Science Assessment ~ Ideas ~ 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.

Key Idea: Models are useful for thinking about real-world objects, events, and processes.

Sub-Ideas
Items & Student Performance
Misconceptions
NGSS

Students are expected to know that:

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).
Examples:
- 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
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.
Use of models makes it possible to illustrate abstract aspects of a phenomenon (e.g. arrows to represent forces).
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.
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	Grades 6–8	Grades 9–12
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%
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%
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%
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%
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%

Frequency of selecting a misconception
Misconception ID Number	Student Misconception	Grades 6–8	Grades 9–12
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%

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.

No NGSS statements are associated with this idea in the selected project.