AAAS Science Assessment ^beta

Students are expected to know that:

1. The motion energy of an object depends on both the speed and the mass of the object and that motion energy depends only on these two factors. Motion energy does not depend on other factors such as size, shape, material the object is made of, or direction of motion.
2. Any object that is moving has motion energy (kinetic energy) and the motion energy of an object that is not moving is zero.
3. Objects that have the same mass and are traveling at the same speed have the same amount of motion energy.
4. Increasing an object’s speed will increase the motion energy of the object (regardless of how much the speed is increased) and decreasing an object’s speed will decrease the motion energy of the object (assuming the mass of the object does not change).
5. When the motion energy of an object increases, the speed of the object increases and when the motion energy of an object decreases, the speed of the object decreases (assuming the mass of the object does not change).
6. For objects that have the same mass, the object with the greatest speed will have the greatest motion energy and the object with the lowest speed will have the least motion energy.
7. For objects that have the same mass, the object with the greatest motion energy has the greatest speed and the object with the least motion energy has the least speed.
8. For objects traveling at the same speed (greater than zero), the object with the greatest mass will have the greatest motion energy and the object with the least mass will have the least motion energy.
9. For objects traveling at the same speed (greater than zero), the object with the greatest motion energy has the greatest mass and the object with the least motion energy has the least mass.
10. For objects traveling with the same amount of motion energy, the object with the greatest mass will have the lowest speed and the object with the least mass will have the greatest speed.
11. For objects traveling with the same amount of motion energy, the object with the greatest speed will have the least mass and the object with the lowest speed will have the greatest mass.

Boundaries:

1. We feel that “motion energy” is a more descriptive label than “kinetic energy” for this form of energy. Assessment items will use the phrase “motion energy (kinetic energy)” to avoid confusing students who are familiar with the phrase “kinetic energy.”
2. Students are not expected to know or use the formula ½mv². The sub-ideas above describe qualitative relationships.
3. Students are not expected to compare situations where both the mass and speed vary. In assessment items, either the mass or the speed will be held constant while the other varies so that both variables will not be changed at the same time. However, the case where one object is moving and the other is not (regardless of their masses) is valid.
4. Assessment items will use miles per hour as the unit of speed.
5. Note: The students are not expected to know the difference between “weight” and “mass.” All of the context used in the assessment items will be ones where “mass” and “weight” are proportional to each other. When two objects are being compared, they will be in the same location.
6. This idea refers to motion with respect to the surface of the earth. An object is not moving if its position with respect to a point on the surface of the earth is not changing. Students are not expected to know that because every object is moving relative to some other object, no object has a unique claim to be at rest.
7. This idea is limited to translational kinetic energy. Students are not expected to know about other forms of kinetic energy such as vibrational kinetic energy and rotational kinetic energy.
   

Students are expected to know that:

1. The temperature, the mass of the object, and the material of which the object is made all affect the thermal energy of the object.
2. Every object, regardless of whether it is a solid, a liquid, or a gas, has some thermal energy even if the object’s temperature is very low.
3. Objects that are made of the same material, have the same mass and are at the same temperature have the same amount of thermal energy.
4. The higher the temperature of an object, the more thermal energy the object has, and the lower the temperature of an object, the less thermal energy the object has.
5. When the thermal energy of an object increases, the temperature of the object increases and when the thermal energy of the object decreases, the temperature of the object decreases (assuming the mass of the object does not change).
6. For objects that are made of the same material and have the same mass, the object with the highest temperature will have the most thermal energy and the object with the lowest temperature will have the least thermal energy.
7. For objects that are made of the same material and have the same mass, the object with the greatest thermal energy has the highest temperature and the object with the least thermal energy has the lowest temperature.
8. For objects that are made of the same material and at the same temperature, the object with the greatest mass will have the most thermal energy and the object with the least mass will have the least thermal energy.
9. For objects that are made of the same material and at the same temperature, the object with the greatest thermal energy has the greatest mass and the object with the least thermal energy has the least mass.
10. Objects that are made of different materials may have different amounts of thermal energy even if they have the same mass and temperature.
11. For objects that are made of the same material and have the same amount of thermal energy, the object with the greatest mass will have the lowest temperature and the object with the least mass will have the highest temperature.
12. For objects that are made of the same material and have the same amount of thermal energy, the object with the highest temperature will have the least mass and the object with the lowest temperature will have the greatest mass.

Boundaries:

1. Students are not expected to know or use the formulas associated with thermal energy, such as 3/2 kT and m(ΔT)Cp. The sub-ideas above describe qualitative relationships.
2. This idea refers to macroscopic objects not individual atoms and molecules.
3. Students are not expected to know the relationship between heat and temperature, that heat capacity is a measure of how much the temperature of an object will increase with the addition of a given amount of thermal energy, or why an object could feel colder than other objects at the same temperature. The idea that how an object feels does not necessarily reflect the temperature of the object is a prerequisite idea.
4. Students are not expected to compare situations where both the mass and the temperature of the objects vary. In assessment items, either the mass or the temperature of the objects will be held constant while the other varies so that both variables will not be changed at the same time.
5. Additionally, students are not expected to compare the thermal energy of objects that are made of different materials, e.g., we will ask students to compare the thermal energy of one apple to the thermal energy of another apple not apples to oranges.
6. In this idea, the temperature changes will be limited to those that do not involve changes of state.
7. Students are not expected to know that absolute zero is the temperature a substance would have if all atomic and molecular motion were to stop.
8. Assessment items will use Fahrenheit as the units of temperature, for example, 80ºF.
9. Students are not expected to know that temperature is not a characteristic property of substances.
10. Note: The students are not expected to know the difference between “weight” and “mass.” The words “weight” or “weigh” are used as substitutes for “mass” in situations where such substitutions do not make any difference.
11. Note: The term “heat” can be used in everyday conversation as a verb or a noun. When heat is used as a verb, the meaning is basically to raise the temperature of an object as in “I heated the water.” When heat is used as a noun, it usually is intended to mean some “energy.” While people often use the term “heat” as a synonym for thermal energy, that use is not scientifically correct. Technically, “heat” is the energy transferred from one system to another (or between a system and its environment) due to a temperature difference between the systems (or between the system and its environment). Thus the term “heat” should be used in a manner similar to the word “work” in that it should only be used to describe the energy transferred into or out of a system, not the energy in a system. Students are not expected to know the proper use of the term heat. To avoid confusion, the everyday use of the “heat” as a noun should be avoided in middle school instruction and beyond. The use of “heat” as a verb does not cause a problem, however.

Students are expected to know that:

1. The average speed of it atoms or molecules, the number of atoms or molecules, and the types of atoms or molecules of which the object is made all affect the thermal energy of the object.
2. The thermal energy of an object is the sum of the motion energy (kinetic energy) of all of the individual atoms and molecules that make up the object.
3. Since all matter is made up of atoms and molecules that are in constant random motion, all matter has some thermal energy.
4. When the average speed of the atoms and molecules of an object increases, the motion energy of the atoms and molecules increases and, therefore, the thermal energy of the object increases. When the average speed of the atoms and molecules of an object decreases, the motion energy of the atoms and molecules decreases and, therefore, the thermal energy of the object decreases.
5. When the thermal energy of an object increases, the motion energy and average speed of the atoms and molecules of the object increases. When the thermal energy of an object decreases, the motion energy and average speed of the atoms and molecules of the object decreases.
6. For objects that are made of the same number and type of molecules, the object that is made up of the atoms and molecules with the highest average speed will have the most thermal energy and the object that is made up of the atoms and molecules with the lowest average speed will have the least thermal energy.
7. For objects that are made of the same number and type of atoms and molecules, the object with the greatest thermal energy is made up of the atoms and molecules with the highest average speed and the object with the least thermal energy is made up of the atoms and molecules with the lowest average speed.
8. With all else equal, the greater the number of atoms and molecules, the greater the thermal energy and the fewer the number of atoms and molecules, the lower the thermal energy.
9. With all else equal, the greater the thermal energy, the greater the number of atoms and molecules and the lower the thermal energy, the fewer the number of atoms and molecules.

Boundaries:

1. Students are not expected to know or use the formulas associated with thermal energy, such as 3/2 kT and m(ΔT)Cp. They are also not expected to calculate the thermal energy by summing the kinetic energy of the individual molecules. The sub-ideas above describe qualitative relationships.
2. Students are not expected to know which kinds of atoms/molecules have more thermal energy.
3. They are also not expected to know about internal energy and the potential energy that exists between the atoms and molecules of a substance.
4. Students are not expected to know that absolute zero is the temperature a substance would have if all atomic and molecular motion were to stop.
5. Students are not expected to know the term “kinetic energy.” Assessment items will use the phrase “motion energy (kinetic energy)” to avoid confusing students who are familiar with the phrase “kinetic energy.”

Students are expected to know that:

1. The gravitational potential energy of an object depends on both the distance an object is above the center of the earth and the mass of the object and that gravitational potential energy depends only on these two factors. Gravitational potential energy does not depend on other factors such as speed, size, shape, material the object is made of, or the path the object took to get to the distance above the center of the earth.
2. Objects that have the same mass and are equal distances from the center of the earth have the same amount of gravitational potential energy.
3. Increasing the distance an object is from the center of the earth will increase the gravitational potential energy of the object (assuming the mass of the object does not change) and decreasing the distance an object is from the center of the earth will decrease the gravitational potential energy of the object (assuming the mass of the object does not change).
4. If the gravitational potential energy of an object increases, the distance the object is from the center of the earth must have increased (assuming the mass of the object does not change) and if the gravitational potential energy of an object decreases, the distance the object is from the center of the earth must have decreased (assuming the mass of the object does not change).
5. For objects that have the same mass, the object farthest from the center of the earth will have the most gravitational potential energy and the object closest to the center of the earth will have the least gravitational potential energy.
6. For objects that have the same mass, the object with the greatest gravitational potential energy is the farthest from the center of the earth, and the object with the least gravitational potential energy is the closest to the center of the earth.
7. For objects that are equal distances from the center of the earth (greater than zero), the object with the greatest mass will have the most gravitational potential energy and the object with the least mass will have the least gravitational potential energy.
8. For objects that are equal distances from the center of the earth (greater than zero), the object with the greatest gravitational potential energy has the greatest mass and the object with the least gravitational potential energy has the least mass.
9. For objects that have the same amount of gravitational potential energy, the object with the greatest mass is closest to the center of the earth and the object with the least mass is the farthest from the center of the earth.
10. For objects that have the same amount of gravitational potential energy, the object that is the farthest from the center of the earth will have the least mass and the object that is the closest to the center of the earth will have the greatest mass.

Boundaries:

1. Students are not expected to know the meaning of the term “potential.”
2. Students are not expected to know or use formulas associated with gravitational potential energy, such as mass x gravitational constant x height/distance (mgh). The sub-ideas above describe qualitative relationships.
3. As a result, students are not expected to compare situations where both the mass and distance vary. In assessment items, either the mass or the distance will be held constant while the other varies so that both variables will not be changed at the same time.
4. Additionally, the distance used in the assessment items will be the distance above the center of the earth unless a substitute reference plane, such as the floor, is explicitly stated in the assessment item. When this is the case, the reference plane will be the lowest plane in the context so that there will be only positive values for the distance.
5. Note: The students are not expected to know the difference between “weight” and “mass.” All of the context used in the assessment items will be ones where “mass” and “weight” are proportional to each other. The earth will be used as the context for all assessment items.
6. Note: Any plane on which all points are essentially equidistant from the center of the earth, such as the floor of a room, can be used as a substitute for the center of the earth in determining the amount of gravitational potential energy an object has. Because all points on this reference plane are considered to be equidistant from the center of the earth, all objects on the plane can be considered to have zero gravitational potential energy. (There will be only one reference plane that applies to all objects in the situation.) In assessment items the “reference plane” will be referred to as a “reference point.”

Students are expected to know that:

1. An elastic object is an object that changes shape when stretched or compressed and returns to its original shape on when not stretched or compressed.
2. An elastic object that is not stretched or compressed has no elastic energy.
3. Elastic objects that are made of the same material and are stretched (or compressed) the same amount have the same amount of elastic energy.
4. The elastic energy of an elastic object can be increased by stretching or compressing the object out of its original shape. Increasing the amount the object is stretched or the amount of the object is compressed, increases the elastic energy of the object and decreasing the amount the object is stretched or compressed, decreases the elastic energy of an object.
5. For elastic objects that are identical except for how much they are stretched or compressed, the object stretched or compressed the most will have the most elastic energy and the object stretched or compressed the least will have the least elastic energy.
6. For elastic objects that are identical except for how much they are stretched or compressed, the object with the most elastic energy is stretched or compressed the most and the object that has the least elastic energy is stretched or compressed the least.
7. For elastic objects stretched or compressed the same amount (greater than zero), the object that is the most difficult to stretch or compress will have the most elastic energy and the object that is the least difficult to stretch or compress will have the least elastic energy.
8. For elastic objects stretched or compressed the same amount (greater than zero), the object that has the most elastic energy is the most difficult to stretch or compress and the object that has the least elastic energy is the least difficult to stretch or compress.
9. There is a limit to how much an object can be stretched or compressed. If an elastic object is stretched or compressed too much, it may break or not be able to return to its original shape.
10. How much an object is stretched or compressed is measured relative to its unstretched or uncompressed state. They should know that the unstretched or uncompressed length of an elastic object does not determine the amount of elastic energy.
    

Boundaries:

1. Students are not expected to know the meaning of the term “potential.”
2. Students are not expected to know or use formulas associated with elastic energy, such as ½kx². The sub-ideas above describe qualitative relationships.
3. As a result, students are not expected to compare situations where both the amount of stretching or compressing and the properties of the object vary. In assessment items, either the amount of stretching or compressing or the properties of the object will be held constant while the other varies so that both variables will not be changed at the same time.
4. Students are not expected to know which objects are elastic. Assessment items will use only familiar elastic objects such as springs, rubber bands, and rubber balls. Students are not expected to know the stiffness/rigidity of specific materials or the spring constants of specific springs. In assessment items, the relative rigidity will be provided when necessary.
5. When comparing objects in assessment items, we will not have a situation where one object is stretched and another object is compressed. Additionally, we would not compare an object in a stretched and compressed state.
6. In assessment items, objects will not be stretched or compressed beyond the point where they would return to their original shape (i.e. no plastic deformation).
7. When dealing with springs, students are not expected to know the effect of combining springs in series or parallel on the elastic energy of the springs. Students are also not expected to know about how the geometry of the spring relates to the overall elasticity of the spring.
   

Students are expected to know that:

1. Within a system, one form of energy can be transformed into one or more other forms of energy.
2. A decrease in one form of energy within a system is associated with an increase in one or more other forms of energy (unless energy is transferred into or out of the system). Similarly, an increase in one form of energy within a system is associated with a decrease in one or more other forms of energy (unless energy is transferred into or out of the system).
3. Any form of energy can be transformed to other forms of energy and any form of energy can result from a transformation.
4. Energy and force are two different concepts and one cannot be transformed into the other.
5. Energy transformations can occur when energy is transferred from one system to another.
6. Most of what goes on in the universe—from exploding stars and biological growth to the operation of machines and the motion of people—involves some form of energy being transformed into one or more other forms of energy.

Boundaries:

1. Although students are expected to know that when energy is transformed, a decrease of one form of energy is accompanied by an increase in one or more other forms of energy and vice versa, they are not expected to know that the total amount of energy in the system is conserved.
2. Students are not expected to keep track of how much of one form is converted into another.
3. Students are also not expected to know the relationship between energy and work.
4. They will be assessed on energy transformations involving motion energy (kinetic energy), thermal energy, gravitational potential energy, and/or elastic potential energy.
5. Students will not be assessed on energy transformations involving electrical energy, sound energy, chemical potential energy, or radiant energy because we have not yet developed clarifications and items aligned to these ideas.

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.

Students should know that:

1. 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, even though the forms of energy present may change.
2. If the total amount of energy in a system seems to decrease or increase, energy must have gone somewhere or come from somewhere outside the system.
3. 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).
4. Energy can neither be created nor destroyed but it can be transferred and/or transformed.
5. 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:

1. Students are not expected to quantitatively keep track of changes of energy in a system.
2. Assessment items will avoid using the phrase “energy conservation” or “conservation of energy” because of the misconceptions associated with them (see list of misconceptions).
3. Students are not expected to know about energy-mass conversions such as nuclear reactions or other subatomic interactions.