A Ranking Task (O'Kuma, Maloney, & Hieggelke, 2000) is an exercise that presents students with a set of variations, sometimes three or four but usually six to eight, on a basic physical situation. The variations differ in the values (numeric or symbolic) for the variables involved but also frequently include variables that are not important to the task. Students are to rank the variations on the basis of a specified physical quantity. Students must also explain the reasoning for their ranking schemes and rate their confidence in their rankings. These tasks require students to engage in a comparison reasoning process that they seldom do otherwise.

The Working Backwards Task, which could also be referred to as a "Physics Jeopardy" task (Van Heuvelen & D'Alessandris, 1999), essentially reverses the order of the problem steps. For example, the given information could be an equation with specific values for all, or all but one, of the variables. The students then have to construct a physical situation for which the given equation would apply. Such working backwards tasks require students to take numerical values, including units, and translate them into physical variables. Working backwards problems also require students to reason about these situations in an unusual way, and they often allow for more than one solution.

What, If Anything, Is Wrong Task (Peters, 1982) requires students to analyze a statement or diagrammed situation to determine if it is correct or not. If everything is correct the student is asked to explain what is going on and why it works as described. If something is incorrect the student has to identify the error and explain how to correct it. These are open-ended exercises so they provide insights into students ideas (since students will often have interesting reasons for accepting incorrect situations while rejecting legitimate situations), and often students' responses provide ideas for other items.

Troubleshooting Tasks are variations on the What, If Anything, Is Wrong Tasks. In these items, the students are explicitly told that there is an error in the given situation. Their job is to determine what the error is and explain how to correct it. These tasks can often produce interesting insights into students' thinking because they will, at times, identify some correct aspect of the situation as erroneous. Once again, this helps develop additional items.

Bar Chart Tasks have histograms for one or more quantities. Frequently histograms are given for before and after some physical process with one bar left off. Students are asked to complete the bar chart by supplying the value for the missing quantity. These are a new, or less frequently used, representation. Requiring the students to translate between whatever other representation they are using and this one is usually quite productive in developing a better understanding. These items can be especially useful since most students seem to adapt to bar chart representations relatively easily.

Conflicting Contentions Tasks present students with two or three statements that disagree in some way. The students have to decide which contention they agree with and explain why. These tasks are very useful for contrasting statements of students' alternate conceptions with physically accepted statements. This process is facilitated in these tasks because they can be phrased as "which statement do you agree with and why" rather than asking which statement is correct or true. These tasks compliment the What, If Anything, Is Wrong Tasks.

Linked Multiple Choice Tasks have one set of answer possibilities that applies to questions about a related set of cases. In these tasks, different variations of the situation are described and the students choose from a limited set of possible outcomes. These items allow for the comparison of how students think about various aspects and/or variations of a situation. These tasks have the nice feature that one gets both the students' answer to a particular question and their pattern of responses for the variations presented.

Predict and Explain Tasks describe a physical situation which is set up at a point where some event is about to occur. Students have to predict what will happen in the situation and explain why they think that will occur. These tasks require situations with which the students are familiar or with which they have sufficient background information to enable them to understand the situation, because if students are not familiar with the situation, they usually do not feel comfortable enough to attempt to answer.

These tasks require students to translate from one representation (e.g., an electric field diagram) to another (e.g., an equipotential curves or surfaces diagram). Students often learn how to cope with one representation without really learning the role and value of representations and their relationship to problem solving. Getting them to go back and forth between/among different representations for a concept forces them to develop a more robust understanding of each representation. Among the representations that will be employed at times are mathematical relationships, so this task can serve at times as a bridge between conceptual understanding and traditional problem solving.

These tasks involve an actual demonstration, but with the students doing as much of the description, prediction and explanation as possible. These demonstrations are similar to Interactive Lecture Demonstrations but are narrower in scope and typically use very simple equipment. These demonstrations should be ones where students feel comfortable making predictions about what will happen and which will produce results they do not expect. The task sheets used during these demonstrations will focus the students' attention on important aspects of the situation.

These tasks present the students with an unreduced expression for a calculation for a physical quantity for a physical situation. They have to decide whether the calculation is meaningful (i.e., it gives a value which tells us something legitimate about the physical situation) or is meaningless (i.e., the expression is a totally inappropriate use of a relation). These calculations should not be what we might call trivially meaningless such as substituting a wrong numerical value into the expression. These items are best when the quantity calculated fits with students' alternative conceptions.

These tasks can take a variety of forms, but what they have in common is that the analysis is qualitative. Frequently students are presented with an initial and final situation and asked how some quantity or aspect will change. Qualitative comparisons (e.g., the quantity increases, decreases, or stays the same) are often the appropriate answer. Qualitative reasoning tasks can frequently contain elements found in some of the other task formats (e.g., different qualitative representations and a prediction or explanation).

These tasks involve students performing a demonstration at their desks (either in class or at home) using a predict and explain format but adding the step of doing it. This "doing it" step is then followed by the reformulating step where students reconsider their previous explanations in light of what happened. These DETs are narrow in scope, usually qualitative in nature, and typically use simple equipment. The task sheets used for the DET guide and focus the students' attention on important aspects of the situation.

These tasks do not involve an actual live demonstration but rather a computer simulation of one. They are very similar to the DETs, in that they use prediction and explanation before running the simulation and are followed by a reformulating step. COSTs can be done either in class using a computer projection system, like the Concept Oriented Demonstrations tasks, or at individual computer stations similar to the DETs. These are focused, but require software and computer systems. COSTs should involve situations where it would be difficult or impossible to actually do or see the results. The task sheets used for COSTs will guide and focus the students on important aspects of the domain.

Curt draws TIPERs not only from the Tutorials materials, but from a variety of other resources as well, including:

• Tools for Scientific Thinking (Thornton, 1992)

• Electric and Magnetic Interactions (Chabay & Sherwood, 1995)

• Matter & Interactions (Chabay & Sherwood, 1999)

• Physics: A Contemporary Perspective (Knight, 1997)

• RealTime Physics (Sokoloff, Thornton, & Laws, 1999)

• Workshop Physics (Laws, 1997)

• Peer Instruction (Mazur, 1997)

• Physics by Inquiry (McDermott, Shaffer & Rosenquist, 1996)

• Understanding Basic Mechanics (Rief, 1995)

• ActivPhysics 1 (Van Heuvelen, 1997)

• ActivPhysics 2 (Van Heuvelen & D'Alessandris, 1999)

• Overview/Case Study (Van Heuvelen, 1992).