ISLE - Investigative Science Learning Environment

E. Etkina, D. Brookes, A. Van Heuvelen

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 ISLE 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 & Reifler, submitted) 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:

“I have the attitude that I should just believe what they [physics teachers] tell me…the things I see in physics are completely different than what I would normally expect them to be…Even though I’ve seen it in lab, I say “OK, I’m just going to pretend it’s true,” and I work the problems like that…I don’t believe what I’m seeing. I think if I took more classes, and I saw it more often, I wouldn’t have to play that game, where I pretend that’s right. But that’s what I do right now…It [the game] seems like there are these strange and crazy things going on out there, things that don’t make any sense.” (ref. 3, p.216)

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.

The ISLE Game

ISLE 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 ISLE with the “ten TVs” activity. Students construct physics concepts and develop science process abilities emulating the processes that physicists use to construct knowledge. The steps of the ISLE cycle proceed as follows: 1. Students come upon some interesting physical phenomenon that needs explaining. 2. Students gather data about the phenomenon, identify interesting patterns and come up with multiple mechanistic explanations for why 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 ISLE, “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. Finally students apply the ideas they have established to solve real-world problems.

The cycle repeats twice, first qualitatively, then quantitatively.

ISLE Cycle
The Three Components ISLE
  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 (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 ISLE 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 ISLE 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.
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.
    Physical quantities that contain information about the direction of some quantity are called vector quantities and are written using symbols with an arrow on top . Force and velocity are vector quantities. Physical quantities that do not contain information about direction are called scalar quantities and are written using italic symbols (m, T, and q). Mass is a scalar quantity, as is temperature.
  • Operational definition is a rule that tells you what to do (what other quantities to measure and what mathematical operations to use) if you need to determine the value of a particular quantity. For example, for motion at constant velocity,
    is an operational definition of velocity.
  • Cause-effect relationship is a rule that tells you what will happen to a quantity when another quantity changes. For example, for motion at constant velocity, x=vdelta_t is a cause-effect relationship that shows if the time interval of travel is doubled, the distance traveled is doubled. However, the operational definition of velocity is not a cause-effect relationship because if you double the distance that the object travels, the velocity will not change (since the time interval for the doubled distance will be doubled too).


Below is a survey of 21st century learning goals for high school and STEM graduates. How can we design our physics courses so that they are more aligned with these goals?

Studies about the Desired Outcomes of 21st Century Science, Engineering and Technology Education

What knowledge and what abilities are needed to succeed in this 21st century workplace? This question has been addressed by individual research studies examining the need for various process abilities and for declarative knowledge of people in that workplace. , , , Duggan and Gott studied the science used by employees in five science-based industries: a chemical plant specializing in cosmetics and pharmaceuticals, a biotechnology firm specializing in medical diagnostic kits, an environmental analysis lab, an engineering company manufacturing pumps for the petrochemical industry, and an arable farm. They found that most of the scientific conceptual understanding used by employees was learned on the job, and not in high school or university courses. They concluded: “A secure knowledge of procedural understanding appeared to be critical.”9 Aikenhead summarized his own and other studies as follows: “In science-rich workplaces, procedural knowledge had a greater credence than declarative knowledge (Chin et al.4), and employees consistently used concepts of evidence in their work to such an extent that Duggan and Gott9 concluded: “procedural knowledge generally, and concepts of evidence specifically, lie at the heart of … science-based occupations.” In addition to individual research studies like these, there have been a plethora of national studies and reports concerning desired outcomes of science education.

The National Science Foundation Shaping the Future 1996 review of science, mathematics, engineering, and technology (SME&T) education

“It is important to assist students to learn not only science facts but, just as important, the methods and processes of research, what scientists and engineers do, how to make informed judgments about technical matters, and how to communicate the work in teams to solve complex problems.”

“…all students learn these subjects by direct experience with the methods and processes of inquiry.”

“…there is no disagreement that every student should be presented an opportunity to understand what science is, and is not, and to be involved in some way in scientific inquiry, not just “hands-on” experience.”

“Research … suggests that working in groups in a cooperative setting produces greater growth in achievement than straining for relative gains in a competitive environment.”

“Also very important is the observation made by many, particularly employers, that a well-designed, active learning environment assists in the development of other skills and traits they seek in employees: cognitive skills (problem solving, decision-making, learning how to learn), social skills (communications and teamwork), and positive personal traits (adaptability and flexibility, openness to new ideas, empathy for ideas of others, innovative and entrepreneurial outlook, and a strong work ethic). This point has been made repeatedly in testimony at our hearings and in published studies and reports.”

Section VII of the report contained a list of suggestions for SME&T faculty concerning teaching and learning. We provide below four of the ten items in that list.

  • C. Build into every course inquiry, the processes of science (or mathematics or engineering), a knowledge of what SME&T practitioners do, …
  • D. Devise and use pedagogy that develops skills for communication, teamwork, critical thinking, and lifelong learning in each student.
  • E. Make methods of assessing student performance consistent with the goals and content of the course.
  • F. Start with the student’s experience; understand that the student may come with significantly incorrect notions; and relate the subject matter to things the student already knows.

Next Generation Science Standards

The next generation science standards for K-12 science classrooms identify three dimensions of science proficiency: Scientific practices, cross-cutting concepts, and disciplinary core ideas. The accompanying NRC report introduces the dimension of scientific practices with the following sentence. “From its inception, one of the principal goals of science education has been to cultivate students’ scientific habits of mind, develop their capability to engage in scientific inquiry, and teach them how to reason in a scientific context .” The report identifies 8 key scientific practices:

Practices for K-12 Science Classrooms

  • Asking questions
    • By grade 12 students should be able to ask “what,” “how,” and “why” questions, distinguish between a scientific and non-scientific question, use questions to design investigations, and ask questions as a part of scientific argument (how do you know? what evidence supports this argument?).
  • Developing and using models
    • By grade 12 students should be able to construct various representations, represent and explain phenomena with multiple models, discuss limitations of a model, and refine a model in the light of evidence.
  • Planning and carrying out investigations
    • By grade 12 students should be able to formulate a question, decide what data to collect and how measurements will be recorded, identify dependent and independent variables, and consider possible confounding variables.
  • Analyzing and interpreting data
    • By grade 12 students should be able to identify patterns in data, recognize when data is consistent with or in conflict with expectations, summarize and display data to explore relationships using tables, graphs, statistics, mathematics etc., evaluate the strength of a conclusion drawn from data, and distinguish between causal and correlational relationships.
  • Using mathematics and computational thinking
    • By grade 12 students should be able to conduct dimensional analysis, express quantities and relationships with mathematics, and use appropriate level of mathematics & statistics to analyze data.
  • Constructing explanations
    • By grade 12 students should be able to construct their own explanations, use models and evidence to support or refute an explanation, offer causal explanations, identify gaps or weaknesses in explanations, and solve problems by appropriately applying scientific knowledge.
  • Engaging in argument from evidence
    • By grade 12 students should be able to support a claim with data, identify weaknesses in their own or others’ arguments, recognize the major features of scientific argument, explain how knowledge claims are evaluated in the scientific community, critically read media reports related to science and technology.
  • Obtaining, evaluating and communicating information
    • By grade 12 students should be able to use multiple representations to communicate understanding, read and understand an appropriate scientific text, and discuss the validity and reliability of the data, hypotheses, and conclusions of primary scientific literature or a media report.

Rather than suggest which practices should be mastered at particular grades the next generation science standards suggest that each of these practices should be integrated into inquiry activities from the earliest grades through to grade 12. Students gain a deeper understanding of these practices and are able to conduct more sophisticated investigations using these practices as they progress through the grades.