Why Do ISLE?

The Investigative Science Learning Environment (ISLE) approach to leaning physics

E. Etkina and D.T. Brookes

When students learn physics, they learn that they have to play an epistemic game. Physics students are acutely aware that they have to “play a game” when they are learning physics. The question is: what sort of game do we want them to play? The most essential thing about the ISLE approach is that it presents students with a set of rules for a non-threatening game that helps students build their identities and abilities as practicing scientists.

Why is it so important to create a non-threatening environment to learn physics?

One of the most common instructional approaches to conceptual change in physics is to ask students to predict what they think will happen in a given physical scenario (e.g., “what do you think will happen when I drop these two metal balls, one that is 100g and one that is 500g?”) Many students will say that the heavier ball will fall faster. The instructor then performs the experiment (she drops the two balls and they strike the ground at the same time). Students observe this unexpected result. It is then assumed that students will realize that their physical intuition needs modifying. Students are expected to resolve the contradiction between their expectations and reality, updating the neural paths in their brain to accommodate the new information and the process of learning physics continues.

This model of student cognition has significant problems because it neglects the emotional part of learning. Research shows that students cling tenaciously to their “incorrect” beliefs, using the idea that the heavier ball fell faster even though they are aware of the outcome of the experiment. Recent research has given us some startling insights into why original ideas are hard to change: People ignore or block out data when it threatens their identity or sense of self. In a recent study, people were shown to be more receptive to factual information that contradicted their world view if they first wrote an essay about a self-selected core value and recalled a time when that value made them feel good about themselves, before the contentious information was presented to them. (Nyhan & Nyhan, B., & Reifler, J. (2010). When corrections fail: The persistence of political misperceptions. Political Behavior, 32(2), 303-330). If you doubt that “elicit, confront, resolve” model of learning physics is threatening to students’ sense of self and identity, take a look at the following quotation from a physics student:

If a physics class is making you question your intuition and/or your confidence in your perception of reality, it is almost certainly striking at the core of your sense of self.

Knowledge is more than facts

Knowledge is a combination of two components: The facts, and the system of rules why which those facts are established. These two components are inseparable from each other. In traditional instruction, while instructors may pay attention to how the physics knowledge is established, it does not “rub off” on students. Here are examples of responses from traditionally taught students who “know” Newton’s third law as identified by their ability to answer the four Newton’s third law questions on the force concept inventory correctly. Students were asked how they knew that Newton’s third law was true:

• 001: Because I took physics 140. I don’t know, I just know that…
• 013: I guess it’s just an established law of physics.
• 014: I remember that from high school…
• 017: …that law is probably one of the only things I took out of physics 140…
• 019: I think it’s one of the laws of physics…
• 033: I remember from my physics class…”every action has an equal and opposite reaction.”
• 037: …just from having a physics class before…forces are always equal when they are opposing each other

In contrast, here are the responses of a group of physics students who took their physics in the ISLE format. They were asked “If someone came to you and asked you: ‘How do you know Newton’s third law is true?’ How would you answer them?”

• 001: I would explain with an example of when a person is pushing against a wall.
• 002: Assuming that this person know of Newton’s first and second law. I would use an everyday real life example such as, me pushing a box of books.
• 003: I’d try saying I know it’s true experimentally and show them somehow. I could use two of those spring thingies we had in class that measures force, hook them up, and pull.
• 005: I would ask them to punch a wall…The pain caused by punching a wall is a result of the force the wall exerts on the fist. As you increase the force behind your punch, the force the wall exerts on your fist increases proportionally, and therefore the pain you experience increases as well.
• 007: By giving them an example…
• 009: I know Newton’s third law is true because my classmates and I assembled an experiment in which we allowed wheeled carts to collide.
• 010: I have, along with others, performed many experiments that support the claim and have not found or devised an experiment that disproves it.

ISLE students achieve this level of epistemological sophistication because they are fully engaged in a process of creating their own physics knowledge by implementing the same reasoning processes that practicing physicists use to create their knowledge. In other words, ISLE physics students learn physics by learning and engaging in the actual process of knowledge creation, by thinking like a physicist. But there is more to the ISLE approach than students practicing physics. By doing it, the students are engaged in the struggle and overcoming difficulties while being in control of their learning. It is this combination of struggle and control that produces people with growth mindset, people who persevere and achieve their goals. Read below more about the ISLE approach to see how it develops growth mind set and provides opportunities to develop grit.

The ISLE Game

The ISLE approach is a game that models the process by which physicists create their knowledge. The key to what makes it non-threatening is that it is like a mystery investigation. That is why we always introduce the ISLE approach with the “ten TVs” activity (or 10 tennis rackets activity or 10 cameras activity – see the textbook Chapter 1). Students construct physics concepts and develop science process abilities emulating the processes that physicists use to construct knowledge. The steps of the ISLE process are as follows: 1. We provide students with some interesting physical phenomenon that they probably observed before but never questioned. 2. Students gather data about the phenomenon, identify interesting patterns and come up with multiple causal or mechanistic explanations for why or how the phenomenon is happening. We say “come up with any crazy idea that could explain this” because we DO NOT want students to feel deeply emotionally attached to their ideas. 3. They then test their explanations by conducting one or more testing experiments. The primary goal is to eliminate explanations rather than “prove” them. This is key to the non-threatening nature of the process. In the ISLE approach, “predicting” means saying what would be the outcome of the testing experiment if a particular hypothesis were true. Ideas that are not eliminated are kept and re-tested with further experimentation. 4. Finally students apply the ideas they have established to solve real-world problems.

The cycle repeats twice, first qualitatively, then quantitatively.

The Four Components of the ISLE approach

1. The first component is a cycle of logical reasoning that repeats for every new topic that is learned. The reasoning logic is a marriage of inductive and hypothetico-deductive reasoning:
   
   Inductive: Observational experiments provide students with interesting data (and patterns) that need to be explained. Students generate multiple explanations based on prior knowledge and analogical reasoning.
   
   Hypothetico-deductive: If this explanation is correct, and I do such and such (perform a testing experiment), then so and so should happen because (prediction based on explanation). But it did not happen, therefore my idea is not correct (judgment). Or and it did happen therefore my idea has not been disproved yet (judgment).
   
2. The second component of the ISLE approach is an array of representational tools that students learn to use to travel around the ISLE cycle and solve real-world problems (applications). These include: pictures, graphs, motion diagrams, force diagrams, impulse-momentum bar charts, work-energy bar charts, electric circuit diagrams, ray diagrams, wave front diagrams, etc.
3. The third component of the ISLE approach is the development of a set of scientific abilities or scientific habits of mind that allow students to travel around the ISLE cycle and solve real-world problems (applications) by thinking like a physicist. Here is an example of a scientific ability that students develop in ISLE: Students are able to identify assumptions they are making and how those assumptions affect a result. Notice that this ability applies in multiple contexts. Assumptions are made in designing a testing experiment and may affect the outcome of that experiment or the conclusions that are drawn from that experiment. Assumptions are made when applying physics knowledge to solve a real-world problem (e.g., figure out how far a projectile will travel). The assumptions made will affect the result of the calculation when compared with the actual outcome (i.e., firing the projectile and seeing how far it actually went). The full set of scientific abilities and the multiple contexts in which they occur are codified in the scientific abilities rubrics.
4. The fourth component is the structure of the ISLE-based course that focuses on collaboration (students work in groups), building a learning community (students share their ideas, seek consensus and learn from each other) and built-in opportunities for the students to improve their work (for example students resubmit lab reports, homework assignments, quizzes, etc.) without punishment for the second or third attempt, which means if the third attempt is worth 100% the students receives this 100%.

Shared language

• Observational experiment is an experiment where you investigate a phenomenon by collecting qualitative or quantitative data without specific expectations of the outcome.
• Description is a statement of what was observed in an experiment without explaining it (qualitatively or quantitatively). It answers the question, “What happened?” You can describe with words, pictures, diagrams, etc. 
• Explanation is a statement of a possible reason for why something happened in the experiment. It answers the questions “why” or “how”. An explanation might contain a hypothetical mechanism of how something happened. If you are collecting data, an explanation might be an inference from the data – why the data look they way they do.
• Hypothesis is a synonym for an explanation. There are multiple hypotheses that can explain what happened. A hypothesis should be experimentally testable.
• Prediction is a statement of the outcome of a particular experiment (before you conduct it) based on the hypothesis being tested. Without knowing what the experiment is, one cannot make a prediction. A prediction is not equivalent to a hypothesis but should be based on the hypothesis being tested.
• Testing experiment is an experiment whose outcome you should be able to predict using the hypothesis being tested. The experiment tests the hypothesis, not the prediction. A testing experiment cannot prove the hypothesis to be correct (if its outcome matches the prediction) but might disprove it (if the outcome does not match the prediction). 
• Assumption is a fact assumed to be true; it is often used in conjunction with a hypothesis to make a prediction. 
• Model is a simplified version of an object, a system, an interaction, or a process under study; a scientist creating the model decides what features to neglect. 
• System is the object (or objects) of interest that we choose to analyze. Make a sketch of the process that you are analyzing. Then, make a light, pretend boundary (a closed, dashed loop) around the system object to emphasize your choice. Everything outside the system is called the environment and consists of objects that might interact with and affect the system’s motion. These are external interactions.
• Physical quantity is a feature or characteristic of a physical phenomenon that can be measured in some unit. A measuring instrument is used to make a quantitative comparison of this characteristic with a unit of measure. Examples of physical quantities are your height, your body temperature, the speed of your car, or the temperature of air or water.