the steam to create electricity.
Tidal energy is caused by the force of gravity of the moon on the Earth’s oceans. The oceans move towards the moon causing tides. The moving water can be used to create electrical energy.
Renewable and Non-renewable Energy Sources
Renewable energy sources are constantly being recreated. For example solar, wind, water, geothermal, tidal and biomass. For all practical implications these are unlimited sources. Non-renewable energy sources can only be used once. For example nuclear and fossil fuels. Once they are used, they are gone forever.
Energy Demand
Energy demand has been increasing over time. Three factors have led to this:- Each person uses more energy today than people have used previously.
- The world’s population has been growing exponentially. See graph page 223. A few countries like China have imposed population restrictions.
- The world is heavily dependent on non-renewable energy sources. Alberta’s electricity is mostly powered by coal.
The Effects of Energy Use
The widespread use of fossil fuels has resulted in many problems- Greenhouse gases are released by burning fossil fuels.
- Smog is created by burning fossil fuels
- Oil tanker spills destroy marine habitats
- Oil drilling has environmental consequences.
Energy Consumption and Conservation
- Our supply of conventional oil is expected to last 40 years from 2000 which means in 2040 we will run out of oil. (estimated)
- Our supply of natural gas is expected to last 62 years from 2000, which means in 2060 we will run out of natural gas. (estimated)
- Both of these events will occur within your lifetime!
Sustainable Development and Planning for the Future
Sustainable development means continuing to improve living conditions but at a rate and using technology that will be viable forever.For example designing cars that run on solar power, using geothermal plants for heating and electricity.
Practice Problems
Do Review questions # 30 – 60 on pages 233-235
Program of Studies
Alberta Science 10
Program of Studies
Alberta Science 10
Program of Studies
Contact me:
BCHS Barrhead AB
Steven Montgomery
steven.montgomery@pembinahills.caBCHS Barrhead AB
Textbook
Addison Wesley Science 10 Textbook
Addison Wesley Science 10 Textbook