Force Concept Inventory Answer Key
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- The bad news is, there are no quick fixes! The central concept of Newtonian mechanics is force, so we have designed an instrument to probe student beliefs on this matter and how these beliefs compare with the many dimensions of the Newtonian...
- In the body of the article we discuss the design of the instrument, how to use it, and results obtained with it so far. The instrument has proven valuable at every level of introductory physics instruction from high school to Harvard University. We...
- All six are required for the complete concept. The kinematics dimension, for example, is essential because the Second Law presupposes the acceleration concept. Physics teachers need no explanation for the rest of the table. Note, though, that each dimension is probed by questions of more than one type. The first impression of most physics professors is that the Inventory questions are too trivial to be informative. This turns to shock when they discover how poorly their own students perform on it. It is true that the Inventory questions avoid the real complexities of mechanics. But such "trivial questions" are more revealing when they are missed. The Inventory questions are only probes for Newtonian concepts, so one should not give great weight to individual items.
- There are occasional false positives in the responses of non-Newtonians and false negatives from Newtonians. But only a true Newtonian generates a consistent pattern of Newtonian choices with an occasional lapse at most. Thus, the Inventory as a whole is a very good detector of Newtonian thinking. As a rule, "errors" on the Inventory are more informative than "correct" choices. The commonsense alternatives to the Newtonian concepts are commonly labeled as misconceptions. They should nevertheless be accorded the same respect we give to scientific concepts. The most significant commonsense beliefs have been firmly held by some of the greatest intellectuals in the past, 2 including Galileo and even Newton.
- They happen to be false, but that is not always so easy to prove, especially if they are dismissed without a hearing as ill conventional instruction. The Inventory, therefore, is not a test of intelligence; it is a probe of belief systems. Table II contains a taxonomy of commonsense misconceptions probed by the Inventory. A more detailed taxonomy has been described elsewhere, 2 so we can be brief without attempting completeness. The table lists 28 distinct misconceptions along with corresponding Inventory items that suggest their presence when selected. They have been grouped into six major commonsense categories, which correspond as closely as possible to the six major Newtonian concepts or concept dimensions in Table I.
- Each commonsense category contains a set of misconceptions about the corresponding Newtonian concept. It will be instructive to discuss each category in turn. KinematicsIn kinematics it is not really appropriate to speak of commonsense misconceptions. Rather, the typical commonsense concept of motion is vague and undifferentiated. Accordingly, as indicated in the Kinematics category in Tables I and II, the Inventory probes for the ability to distinguish between position, velocity, and acceleration, as well as to recognize the vectorial nature of velocity and acceleration. The most rudimentary concept of acceleration is "to know one when you see one. This is reflected in the use of language. Thus terms like "force," "energy," and "power" are often used interchangeably, as are the terms "velocity" and "acceleration.
Evaluating The Force Concept Inventory For Different Student Groups At NTNU
The term "impetus" dates back to pre-Galilean times before the concept was discredited scientifically. Of course, students never use the word "impetus"; they might use any of a number of terms, but "force" is perhaps the most common. Impetus is conceived to be an inanimate "motive power" or "intrinsic force" that keeps things moving. Evidence that a student believes in some kind of impetus is therefore evidence that the First Law is not understood. For an object to move it must be supplied with impetus, as expressed by commonsense concept I1 in Table II. As expressed by concepts I2, I3, and I4, impetus can be gained or lost in a variety of ways that vary from student to student. Note the underlying "container metaphor" in the impetus concept: Every object is like a container that can store a supply of impetus, like a car stores gas, a kind of "go power" to keep it moving. A few students believe in circular impetus commonsense concept I5 that tends to move objects in circles; they have been known to justify this by a "training metaphor," which holds that objects tend to do what they have been "trained" to do in the past.- Active agents are causal agents-they have the power to cause motion-to create impetus and transfer it to other objects, as when a boy throws a ball. As indicated by category 2 in Tables I and II, active force is the commonsense concept that corresponds most closely to Newton's Second Law. The commonsense notion closest to a "causal law" is expressed by the syllogism:Every effect has a cause. Motion is an effect. Therefore, motion has a cause. This leads to the commonsense concept AF2 motion implies active force. The vague commonsense analog of the Second Law is that active forces produce motion.
- When velocity and acceleration are not discriminated as descriptors of motion, it is to be expected that the concept "velocity is proportional to force" commonsense concept AF4 is not distinguished from "acceleration is proportional to force. Note the metaphor of an "acting person" for an active force. As a technical point, it will be noted that the commonsense belief AF1 only active agents produce forces is not evident in the choices A and Bin question I5. However, we listed it as so in Table II, because to justify those choices in interviews, students appealed to AF1. Here "more forceful" can mean "bigger," "greater mass," or "more active," as in commonsense concepts ARI greater mass implies greater force , and AR2 most active agent produces greatest force. Because of its strong metaphorical base, the dominance principle though it is seldom clearly articulated is so natural to students that it is one of the last misconceptions to be, overcome in the transition to Newtonian thinking.
- Indeed, it is still to be found in some physics graduate students, as noted in Section III. Concatenation of InfluencesCommon sense offers a number of alternatives, as shown I in category 4 of Table II, to the Newtonian force superposition principle. Students often apply the dominance principle to the composition of two forces acting on the same object, with one force winning out over the other.
The Problem Of Revealing How Students Think: Concept Inventories And Beyond
This is another example of poorly differentiated concepts so typical of commonsense thinking. Other Influences on MotionUnlike the Newtonian world, the world of common sense does not have a unitary concept of force. Besides active forces, there are other influences on motion, as listed in category 5 of Table II. Actually, the Inventory does not contain any items designed specifically to probe for the centrifugal force misconception listed in the table. That misconception is only suggested by the form that the listed items take in the questions. Verification would require an interview or explanation from the students. We have encountered high-school physics teachers who think that centrifugal force is a distinct kind of force. Such is the power of a name! In the world of common sense, obstacles like chairs and walls do not exert forces, "they just get in the way. Motion occurs only when the active force "overcomes" the resistance note the metaphor , and it ceases when the force becomes "too weak.- Concept G3 may appear to be true, but the underlying misconception is a matter of scale, to which common sense is often oblivious. It is believed that gravity varies significantly over a few meters, whereas the variation is actually about one part in 10 The belief G1 that air pressure contributes to gravity is common only among very naive students.
- Among other things, question 12 was designed to detect this misconception. The fact that the net force due to air pressure is actually upward buoyant force instead of downward, was hardly recognized by students at any level, for item 12D was very rarely selected. Interviews of 16 graduate students revealed that only two of them really understood the buoyant force concept.
- A third of the others could state Archimedes principle, but they did not know that the buoyant force is due to a pressure gradient, and some offered very peculiar hypotheses to explain it. No doubt this sorry state of affairs is largely due to the fact that buoyancy gets little attention in the physics curriculum today. Because of all this, item 12D is not very informative, and we allow 12B as an acceptable Newtonian choice. We have retained item 12D, nevertheless, because it is such a good pretext to interview students about buoyant force.
- Besides, some teachers might think physics students should know why things float! Results and ImplicationsThe Force Concept Inventory test has been given to more than high-school students and more than university students. Results are displayed in Table III along with post test scores on the Mechanics Baseline, described in a companion paper. Except for two of the authors Wells and Swackhamer , all teachers with class test results in Table III were blind to both tests when their teaching was done.
- These results have been replicated in a number of studies involving students at a range of institutions see sources section below. That said, there remains questions as what exactly the FCI measures. Since the development of the FCI, other physics instruments have been developed. In addition to physics, concept inventories have been developed in statistics , [12] chemistry , [13] [14] astronomy , [15] basic biology , [16] [17] [18] [19] natural selection , [20] [21] [22] genetics , [23] engineering , [24] geoscience. An example of an inventory that assesses knowledge of such concepts is an instrument developed by Odom and Barrow to evaluate understanding of diffusion and osmosis. Caveats associated with concept inventory use[ edit ] Some concept inventories are problematic. The concepts tested may not be fundamental or important in a particular discipline, the concepts involved may not be explicitly taught in a class or curriculum, or answering a question correctly may require only a superficial understanding of a topic.
(PDF) Force Concept Inventory | David Hestenes - Medicoguia.com
It is therefore possible to either over-estimate or under-estimate student content mastery. While concept inventories designed to identify trends in student thinking may not be useful in monitoring learning gains as a result of pedagogical interventions, disciplinary mastery may not be the variable measured by a particular instrument. Users should be careful to ensure that concept inventories are actually testing conceptual understanding, rather than test-taking ability, language skills, or other abilities that can influence test performance.- The use of multiple-choice exams as concept inventories is not without controversy. The very structure of multiple-choice type concept inventories raises questions involving the extent to which complex, and often nuanced situations and ideas must be simplified or clarified to produce unambiguous responses. For example, a multiple-choice exam designed to assess knowledge of key concepts in natural selection [20] does not meet a number of standards of quality control.
The Force Concept Inventory And Adult Learners - Physics LibreTexts
Login or register to download the answer key and an excel scoring and analysis tool for this assessment. Typical Results Typical results from Von Korff et al. Courses taught using interactive engagement methods have higher normalized gains than those taught using traditional lecture. These results are from a metaanalysis of FCI gains for 31, students in classes, published in 63 papers. The FCI has also been given to tens of thousands of students in high school and outside of the US, who are not included in this study.- The average normalized gain is 0. Get 1-click statistics Compare to students like yours Get practical, personalized recommendations Learn more! The latest version of the FCI, released in , is called v The original version has 29 questions Hestenes et al. There are also several variations of the FCI. It was written at a 7th grade reading level and includes more illustrations, but tests for the same concepts. Osborn Popp and Jackson Another variation is less similar to FCI: The Representational Variant of the FCI takes nine questions from the original FCI and redesigns them using various representations such as motion map, vectorial and graphical , yielding 27 multiple-choice questions concerning Newton's first, second, and third laws, and gravitation.
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