9.2.3.2 Energy
Identify the energy forms and explain the transfers of energy involved in the operation of common devices.
For example: Light bulbs, electric motors, automobiles or bicycles.
Calculate and explain the energy, work and power involved in energy transfers in a mechanical system.
For example: Compare walking and running up or down steps.
Describe how energy is transferred through sound waves and how pitch and loudness are related to wave properties of frequency and amplitude.
Explain and calculate current, voltage and resistance, and describe energy transfers in simple electric circuits.
Describe how an electric current produces a magnetic force, and how this interaction is used in motors and electromagnets to produce mechanical energy.
Compare fission and fusion in terms of the reactants, the products and the conversion from matter into energy.
For example: The fusion of hydrogen produces energy in the sun.
Another example: The use of chain reactions in nuclear reactors.
Describe the properties and uses of forms of electromagnetic radiation from radio frequencies through gamma radiation.
For example: Compare the energy of microwaves and X-rays.
Overview
MN Standard in Lay Terms
Energy takes many forms and transfers within and between systems through many different ways, but the total energy of a system may always be accounted for and remains constant. Energy does not disappear and is either transferred to or stored in different forms.
Big Idea
Energy transfer is indeed a big idea. Everything we do is based on energy transfer. The more we know about it the more we develop new ideas. For example long ago scientists knew about Potential energy and kinetic energy and how it can be transferred between one another. A century ago Einstein's theory of relativity made it possible to learn about converting mass into energy and this paved the way for nuclear energy. Scientists are now struggling to transfer electricity without wires and this involves converting electrical energy into some other form for transfer and then to reconvert to electrical energy.
Scientists try to understand the physical universe by analyzing interactions between objects from the perspective of either forces between interacting objects or energy transferred between interacting objects. Focusing on energy transfer during an interaction is often a more fruitful way of thinking about these ideas for middle and high school students. Energy ideas can be applied to interactions, such as in mechanical interactions (applied, friction, drag, and elastic) and evidence-based explanations for changes in motion and motion energy can be developed. In addition, mechanical waves, light, sound and earthquakes can be studied from an interaction energy perspective. However, care must be taken since energy can be a mysterious concept and is frequently thought of as a substance with flow and conservation analogous to matter.
Many changes require a transfer of energy between a source and receiver. Different types of interactions may transfer different types of energy. For example mechanical, mechanical wave, magnetic and electrical interactions transfer mechanical energy, light interactions transfer light energy, and electric-circuit interactions transfer electrical energy. Nuclear reactions involve the particles of the nucleus and release enormous quantities of energy compared to chemical reactions.
Benchmarks for Science Literacy, AAAS-Project 2061 (1993)
National Science Education Standards, National Resource Council (1996).
MN Standard Benchmarks
9.2.3.2.1 Identify the energy forms and explain the transfers of energy involved in the operation of common devices. For example: Light bulbs, electric motors, automobiles or bicycles.
9.2.3.2.2 Calculate and explain the energy, work and power involved in energy transfers in a mechanical system. For example: Compare walking and running up or down steps.
9.2.3.2.3 Describe how energy is transferred through sound waves and how pitch and loudness are related to wave properties of frequency and amplitude.
9.2.3.2.4 Explain and calculate current, voltage and resistance, and describe energy transfers in simple electric circuits.
9.2.3.2.5 Describe how an electric current produces a magnetic force, and how this interaction is used in motors and electromagnets to produce mechanical energy.
9.2.3.2.6 Compare fission and fusion in terms of the reactants, the products and the conversion from matter into energy. For example: The fusion of hydrogen produces energy in the sun. Another example: The use of chain reactions in nuclear reactors.
9.2.3.2.7 Describe the properties and uses of forms of electromagnetic radiation from radio frequencies through gamma radiation. For example: Compare the energy of microwaves and X-rays.
The Essentials
For Fun and Discussion:
The Way Things Go film 1987 clips one two and three
Adam Sadowsky engineers a viral music video
The band "OK Go" dreamed up the idea of a massive Rube Goldberg machine for their next music video -- and Adam Sadowsky's team was charged with building it. He tells the story of the effort and engineering behind their labyrinthine creation that quickly became a YouTube sensation.
NSES Standards:
AAAS Benchmarks of Science Literacy and Atlas:
from Benchmarks Online - Project 2061 - AAAS (Physical Setting)
Structure of Matter (4D):
4D/H4 - The nucleus of radioactive isotopes is unstable and spontaneously decays, emitting particles and/or wavelike radiation. It cannot be predicted exactly when, if ever, an unstable nucleus will decay, but a large group of identical nuclei decay at a predictable rate. This predictability of decay rate allows radioactivity to be used for estimating the age of materials that contain radioactive substances.
Energy Transformations (4E):
4E/H1 - Although the various forms of energy appear very different, each can be measured in a way that makes it possible to keep track of how much of one form is converted into another. Whenever the amount of energy in one place diminishes, the amount in other places or forms increases by the same amount.
4E/H6 - Energy is released whenever the nuclei of very heavy atoms, such as uranium or plutonium, split into middleweight ones, or when very light nuclei, such as those of hydrogen and helium, combine into heavier ones. For a given quantity of a substance, the energy released in a nuclear reaction is very much greater than the energy given off in a chemical reaction.
4E/H7 - Electrical potential energy is associated with the separation of mutually attracting or repelling charges.
4E/H9 - Many forms of energy can be considered to be either kinetic energy, which is the energy of motion, or potential energy, which depends on the separation between mutually attracting or repelling objects.
4E/H10 - If no energy is transferred into or out of a system, the total energy of all the different forms in the system will not change, no matter what gradual or violent changes actually occur within the system.
Motion (4F):
4F/H3a - When electrically charged objects undergo a change in motion, they produce electromagnetic waves around them.
4F/H3c - In empty space, all electromagnetic waves move at the same speed-the "speed of light."
4F/H6c - The energy of waves (like any form of energy) can be changed into other forms of energy.
Forces of Nature (4G):
4G/H4ab - In many conducting materials, such as metals, some of the electrons are not firmly held by the nuclei of the atoms that make up the material. In these materials, applied electric forces can cause the electrons to move through the material, producing an electric current. In insulating materials, such as glass, the electrons are held more firmly, making it nearly impossible to produce an electric current in those materials.
4G/H5ab - Magnetic forces are very closely related to electric forces and are thought of as different aspects of a single electromagnetic force. Moving electrically charged objects produces magnetic forces and moving magnets produces electric forces.
4G/H5c - The interplay of electric and magnetic forces is the basis for many modern technologies, including electric motors, generators, and devices that produce or receive electromagnetic waves.
4G/H6 - The nuclear forces that hold the protons and neutrons in the nucleus of an atom together are much stronger than the electric forces between the protons and electrons of the atom. That is why much greater amounts of energy are released from nuclear reactions than from chemical reactions.
The Design World - Energy Sources and Use (8C):
8C/H7 - During any transformation of energy, there is inevitably some dissipation of energy into the environment. In this practical sense, energy gets "used up," even though it is still around somewhere.
THE BASICS:
NAEP
ENERGY
The topic "energy" is divided into two subtopics; one addresses the forms of energy and the other addresses energy transfer and conservation.4
Forms of Energy
Knowing the characteristics of familiar forms of energy (grade 4) and the scientific categories of potential and kinetic energy (grade 8) can lead to an understanding that, for the most part, the natural world can be explained and is predictable. The most basic characteristics of thermal, light, sound, electrical, and mechanical energy and the relationship between changes in the natural world and energy are included in the framework.5 For example, the fact that two objects, one at a higher temperature than the other, come to the same temperature when placed in contact with each other is a familiar experience. Heat as a concept can be used to explain this experience (grade 8). (9.2.3.2.1)
P8.8: Objects and substances in motion have kinetic energy. For example, a moving baseball can break a window; water flowing down a stream moves pebbles and floating objects along with it. (9.2.3.2.2) P8.9: Three forms of potential energy are gravitational, elastic, and chemical. Gravitational potential energy changes in a system as the relative positions of objects are changed. Objects can have elastic potential energy due to their compression, or chemical potential energy due to the nature and arrangement of the atoms. (9.2.3.2.1) P8.10: Energy is transferred from place to place. Light energy from the Sun travels through space to Earth (radiation). Thermal energy travels from a flame through the metal of a cooking pan to the water in the pan (conduction). Air warmed by a fireplace moves around a room (convection). Waves (including sound and seismic waves, waves on water, and light waves have energy and transfer energy when they interact with matter. (9.2.3.2.7) P8.11: A tiny fraction of the light energy from the Sun reaches Earth. Light energy from the Sun is Earth's primary source of energy, heating Earth surfaces and providing the energy that results in wind, ocean currents, and storms. (9.2.3.2.7) |
Energy Transfer and Conservation
The fact that energy is conserved can be demonstrated by keeping track of the familiar forms of energy as they are transferred from one object to another. The chemical potential energy in a battery is transferred by electric current to a light bulb, which in turn transfers the energy in the form of heat (thermal energy) and light to its surroundings (grade 4). The energy stored in the battery decreases as its surroundings are heated. The loss in chemical potential energy equals the light and heat (thermal energy) transferred by the bulb and the wires to their surroundings. Quantitative accounting is complex; however, on a qualitative basis, both the ability to trace energy transfer and the understanding that energy is conserved (grade 8) are of great explanatory and predictive value. Chemical reactions either release energy to the surroundings or cause energy to flow from the surroundings into the system (grade 12). The Sun as the main energy source for the Earth provides an opportunity at all grade levels to make important connections between the science disciplines. (9.2.3.2.1)
P8.12: When energy is transferred from one system to another, the quantity of energy before transfer equals the quantity of energy after transfer. For example, as an object falls, its potential energy decreases as its speed, and consequently, its kinetic energy increases. While an object is falling, some of the object's kinetic energy is transferred to the medium through which it falls, setting the medium into motion and heating it. (9.2.3.2.2) P8.13: Nuclear reactions take place in the Sun. In plants, light from the Sun is transferred to oxygen and carbon compounds, which, in combination, have chemical potential energy (photosynthesis). (9.2.3.2.6) |
Common Core Standards
Common Core Standards (i.e. connections with Math, Social Studies or Language Arts Standards):
Minnnesota Academic Math standards
(8.1.1.5) Express approximations of very large and very small numbers using scientific notation; understand how calculators display numbers in scientific notation. Multiply and divide numbers expressed in scientific notation, express the answer in scientific notation, using the correct number of significant digits when physical measurements are involved.
For example: (4.2×104)×(8.25×103) =3.465×108 , but if these numbers represent physical measurements, the answer should be expressed as 3.5×108 because the first factor, 4.2×104 , only has two significant digits.
(9.2.1.4) Obtain information and draw conclusions from graphs of functions and other relations.
Students can plot data of current and voltage to determine the resistance of a circuit.
(9.2.2.3) Sketch graphs of linear, quadratic and exponential functions, and translate between graphs, tables and symbolic representations. Know how to use graphing technology to graph these functions.
(9.3.1.3) Understand that quantities associated with physical measurements must be assigned units; apply such units correctly in expressions, equations and problem solutions that involve measurements; and convert between measurement systems.
For example: 60 miles/hour = 60 miles/hour × 5280 feet/mile × 1 hour/3600 seconds = 88 feet/second.
(9.3.1.5) Make reasonable estimates and judgments about the accuracy of values resulting from calculations involving measurements.
For example: Suppose the sides of a rectangle are measured to the nearest tenth of a centimeter at 2.6 cm and 9.8 cm. Because of measurement errors, the width could be as small as 2.55 cm or as large as 2.65 cm, with similar errors for the height. These errors affect calculations. For instance, the actual area of the rectangle could be smaller than 25 cm2 or larger than 26 cm2, even though 2.6 × 9.8 = 25.48.
(9.4.2.3) Design simple experiments and explain the impact of sampling methods, bias and the phrasing of questions asked during data collection.
2010 Minnesota Academic Standards - English Language Arts K-12
Curriculum and Assessment Alignment Form
Grades 9-10 Literacy in Science, and Technical Subjects
Minnesota Academic Standards: Language Arts
Anchor Standard Benchmark 1. Read closely to determine what the text says explicitly and to make logical inferences from it; cite specific textual evidence when writing or speaking to support conclusions drawn from the text. 1. Cite specific textual evidence to support analysis of science and technical texts, attending to the precise details of explanations or descriptions. 2. Determine central ideas or themes of a text and analyze their development; summarize the key supporting details and ideas. 2. Determine the central ideas or conclusions of a text; trace the text's explanation or depiction of a complex process, phenomenon, or concept; provide an accurate summary of the text. 3. Analyze how and why individuals, events, and ideas develop and interact over the course of a text. 3. Follow precisely a complex multistep procedure when carrying out experiments, designing solutions, taking measurements, or performing technical tasks, attending to special cases (constraints) or exceptions defined in the text. 4. Interpret words and phrases as they are used in a text, including determining technical, connotative, and figurative meanings, and analyze how specific word choices shape meaning or tone. 4. Determine the meaning of symbols, equations, graphical representations, tabular representations, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 9-10 texts and topics. 5. Analyze the structure of texts, including how specific sentences, paragraphs, and larger portions of the text (e.g., a section, chapter, scene, or stanza) relate to each other and the whole. 5. Analyze the structure of the relationships among concepts in a text, including relationships among key terms (e.g., force, friction, reaction force, energy). 6. Assess how point of view or purpose shapes the content and style of a text. 6. Analyze the author's purpose in describing phenomena, providing an explanation, describing a procedure, or discussing/reporting an experiment in a text, defining the question the author seeks to address. 7. Integrate and evaluate content presented in diverse media and formats, including visually and quantitatively, as well as in words. 7. Translate quantitative or technical information expressed in words in a text into visual form (e.g., a table or chart) and translate information expressed visually or mathematically (e.g., in an equation) into words. 8. Delineate and evaluate the argument and specific claims in a text, including the validity of the reasoning as well as the relevance and sufficiency of the evidence. 8. Assess the extent to which the reasoning and evidence in a text support the author's claim or a recommendation for solving a scientific or technical problem. 9. Analyze how two or more texts address similar themes or topics in order to build knowledge or to compare the approaches the authors take. 9. Compare and contrast findings presented in a text to those from other sources (including their own experiments), noting when the findings support or contradict previous explanations or accounts. 10. Read and comprehend complex literary and informational texts independently and proficiently. 10. By the end of grade 10, read and comprehend science/technical texts in the grades 9-10 text complexity band independently and proficiently.
Misconceptions
Hapkiewicz, A. (1999). Naïve Ideas in Earth Science. MSTA Journal, 44(2) (Fall'99), pp.26-30.
1. Energy is a thing. This is a fuzzy notion, probably because of the way that we talk about newton-meters or joules. It is difficult to imagine an amount of an abstraction.
2. The terms "energy" and "force" are interchangeable.
3. From the non-scientific point of view, "work" is synonymous with "labor". It is hard to convince someone that more work is probably being done playing football for one hour than studying an hour for a quiz.
4. An object at rest has no energy.
5. The only type of potential energy is gravitational.
6. Gravitational potential energy depends only on the height of an object.
7. Doubling the speed of a moving object doubles the kinetic energy.
8. Energy can be changed completely from one form to another (no energy losses).
9. Things "use up" energy.
10. Energy is confined to some particular origin, such as what we get from food or what the electric company sells.
11. Energy is truly lost in many energy transformations.
12. There is no relationship between matter and energy.
13. If energy is conserved, why are we running out of it?
14. Gamma rays, x-rays, ultraviolet light, visible light, infrared light, microwaves and radio waves are all very different entities.
15. Loudness and pitch of sounds are confused with each other.
16. The period of oscillation depends on the amplitude.
17. Waves transport matter.
18. There must be a medium for a wave to travel through.
19. Waves do not have energy.
20. All waves travel the same way.
21. Frequency is connected to loudness for all amplitudes.
22. Big waves travel faster than small waves in the same medium.
23. Different colors of light are different types of waves.
24. Pitch is related to intensity.
25. Light waves and radio waves are not the same thing.
26. Electrons move quickly (near the speed of light) through a circuit.
27. Current is the same thing as voltage.
28. There is no current between the terminals of a battery.
29. A circuit does not have form a closed loop for current to flow.
30. The bigger the battery, the more voltage.
31. Power and energy are the same thing.
32. A conductor has no resistance.
33. Generating electricity requires no work.
34. When generating electricity only the magnet can move.
35. Magnetic flux, rather than change of magnetic flux, causes an induced emf.
Vignette
(9.2.3.2.4)
Mr. S wanted to introduce a simple circuit, and the idea that current will not flow unless the circuit makes a closed loop. These understandings are needed before introducing Ohm's Law, and talking about electrical energy transfer. Mr. S starts by putting up the picture below:
Mr. S states, "Draw three different ways someone could light a light bulb with a C battery. Draw lines to represent wires. You can use up to 4 wires to complete your drawing." Students Draw three circuits in their science notebooks. After 3 to 5 minutes, the students share their drawings with the rest of their table group. Each group decides on three circuits they think will work, and draw them on a 3.5 ft by 2 ft white boards. Each group shares their circuits with class, stating why they think each circuit will light up. Mr. S does not comment on the students' circuits as each group presents.
After the groups have shared their circuits, Mr. S hands out one mini-light bulb, one C-size battery, and 4 wires to each pair of students. The students test their predictions and write down their findings in their science notebooks. Mr. S encourages them to come up with more than three ways to light the light bulb. When each groups exploration seems to die down, Mr. S introduces other materials that the students can use to try to make the light bulb light (paper clips, different types of coins, string, rubber stoppers, aluminum, different material nails, etc.).
At the end of class, Mr. S brings the class together to discuss what they found out. The important findings Mr. S wants to bring out in the discussion is that (1) a circuit needs to be a closed loop in order for the light bulb to light. (2) Certain metals allow the current to pass through them in order to light the light bulb. (3) The current has to pass through the filament of the light bulb to light, by connecting one end of the battery to the base of the light bulb and one end of the battery through the metal side of the light bulb. During the discussion, Mr. S introduces new vocabulary words; like open and closed circuits, potential difference (voltage), current (electron flow), and resistance (why light bulbs light).
The next day, Mr. S will introduce the students to the PhET simulation entitled Ohm's Law phet ohms-law. This simulation allows students to explore the relationship between voltage (batteries), resistance (light bulbs), and current (flow of electrons - brightens of bulbs).
Resources
Suggested Labs and Activities
The Physics Front
Physics First Conservation of Energy Units (9.2.3.2.1, 9.2.3.2.2)
Understanding the interconnectedness of the concepts of conservation of energy, momentum and angular momentum underpins the basis for much of physics. Units are not listed in a prescribed order.
Physics First Wave Energy Units (9.2.3.2.3)
Examples of all types of waves are found in nature. Our understanding of the physical world is not complete until we understand the properties and behaviors of waves. Mechanical waves require a material "medium" through which to travel, electromagnetic waves do not.
Physics First Electricity and Electrical Energy Units (9.2.3.2.4)
Electricity is a natural phenomenon that can be both invisible AND visible, both matter and energy, a type of wave made of protons or a force that cannot be seen. It can move at the speed of light... yet it vibrates in a cord without flowing at all. It can be weightless, or have a small weight. Flowing in a light bulb filament, it transforms into light, but is not used up. It can be stored in batteries. "Electricity" is not only a class of phenomena; it's a type of event.
Physics First Magnetism and Magnetic Force Units (9.2.3.2.5)
Magnetic fields can be defined as the regions surrounding a magnet where a moving electric charge will feel a force of attraction or repulsion. Invisible magnetic field lines emerge from the North pole of a magnet and enter the South pole. Field lines can be visualized by sprinkling small iron filings over a magnet covered by a clear sheet of plastic. When a compass (or any freely floating bar magnet) points north, it is actually aligning its north pole to the Earth's magnetic south pole.
Physics First Electromagnetism and Electromagnets Units (9.2.3.2.5)
An electromagnet works on the principle that an electric current not only allows electrons to flow in a circuit, but also generates a small magnetic field. When a wire carrying electricity is coiled, the magnetic field becomes even stronger. Iron or steel objects surrounded by this coiled electric wire also become magnetized. This combination of electronic energy, coiled wiring and conductive metal object forms the basis of an electromagnet.
ABC's of Nuclear Science (9.2.3.2.6)
published by the Lawrence Berkeley National Laboratory written by Victor Noto Produced by the Lawrence Berkeley National Laboratory, the ABC's of Nuclear Science site gives students a good general overview of nuclear science. Through descriptions and illustrations, students explore nuclear structure; radioactivity; alpha, beta, and gamma decay; half-life; reactions; fusion; fission; cosmic rays; and antimatter. Included is a comprehensive activity on how to build a cosmic ray detector with detailed lab manual and procedurals, plus nine shorter experiments on topics related to nuclear science.
Vernier Investigations:
Physical Science with Vernier:
Vernier technology is a source of data collection that allows students to accurately predict and analysis data. The links below are the complete labs as posted by Vernier Software and Technology.
Absorption of Radiant Energy (9.2.3.2) - Monitor temperature change due to radiant energy absorption. Calculate temperature changes. Interpret your results.
An Inclined Plane (9.2.3.2.2) - Use a Force Sensor to measure force. Calculate work and efficiency. Make conclusions using the results of the experiment.
Electromagnets: Winding Things Up (9.2.3.2.5) - Build an electromagnet. Measure magnetic field strength. Graph the results. Make conclusions about the relationship between number of wire winds and magnetic field strength.
Heat of Fusion (9.2.3.2.6) - Use a computer to make temperature measurements. and to analyze the data collected. Determine heat of fusion for ice (in J/g).
How Bright is the Light? (9.2.3.2.7) - Measure light intensity, graph and analyze data and make conclusions about the relationship between light intensity and distance.
Lead Storage Batteries (9.2.3.2.4) - Build a lead storage cell. Use an interface box to charge the cell. Measure the cell's voltage before and after use. Use the charged cell to power an electric motor. Make conclusions using the results of the experiment.
Lemon "Juice" (9.2.3.2.4) - Build several electrochemical cells. Use a computer to measure and display cell voltages. Discover which combinations produce a voltage. Decide which combination makes the "best" battery.
Magnetic Field Explorations (9.2.3.2.5) - Measure magnetic field strength. Graph and analyze data. Make conclusions about the relationship between magnetic field strength and distance. Measure and graph magnetic field strength at points along a bar magnet. Make conclusions about the magnetic field at various points on a bar magnet.
Reflectivity of Light (9.2.3.2.7) - Use a Light Sensor to measure reflected light. Calculate percent reflectivity of various colors. Make conclusions using the results of the experiment.
PASCO "Explorations in Physics"
Activity 10 - Conservation of Energy-GPE and KE (9.2.3.2.2)
PDF (584 KB) Investigate the relationship between the change in the gravitational potential energy and the kinetic energy of a falling object.
Activity 14 - What is Voltage? (9.2.3.2.4)
PDF (936 KB) Explore the difference between the voltage in series circuits and the voltage in parallel circuits.
Activity 15 - What is Current? (9.2.3.2.4)
PDF (932 KB) Explore the difference between the current in series circuits and the voltage in parallel circuits.
Activity 19 - Faraday's Law of Electromagnetic Induction (9.2.3.2.5)
PDF (616 KB) Measure the voltage across a coil of wire when a bar magnet moves through the coil of wire. Compare the voltage to the number of turns of wire in the coil
Activity 20 - Sound Wave Properties (9.2.3.2.3)
PDF (916 KB) Determine the frequency and wavelength of sound waves.
Activity 23 -Transfer of Energy-Radiation (9.2.3.2.1)
PDF (528 KB) Measure the change in temperature of equal amounts of water that have the same initial temperature, and are in two similar metal cans that have different surfaces. Determine which surface transfers thermal energy fastest.
University of Colorado PHeT Interactive Physics Simulations
Look inside a battery to see how it works. Select the battery voltage and little stick figures move charges from one end of the battery to the other. A voltmeter tells you the resulting battery voltage.
Radio waves and Electromagnetic Fields (Benchmark 9.2.3.2.7)
Broadcast radio waves from KPhET. Wiggle the transmitter electron manually or have it oscillate automatically. Display the field as a curve or vectors. The strip chart shows the electron positions at the transmitter and at the receiver.
Watch a string vibrate in slow motion. Wiggle the end of the string and make waves, or adjust the frequency and amplitude of an oscillator. Adjust the damping and tension. The end can be fixed, loose, or open.
Sound and Human Hearing (9.2.3.2.3)
This simulation lets you see sound waves. Adjust the frequency or volume and you can see and hear how the wave changes. Move the listener around and hear what she hears.
Start a chain reaction, or introduce non-radioactive isotopes to prevent one. Control energy production in a nuclear reactor! PhET
Circuit Construction Kit (DC Only) (9.2.3.2.4)
An electronics kit in your computer! Build circuits with resistors, light bulbs, batteries, and switches. Take measurements with the realistic ammeter and voltmeter. View the circuit as a schematic diagram, or switch to a life-like view
See how the equation form of Ohm's law relates to a simple circuit. Adjust the voltage and resistance, and see the current change according to Ohm's law. The sizes of the symbols in the equation change to match the circuit diagram. PhET
Battery-Resistor Circuit (9.2.3.2.4)
Look inside a resistor to see how it works. Increase the battery voltage to make more electrons flow though the resistor. Increase the resistance to block the flow of electrons. Watch the current and resistor temperature change. PhET
Magnets and Electromagnets (9.2.3.2.5)
Explore the interactions between a compass and bar magnet. Discover how you can use a battery and wire to make a magnet! Can you make it a stronger magnet? Can you make the magnetic field reverse? PhET
Generators (9.2.3.2.5)
Generate electricity with a bar magnet! Discover the physics behind the phenomena by exploring magnets and how you can use them to make a bulb light
Learn about conservation of energy with a skater dude! Build tracks, ramps and jumps for the skater and view the kinetic energy, potential energy and friction as he moves. You can also take the skater to different planets or even space!
A realistic mass and spring laboratory. Hang masses from springs and adjust the spring stiffness and damping. You can even slow time. Transport the lab to different planets. A chart shows the kinetic, potential, and thermal energy for each spring.
Blackbody Spectrum (9.2.3.2.7)
How does the blackbody spectrum of the sun compare to visible light? Learn about the blackbody spectrum of the sun, a light bulb, an oven, and the earth. Adjust the temperature to see the wavelength and intensity of the spectrum change. View the color of the peak of the spectral curve.
Microwaves (9.2.3.2.7)
How do microwaves heat up your coffee? Adjust the frequency and amplitude of microwaves. Watch water molecules rotating and bouncing around. View the microwave field as a wave, a single line of vectors, or the entire field.
Additional resources
ComPADRE is filling a stewardship role within the National Science Digital Library for the educational resources used by broad communities in physics and astronomy. This partnership of the American Association of Physics Teachers (AAPT), the American Astronomical Society (AAS), the American Institute of Physics/Society of Physics Students (AIP/SPS), and the American Physical Society (APS) helps teachers and learners find, and use, high quality resources through collections and services tailored to their specific needs.
Use your knowledge of physics to put these videos to the test!
Inspired by Rhett Allain's physics explanations at Dot Physics, Dan Meyer's blog series "What Can You Do With This?", and Dan's TEDx plea for a math curriculum makeover, I have been collecting video clips that are prime for my physics students to analyze.
Videos are categorized by topic to help teachers locate videos for the concepts at hand. Several videos are listed under multiple topics. The videos are presented without any further questions other than "Physics win or physics fail?" (real or fake?)
If you are looking around for some good labs to use or to tweek, check this site out. Items have been put here for physics teachers, by physics teachers, and range from first-year high school physics to AP material. The emphasis is on labs, but explanatory material is also available. The University sources on the bottom will direct you to even more great material. The collection of materials is growing all of the time.
Vocabulary/Glossary
Work: Work is done when force acting on a body displaces it. Work = Force component parallel to the displacement x Displacement. W=Fdcosθ
Net Work: Algebraic sum of the work done by all of the forces acting to displace an object.
Power: The rate of doing work. SI unit is the Watt= 1J/1s
Kinetic Energy: The energy an object has due to its motion, it is equal to ½ mv2, where m is the mass and v is the speed of the body.
Work Kinetic Energy Theorem: Net Work done on a body equals the change in its Kinetic Energy.
Potential Energy: The energy an object has due to its location in a force field.
Gravitational Potential Energy: The energy an object has due to its location in a Gravity field.
Elastic Potential Energy: The energy a spring possesses due its stretched or compressed position.
Energy Conversion: The transfer of energy between forms.
Conservative Force: A conservative force is a force with the property that the work done in moving a particle between two points is independent of the path taken such as gravity.
Non-Conservative Force: A conservative force is a force with the property that the work done in moving a particle between two points is independent of the path taken such as friction.
Conservation of Mechanical Energy: Mechanical energy is the kinetic energy plus all of the kinds of potential energy that are present. In the absence of non-conservative forces, mechanical energy is conserved meaning that remains constant within a system just changing forms.
Conservation of Energy: A principle stating that the total energy of an isolated system remains constant regardless of changes within the system.
(9.2.3.2.4,9.2.3.2.5)
Electron: A negatively charged particle that orbits the nucleus of the atom.
Proton: A positively charged particle that, along with the neutron, occupies the nucleus of the atom.
Coulomb: The unit measure of electrical charge. The smallest unit of charge is e=1.602 x 10-19 C
Conductor: A material that allows electrical charge to flow freely.
Insulator: A material that does not allow for the free flow of electrical charge.
Conduction: Transfer of electrical charge through a conductor.
Induction: Forced separation of electrical charge due to electric forces and fields.
Coulombs Law: The expression of electrical force expressing the forces direct proportionality as being proportional to each quantity of charge and inversely proportional to the square of the distance between them.
Electric Field
Electrical Potential or Voltage: The ability of an electric field to transfer energy to a quantity of charge, measured in volts. 1 volt has the ability to transfer 1 joule of energy to 1 coulomb of charge.
Electrical Current: The flow of electrical charge through a given cross sectional area, measured in amps. 1 amp = 1 coulomb of charge passing in 1 second.
Resistance: The flow of electrical charge is impeded by its interactions in a material resulting in a energy transfer to heating, measured in Ohm's.
Ohm's Law: The relationship between electrical potential, the flow of electrical current, and electrical resistance in a simple circuit. V=IR
Series Circuit: A circuit in which all elements have only one point in common so that the electrical current through each is the same and the overall resistance is the result of the addition of each resistive element.
Parallel Circuit: A circuit in which all elements have two points in common and the overall current in the circuit is the sum of the currents in all branches.
Motor: A device which converts electromagnetic energy to mechanical energy via the electromagnetic interaction.
Generator: A device that converts mechanical energy to electromagnetic energy via the electromagnetic interaction.
Transformer: A device which can step up or step down AC voltages and current via the electromagnetic interaction.
Restoring Force: The force that causes simple harmonic motion. The restoring force is always directed toward an object's equilibrium position.
Oscillation: A back-and-forth movement about an equilibrium position. Springs, pendulums, and other oscillators experience harmonic motion.
Simple Harmonic Motion: An object that moves about a stable equilibrium point and experiences a restoring force that is directly proportional to the oscillator's displacement.
Period: The time it takes a system to pass through one cycle of its repetitive motion. The period, T, is the inverse of the motion's frequency, f = 1/T.
Frequency: The number of cycles executed by a system in one second. Frequency is the inverse of period, f = 1/T. Frequency is measured in hertz, Hz.
Hertz: The units of frequency, defined as inverse-seconds (1 Hz = 1 s-1). "Hertz" can be used interchangeably with "cycles per second."
Amplitude: In reference to oscillation, amplitude is the maximum displacement of the oscillator from its equilibrium position. Amplitude tells how far an oscillator is swinging back and forth. In periodic motion, amplitude is the maximum displacement in each cycle of a system in periodic motion. The precise definition of amplitude depends on the particular situation: in the case of a stretched string it would be measured in meters, whereas for sound waves it would be measured in units of pressure.
Wavelength: The distance between successive wave crests, or troughs. Wavelength is measured in meters and is related to frequency and wave speed by = v/f.
Transverse Wave: Waves in which the medium moves in the direction perpendicular to the propagation of the wave. Waves on a stretched string, water waves, and electromagnetic waves are all examples of transverse waves.
Longitudinal Wave: Waves that oscillate in the same direction as the propagation of the wave. Sound is carried by longitudinal waves, since the air molecules move back and forth in the same direction the sound travels.
Sine Wave: Any oscillation, such as a sound wave or alternating current, whose waveform is that of a sine curve.
Medium: The substance that is displaced as a wave propagates through it. Air is the medium for sound waves, the string is the medium of transverse waves on a string, and water is the medium for ocean waves. Note that even if the waves in a given medium travel great distances, the medium itself remains more or less in the same place.
Wave Speed: The speed at which a wave crest or trough propagates. Note that this is not the speed at which the actual medium (like the stretched string or the air particles) moves.
Compression: An area of high air pressure that acts as the wave crest for sound waves. The spacing between successive compressions is the wavelength of sound, and the number of successive areas of compression that arrive at the ear per second is the frequency, or pitch, of the sound.
Rarefaction: An area of high air pressure that acts as the wave trough for sound waves. The spacing between successive rarefactions is the wavelength of sound, and the number of successive areas of rarefaction that arrive at the ear per second is the frequency, or pitch, of the sound.
Doppler Effect: Waves produced by a source that is moving with respect to the observer will seem to have a higher frequency and smaller wavelength if the motion is towards the observer, and a lower frequency and longer wavelength if the motion is away from the observer. The speed of the waves is independent of the motion of the source.
Bow Wave 2dim Shock Wave 3dim: Progressive disturbance propagated through a fluid such as water or air as the result of displacement by the foremost point of an object moving through it at a speed greater than the speed of a wave moving across the water.
Superposition Principle: The principle by which the displacements from different waves traveling in the same medium add up. Superposition is the basis for interference.
Wave Interference: The variation of wave amplitude that occurs when waves of the same or different frequency come together.
Reflection (Fixed and Free End): The phenomenon of light bouncing off a surface, such as a mirror.
Standing Wave: A wave that interferes with its own reflection so as to produce oscillations which stand still, rather than traveling down the length of the medium. Standing waves on a string with both ends tied down make up the harmonic series.
Natural Frequency: The frequency at which a system vibrates when set in free vibration.
Forced Vibration: The setting up of vibrations in an object by a vibrating force.
Resonance: The tendency of a system to oscillate with larger amplitude at some frequencies than at others.
Beats: When two waves of slightly different frequencies interfere with one another, they produce a "beating" interference pattern that alternates between constructive (in-phase) and destructive (out-of-phase). In the case of sound waves, this sort of interference makes a "wa-wa-wa" sound, and the frequency of the beats is equal to the difference in the frequencies of the two interfering waves.
Harmonics: The series of standing waves supported by a string with both ends tied down. The first member of the series, called the fundamental, has two nodes at the ends and one anti-node in the middle. The higher harmonics are generated by placing an integral number of nodes at even intervals over the length of the string. The harmonic series is very important in music.
Timbre: The combination of qualities of a sound that distinguishes it from other sounds of the same pitch and volume.
Nuclear Fission: A nuclear reaction in which the nucleus of an atom splits into smaller parts, such as lighter nuclei and often produces neutrons and photons gamma rays region of the electromagnetic spectrum, releasing a tremendous amount of energy.
Nuclear Fusion: The process by which two or more atomic nuclei join together, or "fuse" by either the strong or weak nuclear force depending on the mechanism, to form a single heavier nucleus.
The Electromagnetic Spectrum (9.2.3.2.7)
This unique NASA resource on the web, in print, and with companion videos introduces electromagnetic waves, their behaviors, and how scientists visualize these data. Each region of the spectrum is described and illustrated with engaging examples of NASA science. Come and explore the amazing world beyond the visible!
Web Based Instructional Videos:
The Annenburg Foundation's Science in Focus: Energy Video on Demand
NASA
Teachers' Domain: The Electromagnetic Spectrum: NASA published by the WGBH (9.2.3.2.7)
This item is a three-minute video segment from NASA for Grades 5-12 on the electromagnetic spectrum. It introduces the seven categories of the spectrum and explores how each type of radiation affects daily living. Complete with discussion questions and lesson.
Teachers' Domain is an NSF-funded pathway of the National Science Digital Library (NSDL). It is a growing collection of more than 1,000 free educational resources compiled by researchers and experienced teachers to promote the use of digital resources in the classroom.
HippoCampus is a project of the Monterey Institute for Technology and Education (MITE). The goal of HippoCampus is to provide high-quality, multimedia content on general education subjects to high school and college students free of charge. This site could be used in conjuction with your course to help teach the standards at various levels or support student learning outside the classroom.
Videos:
Work Energy and Power (9.2.3.2.2)
Electricity and Magnetism (9.2.3.2.4,9.2.3.2.5)
Assessment
Assessment of Students
Include questions designed to probe student understanding of concepts, both formative and summative. Identify taxonomic level of questions.
(9.2.3.2.2) 1. Two marbles, one twice as heavy as the other, are dropped to the ground from the roof of a building. Just before hitting the ground, the heavier marble has
A. as much kinetic energy as the lighter one.
B. twice as much kinetic energy as the lighter one.
C. half as much kinetic energy as the lighter one.
D. four times as much kinetic energy as the lighter one.
E. impossible to determine
Answers B
(9.2.3.2.2) 2. A block initially at rest is allowed to slide down a frictionless ramp and attains a speed v at the bottom.To achieve a speed 2v at the bottom, how many times as high must a new ramp be?
A. 1
B. 2
C. 3
D. 4
E. 5
F. 6
Answer D
(9.2.3.2.3) 3. By shaking one end of a stretched string, a single pulse is generated. The traveling pulse carries
A. energy.
B. momentum.
C. energy and momentum.
D. neither of the two
Answer A
(9.2.3.2.3) 4. Three observers,A,B, and C are listening to a moving source of sound. The diagram below shows the location of the wavecrests of the moving source with respect to the three observers. Which of the following is true?
A. The wavefronts move faster at A than at B and C.
B. The wavefronts move faster at C than at A and B.
C. The frequency of the sound is highest at A.
D. The frequency of the sound is highest at B.
E. The frequency of the sound is highest at C.
Answer E
(9.2.3.2.4) 5. Two light bulbs A and B are connected in series to a constant voltage source. When a wire is connected across B as shown, bulb A
A. burns more brightly.
B. burns as brightly.
C. burns more dimly.
D. goes out.
Answer A
(9.2.3.2.4) 6. The three light bulbs in the circuit all have the same resistance. Given that brightness is proportional to power dissipated, the brightness of bulbs B and C together, compared with the brightness of bulb A, is
A. twice as much.
B. the same.
C. half as much.
(9.2.3.2.7). The sun emits its greatest intensity of radiation in:
a. the visible portion of the spectrum
b. the infrared portion of the spectrum
c. the ultraviolet portion of the spectrum
d. the x-ray portion of the spectrum
Answer A
(9.2.3.2.7) 8. The Sun's rays are transmitted to Earth by means of
a. transmittance.
b. conduction of energy.
c. convection of particles from the.
d. electromagnetic radiation.
e. sound waves carrying energy
Answer D
(9.2.3.2.7) 9. What type of radiation most often associated with skin cancers?
a. Infrared
b. X-rays
c. Microwave
d. Visible green light
e. Ultraviolet
Answer E
(9.2.3.2.3) 10. Which one of the following travels the slowest?
a. Sound waves in water
b. Sound waves in steel
c. Visible radiation
d. Microwaves
e. Sound waves in air.
Answer E
(9.2.3.2.3) 11. A wave with a frequency of 5 Hz will have a period of ___________ second(s).
a. 0.1
b. 0.2
c. 0.5
d. 5.0
e. 10.0
Answer B
(9.2.3.2.3) 12. Which pair of frequencies could produce beats detectable by a person with normal hearing?
a. 300 Hz and 400 Hz
b. 1000 Hz and 2000 Hz
c. 300 Hz and 300 Hz
d. 500 Hz and 504 Hz
e. 20 Hz and 400 Hz
Answer D
(9.2.3.2.3) 13. Wave frequency is inversely proportional to
a. wave velocity.
b. wave speed.
c. amplitude.
d. period.
Answer D
(9.2.3.2.7) 14. Compared to visible radiation, infrared radiation in a vacuum
a. has shorter wavelengths and lower energy.
b. has longer wavelengths and lower energy.
c. has shorter wavelengths and faster speed.
d. has longer wavelengths and faster speed.
e. travels at a much lower speed than ultraviolet radiation
Answer B
(9.2.3.2.3) 15. One person talking loudly in a room is about 70 dB. If 1000 people in the room are all talking at the same level the intensity is now:
a. 80 dB
b. 90 dB
c. 100 dB
d. 120 dB
e. 170 dB
Answer C
(9.2.3.2.3) 16. What is the difference between longitudinal and transverse waves?
a. They are both the same type of waves
b. Transverse waves only occur with earthquakes
c. Longitudinal waves vibrate back and forth and transverse vibrate up and down
d. Transverse waves vibrate back and forth and longitudinal vibrate up and down
e. transverse waves travel the same speed in rock as longitudinal waves
Answer C
(9.2.3.2.3) 17. Compression sound waves can propagate through which of the following
a. gases only
b. liquids only
c. solids only
d. solids and gases only
e. solids and liquids only
f. liquids, solids, and gases
Answer F
(9.2.3.2.7) 18.. Which one of the following travels the fastest?
a. Sound waves in air.
b. Sonar
c. Microwave radiation.
d. Sounds waves produced by a sonic boom.
e. Ultrasonic waves
Answer C
(9.2.3.2.3) 19. An increase of 20 dB increases the sound intensity by a factor of
a. 10.
b. 20
c. 100.
d. 1000.
e. 10000.
Answer C
(9.2.3.2.3) 20. The property of a sound wave that is closely related to its loudness is
a. amplitude.
b. speed.
c. frequency.
d. wavelength.
e. color
Answer A
(9.2.3.2.3) 21.. A wave traveling in a medium has a speed of 10 m/s and a wavelength of 2.0 m. What is the frequency of the waves in the medium?
a. 0.2 Hz.
b. 0.5 Hz
c. 5.0 Hz.
d. 10.0 Hz.
e. 20.0 Hz.
Answer C
(9.2.3.2.4) 22. One ohm is a unit of
a. current.
b. voltage.
c. electric charge.
d. resistance.
e. power.
Answer D
(9.2.3.2.4) 23. Three different resistors: 10 ohm, 20 ohm, and 20 ohm are connected in series, the overall resistance is:
a. 5 ohms.
b. 10 ohms
c. 15 ohms
d. 20 ohms
e. 50 ohms
Answer E
(9.2.3.2.4) 24. Three different resistors: 10 ohm, 20 ohm, and 20 ohm are connected in parallel, the overall resistance is:
a. 5 ohms.
b. 10 ohms
c. 15 ohms
d. 20 ohms
e. 50 ohms
Answer A
(9.2.3.2.4) 25. A simple has a voltage of 5.0 V and a resistance of 1000 ohms. What is the current?
a. 1 mA
b. 5 mA
c. 10 mA
d. 25 mA
e. 1000 mA
Answer B
(9.2.3.2.5) 26. . What do you need to do with the magnet to get the lamp to light brightly?
a. Hold the magnet in the center of the coil
b. Hold the magnet as close as possible to the lamp itself?
c. Move the magnet up and down vertically slowly
d. Move the magnet left and right very quickly
e. By holding the magnet perpendicular to the wire coil.
Answer D
(9.2.3.2.4) 27. If the voltage across a resistor is cut in half from 4 volts to 2 volts, the current will
a. be doubled.
b. be quadrupled.
c. be cut in half.
d. remain the same
e. be impossible to know since we don't know the original current.
Answer C
(9.2.3.2.4) 28. One coulomb/second is a unit of
a. current.
b. voltage.
c. electric charge.
d. resistance.
e. power.
Answer A
(9.2.3.2.4) Questions 29 and 30: The figure at the top shows a single light in series with a battery of 10 volts.
29. What is the resistance for the light bulb?
a. 0 ohm
b. 0.1 ohm
c. 1 ohm
d. 2 ohm
e. 10 ohm
Answer E
30. What would be the current if a second lamp is connected as shown in the bottom figure?
a. 0 amp
b. 0.5 amp
c. 1 amp
d. 2 amp
e. 10 amp
Answer B
(9.2.3.2.4) 31. What type of circuit is the figure below?
a. A series circuit
b. A parallel circuit
c. A combination of parallel and series circuit
d. A double parallel circuit
Answer A
(9.2.3.2.4) 32. Which one of the following could a gamma ray penetrate?
a. Skin
b. paper
c. several sheets of paper
d. a thin piece of wood
e. it could penetrate all of the above
Answer E
(9.2.3.2.4) 33. The voltage across a resistor is 4 volts. If the voltage across a resistor is cut to 2 volts, the resistance will
a. be doubled.
b. be quadrupled.
c. be cut in half.
d. be cut to one-fourth.
e. remain the same.
Answer E
(9.2.3.2.5) 34. An ac voltage can be easily increased or decreased using a
a. generator.
b. motor.
c. transformer.
d. fuse.
e. battery.
Answer C
(9.2.3.2.5) 35. Which one the following can produce a magnetic field?
a. A moving piece of plastic
b. A moving electric charge.
c. A stationary negative electric charge
d. A stationary positive electric charge.
Answer B
(9.2.3.2.6) 36. During the normal process of radioactive decay a U-235 atom takes how long on average to split?
a. 700,000,000 years
b. 4,200,000,000 years
c. 200 days
d. 3 hours
e. 1 billionth of a sec
Answer A
(9.2.3.2.6) 37. During the process of fission a U-235 atom takes how long on average to split?
a. 700,000,000 years
b. 4,200,000,000 years
c. 200 days
d. 3 hours
e. 1 billionth of a sec
Answer E
(9.2.3.2.6) 38. The minimum amount of U-235 necessary to sustain a fission chain reaction is
a. 100 atoms.
b. 100,000,000 atoms.
c. 3 mg.
d. 0.3 g.
e. 2 kg.
Answer E
(9.2.3.2.6) 39. The process that will enable the Sun to burn for an estimated 10 billion years is:
a. Gravitational contraction of the Sun.
b. The fact that the Sun burns like a big lump of coal.
c. The fusion of hydrogen to produce helium and energy.
d. The fission process of uranium at the core of the Sun to produce energy.
e. Completely unknown to scientists since we cannot directly observe the core of the Sun.
Answer C
(9.2.3.2.6) 40. Stars like the Sun are composed of plasma containing mostly nuclei of the elements
a. helium and oxygen
b. hydrogen and helium.
c. hydrogen and oxygen.
d. hydrogen and carbon.
e. carbon and oxygen.
Answer B
Assessment of Teachers
Modeling Instruction in High School Physics, Chemistry, Physical Science, and Biology
Materials and readings for teacher discussion and use for professional development
The Modeling Method of High School Physics Instruction has been under development at Arizona State University since 1990 under the leadership of David Hestenes, Professor of Physics. The program cultivates physics teachers as school experts on effective use of guided inquiry in science teaching, thereby providing schools and school districts with a valuable resource for broader reform. Program goals are fully aligned with National Science Education Standards. The Modeling Method corrects many weaknesses of the traditional lecture-demonstration method, including fragmentation of knowledge, student passivity, and persistence of naive beliefs about the physical world. Unlike the traditional approach, in which students wade through an endless stream of seemingly unrelated topics, the Modeling Method organizes the course around a small number of scientific models, thus making the course coherent. In 2000 the program was extended to physical science and in 2005 to chemistry, by demand of committed teachers.
Peer Instruction: A User's Manual, (Mazur, Eric, Harvard University, Prentice Hall, 1997) - strategies and conceptual questions for using Student Response Systems and professional development.
Differentiation
Strategies from The Inclusive Classroom: Teaching Mathematics and Science to English-Language Learners, (Jarrett, Denise, Northwest Regional Educational Laboratory, Nov. 1999)
Thematic Instruction: Theme-based units can help ELL students connect prior knowledge to language and real-world applications.
Cooperative Learning: Students use language related to task, while conversing and tutoring one another.
Inquiry and Problem Solving: Inquiry and problem solving can be used prior to proficiency in English. Inquiry approaches in science can help student's language acquisition as well as their content knowledge.
Vocabulary Development: Students learn the meaning of words best during investigations and activities, instead of as a vocabulary list.
Modify Speech: Teachers can help ELL students by using an active voice, limiting new terms, using visual support, and paraphrasing or repeating difficult concepts. Slowing down speech, speaking clearly, and using a simple language structure will help ELL students with understanding.
Make ELL Students Feel Welcome: Encourage ELL students to express ideas, thought, and experiences. Focus on what student is say, not how they say it.
Article: PER research techniques for the multicultural classroom
Parents/Admin
Administrators
If observing a lesson on this standard what might they expect to see.
Ideas adapted from Best Practice: Today's Standards for Teaching and Learning in America's Schools (Daniels, H, Hyde, A, and Zemelman, S, Heinemann, Portsmouth, NH, 2005).
1) Students being challenged in thinking how energy can be transformed within a system or transferred to other systems or the environment, but is always conserved.
2) Students testing their understanding of mechanical, electrical, waves, and electromagnet energy transfer and energy conservation through investigations or solving real life scenarios using the concepts and associated equations.
3) Students taking on responsibility for their own learning.
4) Student working in collaborative groups, analyzing, synthesizing, and defending conclusions.
5) Students sharing explanations for results of investigation and understanding of concepts.
6) Students continuously assessing and being assessed on their understanding of energy transfer and energy conservation.
7) Students concepts are being built on prior knowledge of energy.