How the University of Colorado Boulder created one of the internet’s most valuable free educational resources — and why every student and teacher should be using it.
A revolution is quietly underway in science classrooms around the world, and it has been for more than two decades. It doesn’t require a textbook, a lab, or a budget. It works in any web browser, on any device, in more than a hundred languages. PhET Interactive Simulations, and its website is phet.colorado.edu. Is one of the most valuable free resources the internet has ever created.
Spend an afternoon on PhET and the appeal becomes obvious. Educators speak about it with a reverence usually reserved for expensive tools. The simulations are stunningly beautiful, easy to use, and, most importantly, they actually work. They make the invisible visible. They allow a student to build a circuit without burning anything, to investigate the gravity of Jupiter without leaving the room, to watch molecules collide without a particle accelerator.
The Origin and the Mission
Nobel Prize-winning physicist Carl Wieman founded PhET in 2002 at the University of Colorado Boulder. The site was originally an acronym for Physics Education Technology, but it quickly came to encompass much more than that. Wieman’s central mission was that students learn science best when they are free to explore and experiment, rather than being forced to sit and listen.
This founding spirit is evident in every simulation that the team has created. There is nothing on PhET that requires a tutorial. You simply open a simulation and start clicking. Sliders work. Variables change. Cause and effect happen right before your eyes, right in front of you. The simulation is open-ended, meant to encourage exploration rather than lead the student through a predetermined process.
What the Platform Offers
Today, PhET offers more than 125 interactive simulations in physics, chemistry, biology, earth science, and math. The simulations range from basic arithmetic and fractions all the way through to quantum mechanics and nuclear fission. Every simulation is available in more than 121 languages, making PhET truly global in its scope and influence.
The team builds every simulation in HTML5. They run in any modern browser on a computer, tablet, or smartphone. No plugins or downloads are required. A student using a Chromebook in a rural school has the same chemistry lab access as a student at a well-funded private university. This is not secondary to the mission of PhET. This is the mission.
The simulations themselves are very detailed. Physics simulations allow students to manipulate variables such as mass, gravity, friction, and energy in ways that would be impossible or cost-prohibitive in a physical lab setting. Chemistry simulations model the behavior of atoms and molecules at a scale that would be impossible to achieve in a physical lab. Math simulations allow students to manipulate concepts such as fractions, function graphs, and probability in a very tactile way.
The Research Foundation
What distinguishes PhET from the dozens of well-intentioned educational websites that have launched and faded into obscurity is the level of sophistication in the development process. The team designs each simulation in collaboration with education researchers, teachers, and students. The team tests each simulation through recorded student interviews in which the PhET team observes firsthand how students actually use the simulation and pinpoint exactly where the understanding goes awry.
The end result is an educational tool that is not only technically sound but also pedagogically sound. Peer-reviewed studies show that students who use PhET outperform those who rely on traditional instruction. Students who learn using PhET simulations outperform students who learn using traditional teaching methods. The simulations are not a supplement to rigorous learning. They are a method of learning.
For Teachers: A Ready-Made Toolkit
PhET is as much a tool for teachers as it is for students. A free account gives access to hundreds of pre-made lesson plans, lab activities, and homework assignments created and shared by teachers worldwide. The open-source approach to the platform means that every single resource in the library can be downloaded, modified, and shared freely. A teacher in one part of the world can leverage the work of a teacher in another, and all will benefit.
Teachers use simulations in whole-class demonstrations, small groups, independent study, or online courses. During the rapid transition to online learning in 2020, PhET became a critical resource for science educators trying to replicate the lab experience at home. Many educators have never looked back on how they used to do things before.
Even without an account, all of the simulations available on the site are immediately available to anyone with access to a browser and the internet. There are no paywalls, no premium content, no locked-down subscription-only material. PhET is free in the absolute sense of the word.
A Few Honest Limitations
No resource is perfect. The visual aesthetic of PhET, while perfectly functional and easy to understand, looks a bit dated in comparison to the slick interfaces students are used to in educational software and games. Some users have pointed out that the platform is best used in conjunction with teacher-led instruction – the open-ended exploration model is incredibly powerful, but students who are completely new to a subject area may benefit from some structured instruction before exploring a simulation.
The biology library remains smaller than the physics and chemistry collections. The simulations build strong conceptual understanding. However, they cannot replace hands-on experimentation. Students still benefit from handling real materials and observing unpredictable results. They’re a supplement to physical labs, not a replacement.
The Bottom Line
PhET Interactive Simulations is, hands down, one of the most valuable free educational resources available on the internet. It provides an experience that rivals or surpasses many paid platforms, with over twenty years of research-informed development and a dedication to accessibility that is all too rare in educational technology.
Whether you are a teacher trying to make abstract STEM ideas come alive, a student working through material that has not yet clicked, a parent homeschooling your children, or simply an interested adult wanting to understand how a circuit works or what a molecule looks like in motion, PhET has something for you. Open a browser, go to phet.colorado.edu, and choose a simulation that interests you. You won’t be sorry.
PhET is the kind of thing the internet was supposed to be for.
