Key Idea: Energy can be transferred from one system to another (or from a system to its environment) in different ways: by conduction, mechanically, electrically, or by radiation (electromagnetic waves).

Students are expected to know that:

  1. Thermal energy can be transferred by conduction when a warmer object (including liquids, like water, and gases, like air) is in contact with a cooler one. [Note: this is not the only way thermal energy can be transferred. See boundary statement 3.]
    1. Two objects must be in contact with each other for thermal energy to be transferred by conduction (which is not the case for radiation). This means that the sun does not transfer thermal energy directly to the earth.
    2. There must be a temperature difference between the objects in contact for thermal energy to be transferred by conduction. The greater the temperature difference the greater the amount of thermal energy that can be transferred by conduction (assuming the mass or type of material is held constant).
    3. The thermal energy transferred by conduction goes from the warmer object to the cooler one.
    4. As thermal energy is transferred by conduction the thermal energy (and temperature) of the cooler object will increase and the thermal energy (and temperature) of the warmer object will decrease until the objects are at the same temperature. [This sub-idea assumes that neither object changes state, in which case the temperature of the object would not increase or decrease as the change of state was occurring. Assessment items are limited to contexts in which there is no change of state.]
  2. Energy can be transferred mechanically when one object pushes or pulls on another object over a distance.
    1. In order for energy to be transferred mechanically there must be a change in position and/or shape (the push or pull must act over a distance).  This energy transfer will stop if the motion/changing of position stops. 
    2. Energy will be transferred mechanically the entire time the push or pull is acting (in the direction of motion) and energy transfer will stop when the push or pull stops.
    3. When two pushes or pulls act over the same distance, the stronger push or pull transfers more energy mechanically than the weaker push or pull.
  3. Energy can be transferred electrically when an electrical source, such as a battery or generator, is connected in a complete circuit to an electrical device, such as a light bulb, speaker, heater, or motor.
  4. Energy can be transferred by electromagnetic radiation.
    1. Electromagnetic radiation is always given off by all objects and energy is transferred when this electromagnetic radiation is absorbed by another object.
    2. Electromagnetic radiation can transfer energy through space; therefore, objects do not need to be in contact with each other in order to transfer energy by radiation.
    3. The amount of electromagnetic radiation given off by an object can depend on the temperature of the object. The higher the temperature of an object, the more electromagnetic radiation the object gives off.
    4. When energy is transferred to an object by radiation, the temperature and thermal energy of the object typically increase.  When energy is transferred from an object by radiation, the temperature and thermal energy of the object typically decrease. [This sub-idea assumes that neither object changes state, in which case the temperature of the object would not increase or decrease. Assessment items are limited to contexts in which there is no change of state.]
    5. This is the mechanism by which the sun transfers energy to the earth.
  5. Students should know that as energy is transferred from one system to another, energy transformations can also occur.

Boundaries:

  1. Examples of mechanical energy transfer that students should be familiar with include the energy transfer that occurs when billiard balls hit each other, when a ball is thrown or kicked, when a baseball or golf ball is hit with a bat or club, when an object is set in motion by a rubber band or spring, or when a bobsled or swing is pushed. Assessment items should use contexts in which it is clear that the object supplying the energy has less energy after the transfer and the object receiving the energy has more energy after the transfer. For example, when a ball is thrown, it may be hard to appreciate that your body is loosing energy. Note that this may also be true for other forms of transfer. For example, it may not be obvious that an object that radiates energy loses energy.
  2. Students are not expected to know that conduction occurs through collisions of atoms.
  3. Students are not expected to know that convection and diffusion are other ways by which thermal energy is transferred.
  4. Although students are expected to know that when energy is transferred, a decrease of energy somewhere is accompanied by an increase in energy somewhere else and vice versa, they are not expected to know that the total amount of energy in the system is conserved.
  5. Students are not expected to keep track of how much energy is transferred by each mechanism.
Percent of students answering correctly (click on the item ID number to view the item and additional data)
Item ID
Number
Knowledge Being Assessed Grades
6–8
Grades
9–12
Select This Item for My Item Bank

NG034003

The thermal energy of a toy bear in the sunlight will be greater than the thermal energy of an identical bear in the shade because more energy is transferred directly from the sun to the bear in the sunlight than to the bear in the shade.

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NG059002

Energy is transferred when a battery is used to power a cell phone, and energy is transferred when the sun shines on a plant.

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NG055002

Energy is transferred when a battery is connected to a light bulb in a complete circuit, and energy is transferred when wind causes a windmill to rotate.

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NG060002

Energy is transferred when a waterfall is used to turn a wheel, and energy is transferred when a fire in a fireplace is used to heat a room.

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NG025003

While a student holds a cold piece of metal in her hand, the metal will get warmer because thermal energy is transferred from the student's hand to the metal.

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NG062002

A hot cookie will transfer more thermal energy to a cold plate than a cookie that is at room temperature because the temperature difference between the hot cookie and the cold plate is greater than the temperature difference between the cookie at room temperature and the cold plate.

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NG056004

Energy is transferred when a cold spoon is placed in a cup of hot tea, and energy is transferred when an ice cube is placed in a cup of hot tea.

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NG056003

Energy is transferred when a cold spoon is placed in a cup of hot tea, and energy is transferred when a spring is used to roll a ball across the floor.

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NG047003

When a ball that is 50ºF is placed in a bucket of water that is 80ºF, thermal energy is transferred from the water to the ball until they are both the same temperature.

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NG064002

Energy is transferred from the sun to a tree as light that is radiated from the sun is absorbed by the tree.

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NG032003

A girl feels warmer when she is in the sun than when she is in the shade under a tree because energy is being transferred directly from the sun to the girl.

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NG056002

Energy is transferred when an ice cube is placed in a cup of hot tea, and energy is transferred when a spring is used to roll a ball across the floor.

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NG054002

Energy is transferred electrically from a power plant to a light bulb in a lamp only when the lamp is turned on because energy can be transferred electrically only when there is a complete circuit.

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NG033003

A girl feels warmer when she is in the sunlight than when she is in the shade under an umbrella because energy is being transferred directly from the sun to the girl when she is in the sunlight.

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NG057002

Energy is transferred when a person touches a cold piece of metal, and energy is transferred when a lamp shines light on a table.

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NG061002

When cold butter is placed on top of hot corn, thermal energy is transferred from the corn to the butter but not from the butter to the corn.

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NG049003

When a spring is used to shoot a cart across the floor, the spring transfers energy to the cart. (This item uses bar graphs to illustrate the amount of elastic energy the spring has and the amount of motion energy the cart has as the cart is rolling across the floor.)

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NG047004

When a ball that is 80ºF is placed in a bucket of water that is 50ºF, thermal energy is transferred from the ball to the water until they are both at the same temperature.

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NG035002

The heating coils on an electric stove give off energy in the form of electromagnetic radiation at all temperatures, not just when they are hot.

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NG031003

If a hot frying pan is placed on the counter, after a while the frying pan, the counter, and the air will be at the same temperature because thermal energy will be transferred from the frying pan to the counter and from the frying pan to the air.

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NG027002

When a cold object is in contact with a warm object, thermal energy is transferred from the warm object to the cold object.

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NG101001

When a warm can of soda is in contact with cold water, thermal energy is transferred from the can of soda to the water so the can of soda gets cooler and the water gets warmer.

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NG058002

Energy is transferred when a person comes in contact with cold air, and energy is transferred when an electric generator is used to run a motor.

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NG023002

When cold water is poured into a cup that is at room temperature, thermal energy is transferred from the cup to the water until they are both at the same temperature.

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NG022003

When water that is 40ºF is poured into a cup that is 70ºF, thermal energy is transferred from the cup to the water until they reach the same temperature.

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NG045002

Both a light bulb and an ice cream cone radiate energy because all objects radiate energy.

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Frequency of selecting a misconception

Misconception
ID Number

Student Misconception

Grades
6–8
Grades
9–12

NGM067

Energy is spontaneously transferred out of colder regions or objects and into hotter ones.

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NGM066

When objects are in contact an equal amount of energy is transferred between them, this causes no change in temperature (AAAS Project 2061, 2017).

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NGM057

Energy is not transferred from one object to another unless those objects are in direct contact with each other (AAAS Project 2061, n.d.).

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NGM056

Electrical sources such as batteries transfer energy all the time, even when there is not a complete circuit (AAAS Project 2061, n.d.).

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NGM054

Only hot or warm objects transfer thermal energy (AAAS Project 2061, n.d.).

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NGM036

Only the sun transfers energy in the form of electromagnetic radiation (AAAS Project 2061, n.d.).

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NGM032

Only hot objects can transfer energy in the form of electromagnetic radiation (AAAS Project 2061, n.d.).

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NGM031

Only objects that are glowing can transfer energy in the form of electromagnetic radiation (AAAS Project 2061, n.d.).

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NGM016

When two objects at different temperatures are in contact with each other, thermal energy is transferred from the warmer object to the cooler object and “coldness” or ”cold energy” is transferred from the cooler object to the warmer object (AAAS Project 2061, n.d.).

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NGM015

When a cold and a warm object are placed in contact with each other, the warm object gets colder and the cold object gets warmer because “coldness” is transferred from one object to the other (Brook, Briggs, Bell, & Driver, 1984; Newell & Ross, 1996).

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NGM013

Thermal energy will continue to be transferred by conduction even after objects in contact with each other reach the same temperature; the temperature of the object getting warmer will continue to increase and the temperature of the object getting cooler will continue to decrease (Kesidou & Duit, 1993).

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NGM010

Energy can be created (Kruger, 1990; Lovrude, 2004; Papadouris et al., 2008).

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EGM035

Springs or other elastic objects have the same amount of elastic energy regardless of how much they are stretched or compressed (AAAS Project 2061, n.d.).

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Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.