Topics-+Models

Topic: Models
Below is a list of key ideas related to Models. For each key idea, you will find a list of sub-ideas, a list of items, results from our field testing, and a list of student misconceptions. After clicking on a tab, click on it again to close the tab.

Geometric figures, number sequences, graphs, diagrams, sketches, number lines, maps, and oral and written descriptions can be used to represent objects, events, and processes in the real world.
//Students are expected to know that////:// //Boundaries//:
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) The term //model// refers to a representation of something in the real world.
 * 2) Models can represent objects.
 * 3) Models can represent events or processes.
 * 4) Geometric figures, diagrams, sketches, and maps can be used as models.
 * 5) Number sequences and graphs can be used as models.
 * 6) Oral and written descriptions can be used as models.
 * 1) Students are not expected to know that simulations are examples of models.
 * 2) Students are not expected to know that mathematical statements or symbolic equations are examples of models.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|MO007001] || [|Both a map and a globe are representations of Earth (uses pictures).] || 59% || 64% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/2788"]] ||
 * [|MO079001] || [|An object, event, or process can be represented with a model.] || 64% || 57% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3585"]] ||
 * [|MO072001] || [|Both a graph and a diagram can be used as a model.] || 60% || 61% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3578"]] ||
 * [|MO017003] || [|Both a heart and the flow of blood can be modeled.] || 56% || 66% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3538"]] ||
 * [|MO004001] || [|Both a map and a globe are models of Earth.] || 62% || 53% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/2785"]] ||
 * [|MO013001] || [|Both objects and processes can be modeled.] || 54% || 61% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/2878"]] ||
 * [|MO012001] || [|Both objects and events can be modeled.] || 57% || 54% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/2877"]] ||
 * [|MO003003] || [|Both a drawing of a heart and a piece of clay shaped like a heart can be used as models of a heart.] || 56% || 52% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3531"]] ||
 * [|MO019002] || [|Both a car and a car crash can be modeled because both objects and events can be modeled.] || 54% || 53% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3539"]] ||
 * [|MO016003] || [|Both a car and the wearing out of tires can be modeled.] || 52% || 50% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3537"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || 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.
 * ~ Student Misconception ||~ Grades
 * [|MOM002] || [|A model is always a three-dimensional object. Therefore, pictures, diagrams, graphs, written descriptions, abstract mathematical or conceptual models are not models (Grosslight, et al., 1991).] || 36% || 43% ||
 * [|MOM005] || [|Only physical objects can be modeled; events and processes cannot be modeled (Grosslight et al., 1991).] || 37% || 36% ||

A model of something is similar to but not exactly like the thing being modeled.
//Students are expected to know that://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) A model represents (brings to mind) one or more aspects of the thing being modeled.
 * 2) While a model represents one or more aspects of the thing being modeled, it does not represent all aspects of the thing being modeled.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|MO024003] || [|A model can be bigger or smaller than the thing it represents.] || 61% || 77% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3542"]] ||
 * [|MO022004] || [|A model is similar to the thing it represents in some ways but different in other ways.] || 58% || 69% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3540"]] ||
 * [|MO081001] || [|A model can be a different shape than the thing it represents, and it can be made from different materials.] || 35% || 38% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3587"]] ||
 * [|MO080001] || [|A model can be different from the thing it represents in both size and shape.] || 31% || 29% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3586"]] ||
 * [|MO082001] || [|A model can be a different shape than the thing it represents, and it can be a different color.] || 25% || 27% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3588"]] ||
 * [|MO025003] || [|A model sometimes looks quite different from the object it is supposed to represent.] || 17% || 14% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3543"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || 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.
 * ~ Student Misconception ||~ Grades
 * [|MOM003] || [|A model should look like the object, event, or process it is modeling (with the possible exception that it can be smaller). Therefore, a diagram or graph could be considered a model only if it bore a physical resemblance to what is being represented (Grosslight et al., 1991; Penner et al., 1997; Treagust, et al. 2002; Schwartz & White, 2005).] || 41% || 30% ||

Models are useful for thinking about real-world objects, events, and processes.
//Students are expected to know that:// > Examples:
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) Someone may use a model to think about (i.e. to visualize or imagine and to reason with or reflect upon) objects, events, and processes in the real world (phenomena).
 * Objects: Earth (how much is covered by land vs. water), Moon (how cratered it is), Sun, Earth-Moon-Sun System (relative sizes, relative distances, etc.)
 * Events: Eclipse, Earthquake, tsunami, car crash, election, battle
 * Processes: erosion, presidential campaign, chemical reaction, car assembly, plant growth
 * 1) Use of models makes it possible to observe phenomena that would be difficult or impossible to observe in the real world. For example, a phenomenon could happen very slowly, very quickly, on a very small scale, or on a very large scale. The phenomenon could also be too complex, too expensive, or too dangerous to observe directly.
 * 2) Use of models makes it possible to illustrate abstract aspects of a phenomenon (e.g. arrows to represent forces).
 * 3) Use of models makes it possible to ignore some features of a phenomenon being considered so that there is less to keep track of. This allows the exclusion of features that are believed to be irrelevant in how the phenomena behave (e.g. food web diagrams do not show how predators catch and consume their prey, point masses in a physics problem do not show the actual size and/or shapes of the objects they represent). Whether or not a given feature turns out to be irrelevant depends upon the purpose of the model and how well understood the phenomenon is.
 * 4) A model may be modified as it is being used based on new information about the phenomenon it represents or based on new thinking about what features of the phenomenon are important to represent in the model.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|MO028002] || [|A chemist could use a model to show other people what DNA looks like or to help him/herself think about DNA.] || 75% || 79% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3546"]] ||
 * [|MO030002] || [|A police investigator could use a model of a car crash to figure out how the crash took place or to show others how it took place.] || 72% || 80% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3000"]] ||
 * [|MO026003] || [|An engineer could use a model of a machine to show someone else what the machine is like, or to help him/herself think about how the machine works.] || 68% || 75% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3544"]] ||
 * [|MO031002] || [|A student could use a diagram to help himself figure out the way light travels or to show someone else the way light travels.] || 68% || 76% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3548"]] ||
 * [|MO038004] || [|It is acceptable and sometimes beneficial for a model to lack features of the real thing that are not relevant to what is being studied.] || 37% || 44% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3556"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || 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.
 * ~ Student Misconception ||~ Grades
 * [|MOM003] || [|A model should look like the object, event, or process it is modeling (with the possible exception that it can be smaller). Therefore, a diagram or graph could be considered a model only if it bore a physical resemblance to what is being represented (Grosslight et al., 1991; Penner et al., 1997; Treagust, et al. 2002; Schwartz & White, 2005).] || 48% || 41% ||
 * [|MOM007] || [|A model can only represent aspects of a phenomenon that are already known; it cannot be used to figure out new things (for example, make an accurate prediction) about what is being represented. This still allows one person to use a model to communicate things he or she already knows about something to other people, even if they do not already know it (Grosslight et al., 1991; Schwartz & White, 2005).] || 17% || 14% ||

The usefulness of a model in thinking about objects, events, and processes depends on how closely its behavior matches key aspects of what is being modeled.
//Students are expected to know that://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) Judgments about the usefulness of a model are/should be based on how closely its behavior matches key aspects of what is being modeled (rather than on how attractive it is).
 * 2) The key aspects of the referent that need to be represented accurately in the model depend upon the purposes of the model.
 * 3) The only way to judge the usefulness of a model is to compare its behavior to the behavior of the real-world object, event, or process being modeled.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|MO066004] || [|In order to accurately represent what would happen to a real human in a car crash, crash test dummies should be about as strong and sturdy as a real human body is.] || 69% || 78% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3572"]] ||
 * [|MO061003] || [|If a student is studying how long it would take a spaceship to go between different planets in the solar system, his model should accurately represent the relative distances between the planets, but does not need to accurately represent other aspects of the solar system.] || 62% || 80% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3568"]] ||
 * [|MO065004] || [|An architect does not need to create a 3D model of his house design if his 2D plans show everything that is needed in order to build the house.] || 48% || 49% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3571"]] ||
 * [|MO060002] || [|Whether a globe or a wold map is a better model of the earth depends on the task they will be used for.] || 38% || 41% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3567"]] ||
 * [|MO062002] || [|If a student makes a model of the solar system to think about how long it would take a spaceship to travel between the planets, it is essential for him to accurately represent the relative sizes of and distances between the planets, but it is not essential that he makes the model of each planet look like the planet it represents.] || 33% || 45% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3569"]] ||
 * [|MO063004] || [|If a student wants to make a model of the solar system to think about how long it would take a spaceship to travel between the planets, it is essential to accurately represent the relative sizes and distances, but it is not essential to make each model planet look like the planet it represents.] || 36% || 40% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3570"]] ||
 * [|MO093001] ||  || 28% || 37% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/3599"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || 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.
 * ~ Student Misconception ||~ Grades
 * [|MOM006] || [|The more a model is similar to what is being modeled (particularly with respect to physical similarities), the better the model is (AAAS Project 2061, n.d.).] || 50% || 41% ||
 * [|MOM002] || [|A model is always a three-dimensional object. Therefore, pictures, diagrams, graphs, written descriptions, abstract mathematical or conceptual models are not models (Grosslight, et al., 1991).] || 16% || 15% ||

There is no guarantee that ideas based solely on a model are correct.

 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]