TIPS: Targeted Interventions for Proficiency in Science
Main Site »
Contact Us
Tips Home
Middle School »
High School »
Physical Science

Content Benchmark P.8.C.3
home / physical science / energy /

Physical Science
Force and Motion
Content Areas
Nature of Science (NOS)
Life Science
Earth Science
Physical Science

Students know physical, chemical, and nuclear changes involve a transfer of energy.  E/S

Energy Transfer
Matter undergoes physical, chemical and nuclear changes. What causes these changes to occur? Energy is the ability to do work and therefore the ability to make changes in matter. When a physical change occurs, work has been done on the matter to change the texture, shape, size, color, odor, volume, mass, weight, density or any other physical property of the matter. This energy can be transferred via different mechanism, such as heat, light, sound, mechanical motion, etc. Energy is transferred to the matter from some other source.

What is Energy?
Energy is involved in change and is transferred throughout systems. Energy is commonly defined as the ability to do work. People have learned how to change energy from one form to another so that we can do work more easily and live more comfortably.
Energy is transferred in many ways: heat, light, electricity, mechanical motion, sound, and nuclear and chemical transformations.

This Physics Classroom website gives a good summary of the basic concepts and terminology related to energy and is found at

Once on the site, click on “Work, Energy, and Power” in the left-hand menu bar.

The U.S. Department of Energy has a nicely organized website that charts different energy transformations, located at

In physical changes, as well as chemical and nuclear reactions, energy is transferred into or out of a system. Heat, light, mechanical motion, electricity or other energy transfer mechanism might all be involved in such transfers. However, the Law of Conservation of Energy applies to all physical, chemical, and nuclear changes, regardless of the mechanisms,
To learn more about the Conservation of Energy, please see the
MS TIPS benchmark P.8.C.4.

Units of Energy
The primary SI unit for energy is the Joule. It is equal to the amount of work required when 1N of force is applied for a distance of one meter (Nm).  An expenditure of one Joule per second is a Watt. Watts are the SI units for Power. A calorie is equal to the energy needed to heat one gram of water one degree centigrade. One calorie is equal to 4.184 Joules. The calories on food packaging are actually kilocalories. A BTU (British Thermal Unit) is the amount of heat necessary to raise one pound of water by 1 degree Fahrenheit (F).

To learn more about energy and its conversions please see

Energy in Physical Changes
Physical changes occur when objects undergoes a change that does not change their chemical nature. A physical change involves a change in physical properties. Physical properties can be observed without changing the type of matter. Examples of physical properties include: texture, shape, size, color, odor, volume, mass, weight, and density.

When a substance undergoes a physical change, an energy transfer occurs. Work is being done on the object to cause it to change. For example, when water is heated or cooled it undergoes a physical change. Kinetic energy of the particles within an object (sometimes called thermal energy) is either added or taken out of the water to cause it to change phase. As thermal energy is continuously added to the water, kinetic energy of the water molecules increases. Because temperature is the measurement of the average kinetic energy of the molecules, the temperature of the water also increases, as show in Figure 1.

Figure 1. An example of a heating curve showing the change in temperature over a period of time as energy is continuously added.

At two points in this Figure 1, the heating curve plateaus. When these plateaus occur, the added energy does not contribute to a change in temperature. Instead it causes a change in phase. This occurs at 0ºC when the water changes phase from solid to liquid or conversely, liquid to solid. It occurs again at 100ºC when it changes phase from liquid to gas or conversely, from gas to liquid.

More information about phase changes can be found in the
MS TIPS benchmark P.8.A.1

To learn more about physical changes, go to

Energy in Chemical Changes
In a chemical change, a substance undergoes a reaction in which the new substance (product) has different properties than the original substance (reactant(s)). All chemical reactions are accompanied by energy transformations. Some reactions release energy to their surroundings, usually in the form of heat transfer, and are called exothermic. On the other hand, some reactions have heat transferred from their surrounds to proceed. These reactions are called endothermic.

Good examples of exothermic and endothermic reactions can be seen in commercial instant hot and cold packs. Commercial packs usually consist of two compounds that when combined will release energy to its surroundings or absorb energy from its surroundings. Some hot packs consist of sodium acetate and air. When the sodium acetate is allowed to mix with the air, crystallization occurs and thermal energy within the pack increases, resulting in an increased temperature and the pack getting hotter. In a commercial instant cold pack, urea and ammonium chloride are held in separate containers within a plastic bag. When the bag is bent and the inside containers are broken, the two compounds mix together and begin to react. Because the reaction is endothermic, heat is transferred from the surrounding environment and the bag gets cold.
To learn more about chemical changes, go to

Energy in Nuclear Changes
A nuclear change involves changes in nuclear structure, such as fission (splitting) of a nucleus, or fusion (combining) of neutrons and protons to form heavier atoms. 

In nuclear fission reactions, an atom's nucleus splits into smaller parts, releasing a large amount of energy in the process. Nuclear fission is a process by which an atom’ nucleus is split by a neutron. This results in the formation of two or more new atoms that are smaller than the original atom. Most commonly this is done by "firing" a neutron at the nucleus of an atom. The energy of the neutron "bullet" causes the target element to split into two (or more) elements that are lighter than the parent atom.

fission reaction - The Fission Reaction of Uranium-235

The Fission Reaction of Uranium-235

Figure 2. This is an example of fission of U235 atom.
As the atom splits it releases energy and
transforms into new atomic structures (Sr90, Xe143 and 3 neutrons).
(Please note that Flash is required to see this figure animated)

During the fission of U-235, three neutrons are released in addition to the two progeny atoms. If these released neutrons collide with nearby U-235 nuclei, they can stimulate the fission of these atoms and start a self-sustaining nuclear chain reaction. This chain reaction is the basis of nuclear power. As uranium atoms continue to split, a significant amount of energy is released from the reaction. The heat transferred during this reaction is typically used to increase water temperature, creating steam, which can then be used to generate electrical energy.

Nuclear fusion reactions are reactions in which two or more elements "fuse" together to form one larger element, releasing energy in the process. A good example is the fusion of two "heavy" isotopes of hydrogen (deuterium: H-2 and tritium: H-3) into the element helium.

fusion reaction - <a href=Nuclear Fusion of Two Hydrogen Isotopes ">

Nuclear Fusion of Two Hydrogen Isotopes

Figure 3. This is an example of nuclear fusion in a
tokamak reastor. Deuterium and Tritium fuse.
As they fuse they release energy and become He4.
(Please note that Flash is required to see this figure animated)

Fusion reactions release tremendous amounts of energy and are commonly referred to as thermonuclear reactions.  Although many people think of the Sun as a large fireball, the Sun (and in fact all stars) are actually enormous fusion reactors. Stars are primarily gigantic balls of hydrogen gas under tremendous pressure due to gravitational forces.  Hydrogen molecules are fused into helium and heavier elements inside of stars, releasing energy that is transferred as light.  The tremendous mass of stars provides a large amount of gravitational potential energy which is needed to achieve nuclear fusion. The positively charged nuclei repel each other, and therefore, the nuclei strongly resist being forced together. When the interior of the star achieves tremendous temperatures (greater than 1 million Kelvin), they hydrogen nuclei can overcome this repulsion and get close enough for the attractive nuclear force to take over.

To learn more about nuclear changes, go to

back to top

Content Benchmark P.8.C.3

Students know physical, chemical, and nuclear changes involve a transfer of energy.  E/S

Common misconceptions associated with this benchmark

1. Students incorrectly believe that energy is truly lost in many energy transformations.

The Law of Conservation of Energy states that energy can be neither created nor destroyed. It can only be transferred (transformed). The total amount of energy in the universe remains constant. Students may believe that energy is used up the way that a battery is used up. Students cannot see the energy; therefore, they cannot see where it is being transferred to or how it is being transformed. The battery’s energy is transformed into other forms such as sound, heat and light, which do not disappear, but may not be noticeable to the student, especially if the battery is disconnected from a circuit. Ask students where the energy is going or how it is transformed. Also, having a diagram of energy flow might be useful in identifying student misconceptions.

The following website provides information about conservation of energy. In addition to explanations and mathematical formulas, it has simulations that demonstrate what happens to the energy as it is transformed.

2. Students incorrectly believe that energy is a “thing”, an object or something that is tangible.

Students view energy as a fuel or something that is stored, ready to use, and gets used up. The intent at this level is for students to improve their understanding of energy by experiencing many kinds of energy transfer. In such experiences, students may begin to understand that energy is not a substance to be used up. Fuel (such as oil or food) is a resouce that allows energy to be transformed when its chemical make up is changed. The chemical bonds contain potential energy that may be transferred to kinetic energy during combustion, which in turn, can be transferred (via work) to kinetic energy that allows pistons to move in an engine. The students only see the resource and the end result of work being done. Students must walk through the process of transformation to understand that the resource is not energy.

This following article offers a good insight into the student misconception that energy is a thing. It also offers a true/false quiz to help identify student misconceptions about energy.

3. Students are confused about the difference between conservation of energy and energy conservation.

Students often ask, “If energy is conserved, why are we running out of it?” Students have difficulty separating the idea that energy is transformed or transferred into a form that is no longer directly useful to power devices. Students also have difficulty with the concept that even though energy is conserved, it is no longer in a useful form. Increasingly, as we transform the energy from one type to another it becomes less and less useful. This concept is directly related to the Second Law of Thermodynamics.

For more information the Second Law of Thermodynamics go to

4. Students often think that nuclear reactions are the only way to get energy from particles.

A study was conducted at Kansas State University to find out what students’ misconceptions are about the atom. The majority of students correctly identified nuclear reactions, but most did not mention any other relationship between atoms and energy such as electromagnetic radiation, electricity, or chemical reactions. 

This following document addresses student misconceptions about nuclear energy. It is a lesson plan that asks the student to describe their ideas about nuclear energy, gives the teacher internet resources for addressing those concepts, and offers a test for pre and post content ideas.

To download the misconception information and lesson, go to

back to top

Content Benchmark P.8.C.3

Students know physical, chemical, and nuclear changes involve a transfer of energy.  E/S

Sample Test Questions

1st Item Specification: Recognize that in physical, chemical, and nuclear changes energy is transformed.

Depth Of Knowledge Level 1

  1. Below is a figure of a pendulum. The letters represents specific points that the pendulum passes through in its swing. Use this figure to answer the next question.


In a pendulum, the maximum potential energy is at what point in the swing?
  1. the bottom of the swing
  2. the top of the swing
  3. half way through the swing
  4. when the pendulum comes to a stop
  1. What best describes kinetic energy?
    1. The object is in motion.
    2. The object is at rest.
    3. The object can move
    4. The object cannot move.
  1. Which of the following is a transfer of chemical energy to thermal energy?
    1. A hairdryer is turned on to dry a girl’s hair.
    2. A boy eats an apple, which regulates his body temperature.
    3. An atom is split to increase the temperature of water
    4. An ice cube is placed in warm soup and melts.
  1. When solid ice has been changed into a liquid, energy has been transferred
    1. out of the ice to cause a chemical change.
    2. into the ice to cause a chemical change.
    3. into the ice to cause a physical change.
    4. out of the ice to cause a physical change.
  1. A student raised a book to place it on the shelf. In placing it on the shelf, which type of energy has been increased in the book?
    1. Chemical energy
    2. Potential energy
    3. Kinetic energy
    4. Thermal energy

Depth Of Knowledge Level 2

  1. This graph below shows the changes of state that occur as thermal energy is added to water.


Which of the following BEST describes what is occurring in the graph over time?

  1. The average molecular kinetic energy of the water is increasing.
  2. The average molecular kinetic energy of the water is decreasing.
  3. The average molecular kinetic energy of the water is unchanged.
  4. The average temperature of the water is unchanged.
  1. As shown in the image below, a milk and sugar mixture is located in an inner bag. The outer bag contains ice and salt. Use this image to answer the question below.


Two students are making ice cream. The milk and sugar mixture that will become the ice cream is located in a bag that is within another bag of ice and salt. The students shake the bag containing the ice and salt and the milk and sugar mixture within. Which answer BEST describes what is happening to energy in this process as the milk and sugar mixture begins to solidify?
  1. The energy from the ice is being transferred into the milk/sugar mixture.
  2. The energy in the milk/sugar mixture does not experience a change.
  3. The energy in the milk/sugar mixture is being transferred into the ice.
  4. The energy from your hands is being transferred into the milk/sugar mixture.
  1. Use this image of the heat pack below to answer the next question.


A basketball player activates a heat pack by punching it to break the plastic barrier that separates two chemicals. When the two chemicals are allowed to mix the bag becomes warm. Energy is transferred from the bag because of a
  1. physical change
  2. chemical change
  3. nuclear change
  4. pressure change
  1. Nuclear fusion occurs in the sun. During this process
    1. mass is converted into energy.
    2. energy is converted into mass.
    3. no energy is released.
    4. mass is unchanging.
  1. Sylvia accidentally leaves milk out on the counter on a hot summer day. At the end of the day, the milk smells bad. The milk has undergone a change because
    1. thermal energy is transferred to kinetic energy, so that the milk undergoes a physical change.
    2. chemical energy is transferred as bacteria use the milk for food, so that the milk undergoes a chemical change.
    3. nuclear energy is transferred into the milk as atoms decay causing the milk to heat and undergo chemical change.
    4. physical energy from the average motion of the milk’s molecules causes an increase in temperature.

Constructed Response P.8.C.3

    1. This picture shows the path that energy takes from the power plant to your home.


    1. Starting at the power plant, explain what form the energy is in. As the energy travels to the next location in the picture, explain how the energy is transformed. Continue explaining how energy is transformed until it reaches the end user (labeled “industrial use,” “commercial use,” and “home use”). Some transitions may contain more than one transformation.
    2. Will all of the energy from the power plant reach the end users?  Justify why or why not.

back to top

Content Benchmark P.8.C.3

Students know physical, chemical, and nuclear changes involve a transfer of energy. E/S

Answers to Sample Test Questions

  1. B, DOK level 1
  2. A, DOK level 1
  3. B, DOK level 1
  4. C, DOK level 1
  5. B, DOK level 1
  6. A, DOK level 1
  7. C, DOK level 2
  8. B, DOK level 2
  9. A, DOK level 2
  10. B, DOK level 2


Constructed Response 3-point Answer and Score Rubric:


3 points


Response addresses all parts of the question clearly and correctly.
Chemical energy from the coal, oil, or natural gas or nuclear energy from the uranium is transformed to heat energy. The heat energy boils water creating steam which flows with kinetic energy. The kinetic energy of the flowing steam turns the turbine. The turbines kinetic energy is transformed to electrical energy. The electrical energy is transferred along the power lines to the end users. At the end use location, the electrical energy is transferred to kinetic energy (for example, to run fans, computer hard drives, etc.), thermal energy (for example, in a floor heater, air conditioner), and/or light energy (for example, to make a light bulb glow). Not all of the energy will reach the end user because some of the energy will be transformed to thermal energy (e.g., friction in the turbine) that is not easily transformed into other energy forms.

2 points

Response addresses all parts of the question and includes only minor errors.

1 point

Response does not address all parts of the question.

0 points

Response is totally incorrect or no response provided.

back to top

Content Benchmark P.8.C.3

Students know physical, chemical, and nuclear changes involve a transfer of energy.  E/S

Intervention Strategies and Resources

The following is a list of intervention strategies and resources that will facilitate student understanding of this benchmark.

1. School Power….Naturally

Developed by the New York State Energy Research and Development authority, this website offers a variety of energy lesson plans. The lesson plans are complete with labs and activities and further resources. Lesson plans include: energy misconceptions quiz, fossil fuel dependence, the future of solar power, energy conversion games, energy resources, energy solutions, mechanical advantage, the absorption of solar energy, how photo cells work, electrical power, the refining of crude oil, nuclear fusion from the sun, the sun and the water cycle, pH, effect of acid rain, the carbon cycle and the greenhouse effect.

To access these activities, go to

2. Heat Transfer Lab: Ice Cream!

Developed by the University of Virginia Physics Department, this lab is an interesting way for students to look at energy transfers and its effect on matter. The website gives you a list of ingredients and procedures, typical questions relative to energy transfer, suggestions for inclusion, and an assessment.

This lab can be viewed at

3. Solar Cookout

Developed by the NEED Project, this is an excellent design for an inexpensive solar oven that can be used to teach students about solar energy transfer from the sun to the food. This design works well for cooking hot dogs or marshmallows. It incorporates the foil lined ‘Pringles’ cans. Time to cook is around 45 minutes on a sunny afternoon without additional insulation.

This activity can be downloaded at

4. Energy Quest Room

Developed by the California Energy Commission, this website includes projects, experiments, and descriptions of many types of energy. This website is highly interactive! It has short movies on energy as well as games and other interactive media. “The Story of Energy” includes information on the generation and transmission of electricity as well as biomass, geothermal, hydro, nuclear, ocean, solar and hydrogen energy sources. The website encourages conservation and gives students information on energy conservation in their home and community.

Go to this website by clicking on

back to top

Support Pages

Click Here
Sample Questions:
Click Here

Intervention Strategies & Resources:
Click Here

Benchmark Related Vocabulary

Chemical change
Energy transfer
Nuclear fission
Nuclear fusion
Physical change