Thought Experiments and Virtual Labs
Thought experiments and virtual labs in one page
- Thought experiment: Imagining a setup that would be impossible, expensive, or dangerous to build, and reasoning out what would happen. Galileo, Einstein, and Newton each made foundational discoveries this way.
- Virtual lab: Software that lets students run real experiments in a simulated environment. Brigham Young University’s virtual chemistry lab is a well-known example, used by about 150,000 students.
- Why both matter for teaching: Many concepts can only be reached through experiments. Most schools cannot afford or risk the physical version. Thought experiments and virtual labs make the experiments possible anyway.
- Open-ended vs closed-ended: Closed experiments have a fixed procedure and an expected outcome. Open experiments give students a question and let them choose how to investigate. Open experiments build the deeper learning; closed experiments build the basic procedure.
Some of the most important ideas in science were discovered without any equipment. Galileo argued that heavy and light objects fall at the same rate by imagining them tied together. Einstein worked out parts of relativity by imagining what would happen if he chased a beam of light. Newton imagined a cannon fired horizontally with enough force to fall around the Earth instead of into it.
None of these experiments could have been built at the time. The point was not to build them; the point was that reasoning through what would happen produced understanding the real experiment could not. Thought experiments are a tool teachers have always had, but rarely use systematically.
The technological version of the same idea is the virtual lab. A simulated environment where students can run experiments that would be too expensive, too dangerous, or too long to run physically. Together, thought experiments and virtual labs open up a kind of teaching that the physical-lab-only model could not.
Thought experiments as a teaching method
A thought experiment in the classroom follows a specific shape.
The teacher poses a setup the students can imagine but probably have not seen. A specific object, a specific force, a specific scenario. The setup has to be vivid enough to picture.
Students predict what would happen. This is the work. They use whatever they already know to reason out the result. Different students often predict different things, which is good; the disagreement is what drives the next step.
The teacher reveals the actual answer. Sometimes this is a fact (the answer turns out to be X), sometimes a follow-up question that exposes a contradiction in the most common prediction. The student who predicted wrong now has new information that does not fit their old model.
Students update their thinking. The contradiction creates cognitive disequilibrium; the resolution is the learning.
A classic example: ask students whether a feather and a hammer dropped on the moon would land at the same time or different times. Most students predict the hammer lands first, because that is their experience on Earth. The teacher then shows the Apollo 15 video of Commander David Scott actually performing this experiment on the moon in 1971. Both land together. The students now have to reconstruct their model of gravity to account for the fact that air resistance was the only thing producing the difference on Earth.
The lesson took three minutes. No equipment was needed beyond a short video. The same concept lectured for thirty minutes would not lodge as deeply.
Imagining a setup that would be impossible, expensive, or dangerous to build, and reasoning out what would happen.
Useful in teaching because many important concepts require experiments students cannot run physically. A well-posed thought experiment surfaces students’ current beliefs, sets up a prediction, and creates the cognitive disequilibrium that drives deep learning.
Open-ended vs closed-ended experiments
A physical lab usually runs closed-ended experiments. The procedure is fixed: mix this with that, heat for three minutes, record the colour change. The expected outcome is known. If a student gets a different result, the assumption is that they made a mistake in the procedure.
Closed experiments are not useless. They teach the procedure and let students see a known effect with their own hands. The student finishes the lab knowing how oxygen gas can be produced and tested, or how an acid-base reaction proceeds.
The deeper learning comes from open-ended experiments. A student is given a question, not a procedure. Investigate why the seasons change. Find out which materials conduct electricity. Discover how the angle of a ramp affects the speed of a ball at the bottom. The student designs the experiment themselves, runs it, interprets the result, and defends what they found.
Open experiments build different skills: hypothesis generation, experimental design, dealing with messy data, defending an interpretation against others. These are the skills science actually requires; closed experiments do not build them.
The problem with open experiments in physical labs is risk and cost. A student designing their own chemistry experiment could mix something dangerous. A student designing their own electrical experiment could damage equipment or themselves. Schools default to closed experiments because the risk is bounded.
Virtual labs change this calculation.
Virtual labs and open-ended experimentation
A virtual lab is a simulation of a physical lab, accurate enough to let students do real experimental reasoning, with none of the physical risk.
Brigham Young University’s virtual chemistry lab is one of the best-known examples. It serves about 150,000 students. Students can mix any combination of available reagents, in any quantity, at any temperature. The simulation tells them what would happen. A combination that would be dangerous in the real lab causes a simulated explosion; the student notes the result and moves on.
A virtual lab makes three things possible that a physical lab cannot.
Open-ended exploration is safe. A student who mixes the wrong things in a virtual lab causes a virtual explosion. No one is hurt, no equipment is destroyed, and the student learns from the mistake.
Many experiments per period. A real chemistry experiment takes setup time, run time, and cleanup time. A virtual one takes seconds. A student can run twenty experiments in the time a real lab gets through one or two.
Access for schools without lab equipment. A school without a chemistry lab can still teach experimental chemistry through a virtual one. The cost of the software is shared across many schools.
The virtual lab does not replace the physical one entirely. Students still benefit from doing some real experiments to see physical materials behave physically. But it opens up a much wider range of experimentation than the physical lab alone allows.
Designing a lesson that uses these methods
A thought-experiment or virtual-lab lesson follows a similar structure to other inquiry lessons.
Start with a question, not an answer. The teacher’s job is to pose a question that students can investigate. The question should be specific enough to investigate (“which of these materials conducts heat fastest”) but open enough that students can design the investigation themselves.
Let students predict before they experiment. Ask each student to write down what they think will happen and why. This commits them to a position and surfaces the prior beliefs that the experiment will either confirm or break.
Let them run the experiment. Whether the experiment is in the head (a thought experiment) or on a screen (a virtual lab) or on a real bench (a physical lab), the student should do the running. The teacher does not run it for them.
Compare result to prediction. This is the learning moment. The students who predicted right confirm and deepen their model. The students who predicted wrong have a specific gap to address. Both groups update.
Discuss in a group. Different students often see different things in the same experiment. Comparing notes surfaces assumptions and disagreements that the teacher can then address.
The teacher’s role across all of this is to ask questions, not to give answers. The lesson works because students do the reasoning; if the teacher tells them what they should have predicted, the cognitive work stops.
Common misreadings
Thought experiments are not just hypotheticals. The difference between a useful thought experiment and a hypothetical question is that the thought experiment has a definite right answer that can be reached by reasoning. “What if the moon was made of cheese” is a hypothetical. “What would happen if you dropped a feather and a hammer in a vacuum” is a thought experiment, because physics gives a specific answer.
Virtual labs are not just animations. A video showing a chemistry reaction is not a lab; the student cannot try a different combination. A virtual lab is interactive: the student chooses the inputs and sees the corresponding outputs.
And neither replaces real experimentation entirely. Students still benefit from doing some experiments physically. The argument is that virtual labs and thought experiments expand the range of experiments accessible to a typical classroom, not that they replace the physical lab.
Interactivity. A virtual lab lets the student choose inputs and see the corresponding results; a video shows one fixed run of one experiment.
A virtual lab supports student-driven open-ended experimentation. A video shows a finished demonstration. Both have uses, but only the lab supports the kind of reasoning that builds experimental skills.
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