Key Idea: Regardless of what happens within a system, the total amount of energy in the system remains the same unless energy is added to or released from the system.
Students should know that:
- Even though the forms of energy
present within a system may change, the total amount of energy in the system remains the same unless energy is added to or released from the system.
- If the total amount of energy in a
system decreases or increases, an equal amount of energy must have gone to or come from somewhere outside the system.
- If no energy enters or leaves a
system, a decrease of one form of energy by a certain amount within the system must be balanced by an increase of another form of energy by that same amount within
the system (or a net increase of multiple forms of energy by that same amount). Similarly, an increase of one form of energy by a certain amount within a
system must be balanced by a decrease of another form of energy by that same amount within the system (or a net decrease of multiple forms of energy by that same
amount).
- Energy can neither be created nor
destroyed but it can be transferred and/or transformed within and between systems.
- If energy is transferred to or
from a very large system (or a very complex system), increases or decreases of energy may be difficult to detect and, therefore, it may appear that energy was not
conserved.
Boundaries:
-
Assessment items avoid using the phrase “energy conservation” or “conservation of energy” because students often associate these terms
with efforts to conserve energy resources.
-
Assessment items do not ask students to make calculations about the amount of energy in a system or about changes in energy.
-
Students are not expected to know about energy-mass conversions such as nuclear reactions or other subatomic interactions.
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
4–5 |
Grades
6–8 |
Grades
9–12 |
Select This Item for My Item Bank |
NG071003
|
Assuming that no energy is transferred between a ball and the curved track it is moving in, or between the ball and the air around it, the ball will move down the track and then up to a point equal to the height from which it started.
| 55% | 52% |
61% | 
|
NG083004
|
Energy is transferred to the air around hot food as the food cools even though the temperature of the air does not appear to increase.
| 56% | 47% |
50% | |
NG075004
|
Assuming that no energy is transferred between a ball and the curved track it is moving in, or between the ball and the air around it, a ball on a curved track will reach a point as high as the point from which it started because as the ball moves down the track, its gravitational potential energy will change into motion energy, and as the ball goes up the other side, its motion energy will be changed back into an equal amount of gravitational potential energy.
| 39% | 41% |
51% | |
NG076004
|
The total amount of energy in a system remains the same unless energy enters or leaves the system.
| N/A | 34% |
46% | |
NG085003
|
Assuming that no energy is transferred between a ball and the curved track it is moving in, or between the ball and the air around it, the ball will not have enough energy to go over a hill that is higher than the height from which it started because the total energy of the system has to remain the same.
| N/A | 31% |
43% | |
NG070003
|
Assuming that no energy is transferred between a ball and the curved track it is moving in, or between the ball and the air around it, the ball will move to a height equal to the height from which it started.
| 27% | 34% |
44% | |
NG088004
|
When a student shoots a rubber band across the room, the elastic energy of the rubber band is transformed into motion energy, and the total amount of energy stays the same. (This item uses bar graphs to depict the amount of each kind of energy.)
| 27% | 30% |
41% | |
NG081004
|
The total energy inside a closed cooler filled with ice and a can of soda stays the same even though the can of soda gets colder, because the amount of energy that the can of soda lost is equal to the amount of energy that the ice gained.
| N/A | 26% |
41% | |
NG082004
|
When an apple falls from a tree, the apple has less energy when it is on the ground that it did when it was on the tree.
| 36% | 28% |
35% | |
NG089004
|
The total amount of energy in a lunch box containing only an ice pack and the air around it remains the same even after the ice pack gets warmer and the air gets colder. (This item uses bar graphs to depict the amounts of each form of energy.)
| N/A | 27% |
32% | |
NG080004
|
As a clay ball falls and hits the ground, the total amount of energy in the system stays the same because the decrease in energy due to the clay ball moving closer to the ground is equal to the increase in energy due to the clay ball and the floor getting warmer.
| N/A | 22% |
34% | |
NG096003
|
The total amount of energy a ball has does not change after it goes down and up a dip because the total energy of the system (ball and track) does not change (assuming no energy transfer between the ball and the track and the ball and the air around it).
| N/A | 21% |
32% | |
NG087004
|
A roller skater, who coasts down one hill and up another hill that is the same height as the first hill, will not have enough energy to reach the top of the second hill because some of her motion energy is transformed into thermal energy.
| N/A | 23% |
29% | |
NG095003
|
The total amount of energy a ball has does not change after it goes down and up a dip because the total energy of the system (ball and track) does not change (assuming no energy transfer between the ball and the track and the ball and the air around it).
| N/A | 23% |
27% | |
NG078003
|
After a rubber band is used to shoot a toy car across the floor, the total energy of the system will remain the same because the increase in the motion energy (kinetic energy) of the car is the same as the decrease in the elastic energy of the rubber band.
| N/A | 18% |
31% | |
NG068006
|
If a book falls off a shelf, the amount of energy the book has when it is on the floor is less than the amount of energy it had when it was on the shelf because the amount of energy of the floor has increased, and if energy increases in one part of a system, it must decrease in another.
| 32% | 21% |
26% | |
NG093003
|
Assuming no energy transfer between a ball and the track it is moving in, the amount of energy the ball has after it goes over a hill will be the same as before it went over the hill because the total amount of energy in the system did not change.
| N/A | 19% |
29% | |
NG074004
|
Assuming that no energy is transferred between a ball and the curved track it is moving in, or between the ball and the air around it, the ball will move to a height equal to the height from which it started.
| N/A | 22% |
24% | |
NG092003
|
Assuming no energy transfer between a ball and the track it is moving in, the amount of energy the ball has after it goes over a hill will be the same as before it went over the hill.
| N/A | 16% |
29% | |
NG094003
|
Assuming no energy transfer between a ball and the track it is moving in, the amount of energy the ball has after it goes over a hill will be the same as before it went over the hill because the total amount of energy in the system did not change.
| N/A | 15% |
27% | |
NG067003
|
As a ball rolls back and forth along a curved track and the ball and track get a little warmer, the total energy of the ball and track system does not change because no energy was added or released from the system.
| 15% | 14% |
24% | |
NG086003
|
Assuming no energy transfer between a roller coaster car and the track it is moving in or between the car and the air around it, all of the hills that a roller coaster car can get over must be lower than the height of the starting point.
| N/A | 15% |
17% | |
NG104002
|
Assuming no energy transfer between a ball and the track it is moving in, the speed of the ball will be the same before and after rolling down into and up out of a dip because the total amount of energy in the system does not change.
| N/A | 9% |
16% | |
NG069005
|
In a situation involving two slides, and assuming no energy transfer between the slides and the students sliding on them or between the students and the air around them, two students of the same mass sliding down differently shaped slides will have the same speed at the bottom of the slides because the only source of motion energy is the change in gravitational potential energy, and both students experience the same change in gravitational potential energy.
| N/A | 10% |
14% | |
Frequency of selecting a misconception
Misconception
ID Number |
Student Misconception |
Grades
4–5 |
Grades
6–8 |
Grades
9–12 |
NGM042 |
In a situation involving two frictionless slides of the same height, the speed of an object released from the top will be greater at the bottom for the slide that has a steeper initial slope (Singh & Rosengrant, 2001, 2003). | N/A | 51% |
52% |
NGM009 |
An object has energy within it that is used up as the object moves (Brook & Driver, 1984; Kesidou & Duit, 1993; Loverude, 2004; Stead, 1980). | 16% | 40% |
39% |
NGM010 |
Energy can be created (Kruger, 1990; Lovrude, 2004; Papadouris et al., 2008). | 32% | 36% |
32% |
NGM005 |
Energy can be transformed into a force (AAAS Project 2061, n.d.). | 26% | 35% |
34% |
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.). | 51% | 37% |
28% |
RGM066 |
For a ball on a frictionless convex track, the mass of the ball, not the height at which it starts, determine how high it will roll (AAAS Project 2061, n.d.). | 49% | 33% |
22% |
RGM058 |
Objects that are typically used to warm or cool other objects (e.g. hot water bottles and cold packs) change the temperature of objects without changing temperature themselves. | N/A | 28% |
20% |
NGM039 |
Conservation of energy means that the amount of each form of energy in a system does not change (Singh & Rosengrant, 2001, 2003). | N/A | 23% |
18% |
EGM058 |
The thermal energy of an object is not related to the temperature of the object (AAAS Project2061, 2008). | N/A | 20% |
18% |
NGM040 |
The total amount of energy an object has cannot change (AAAS Project 2061, n.d.). | 24% | 17% |
20% |
NGM041 |
The total amount of energy in a system is always decreasing (AAAS Project 2061, n.d.). | N/A | 19% |
18% |
NGM060 |
Energy can be destroyed (Kruger, 1990; Trumper, 1998). | 15% | 19% |
17% |
NGM037 |
An object always gains energy as it moves. For example, the height that a pendulum reaches after it is released is greater than its starting height because it gains energy as it swings (Loverude, 2004). | 18% | 18% |
14% |
RGM032 |
The amount of energy an object has is not related to its temperature (AAAS Pilot test, 2013). | N/A | 15% |
14% |
NGM059 |
Energy cannot be transferred from one object to another (AAAS Project 2061, n.d.). | 9% | 8% |
11% |
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.
