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What is PhET?

PhET is a collection of free interactive science and math simulations from the University of Colorado Boulder. Rather than reading about a concept, you manipulate it: drag a skater along a track to see energy transform, adjust a circuit to watch current change, or move charges to build an electric field. The simulations run in a browser or as downloadable apps and cover physics, chemistry, biology, earth science, and math, mostly at middle school through early college level.

PhET

What it's good for

• Classroom demonstration: project a simulation and change one variable at a time while students predict what happens next.
• Homework and self-study: learners can repeat an experiment as often as they like without lab equipment or safety limits.
• Conceptual gaps: if a textbook explanation isn't landing, a simulation often makes the invisible visible — forces, fields, energy, molecules.

Trade-offs to know

Simulations are models, not reality. They simplify or omit factors such as friction, air resistance, or measurement error, so they build intuition rather than replace hands-on lab work or precise data collection. Some titles assume prior knowledge and are best paired with a worksheet or guiding questions.

Next step

Pick the topic you're teaching or studying, open one simulation, and change a single variable while writing down a prediction first. If you want structured activities, look for the teacher-submitted resources attached to many simulations. For a different style of guided practice, ExploreLearning Gizmos offers similar interactive labs, though it is a paid subscription rather than free.

How can I use PhET simulations in my classroom lesson plan?

PhET is best used as a demonstration-and-discovery layer inside a lesson, not as a replacement for instruction. At PhET, simulations are interactive models for physics, chemistry, biology, earth science and math, so they fit lessons that need variables students can change and observe immediately.

A practical lesson structure

1. Pre-teach the concept briefly. Give students the vocabulary and the system they are about to manipulate (for example, forces, circuits, or gas laws).
2. Run a guided exploration. Project one simulation and ask prediction questions before changing a slider: "What will happen to the pressure if we reduce the volume?"
3. Let students explore in pairs. Have them record what they change, what they observe, and one pattern they notice.
4. Debrief with a whole-class model. Use the simulation again to confirm or correct the patterns students found.

Matching simulations to lesson goals

What to watch for

Simulations simplify real systems, so students can mistake the model for reality. Pair each activity with a question that connects it back to the physical world, and check that students can explain the underlying rule rather than just describe what they saw on screen.

A useful next step is to pick one upcoming topic, find a matching simulation, and write three prediction questions plus one debrief question before class. That keeps the technology tied to your learning objective instead of becoming a standalone activity.

Are PhET simulations free to use for students and teachers?

Yes. PhET simulations are free to use for students and teachers. You can open them in a browser without paying, and use them in class, at home, or in a study group. The project is run by the University of Colorado Boulder and offers simulations across physics, chemistry, biology, earth science and math at PhET.

What “free” means in practice

• No purchase or subscription is needed to run the simulations.
• Teachers can project them, assign them, or build lessons around them.
• Students can use them for homework, revision, or self-study.
• The simulations are designed to be used directly online, so a laptop, tablet or phone with a browser is usually enough.

Where the trade-offs are

Free access does not mean every possible feature or language is equally developed. Some simulations have more supporting teacher materials than others, and the experience depends on your device and connection. If you need offline use, check whether a downloadable version is available for the specific simulation you want. If you teach in a language other than English, check the translation coverage for that simulation before planning a lesson around it.

A useful next step

Pick one topic you are teaching or studying this week, open the matching simulation, and run it once yourself before sharing it. Note whether it works on the devices your students actually use, and whether the on-screen instructions are clear without extra explanation. That five-minute test tells you more than a general review.

For a broader set of free teaching resources, you can also compare with OER Commons or CK-12, but PhET itself does not require payment for student or teacher use.

What subjects and grade levels are covered by PhET simulations?

PhET covers science and math through interactive simulations rather than a fixed curriculum. Its subject range spans physics, chemistry, biology, earth science, and mathematics, with simulations usable from upper elementary through university-level courses.

H3 Subject areas

• Physics: motion, forces, energy, waves, electricity and magnetism, optics, quantum phenomena.
• Chemistry: atomic structure, molecules, reactions, states of matter, acids and bases.
• Biology: cells, genetics, natural selection, neuroscience basics.
• Earth science: plate tectonics, glaciers, greenhouse effect, energy forms.
• Math: number sense, fractions, graphing, functions, calculus foundations.

H3 Grade levels PhET does not label every simulation with a single grade. Instead, difficulty varies by simulation. Many are designed for middle and high school; some are suitable for upper elementary, while others target introductory university courses. The best guide is the simulation's own description and the level of math it assumes.

H3 How to choose

• Elementary: pick concrete, visual simulations with minimal reading.
• Middle school: use guided worksheets and prediction activities.
• High school: pair simulations with lab-style data collection.
• University: use advanced simulations for concept demonstrations and homework.

A practical next step: browse by subject on PhET and check each simulation's stated grade range before assigning it. For a concrete example, a physics teacher introducing circuits might use a basic circuit sim in middle school, then the same sim with quantitative measurements in high school.

Can I run PhET simulations on a Chromebook, tablet, or smartphone?

Yes. PhET simulations run in a web browser, so a Chromebook, tablet or smartphone can generally open them without installing desktop software. The practical limits are screen size, input method and browser support rather than the device category itself.

PhET is built around interactive HTML5 simulations, which is why the same simulation can load on a laptop, a school Chromebook, an iPad or an Android phone. On a Chromebook, the experience is closest to a desktop: a trackpad or mouse makes dragging sliders, rotating objects and reading labels much easier. On a tablet, touch works well for simulations that involve dragging, tapping and tilting, but fine control can be harder. On a smartphone, the simulation may load but feel cramped; many simulations were designed for a wider canvas, so labels, graphs and controls can become small.

A useful decision rule:

• Chromebook or laptop: best default for classroom work, homework and any simulation with graphs or multiple panels.
• Tablet: good for touch-friendly simulations, demonstrations and one-to-one use; add a stylus if precision matters.
• Smartphone: fine for a quick look or a single simple simulation, but not ideal for extended exploration or data collection.

As a next step, open one simulation you plan to use and test the specific interactions it requires — dragging a slider, reading a graph, or entering a value — on the actual device. If the controls are hard to hit, switch to a larger screen rather than assuming the simulation is broken. For school settings, a Chromebook with a mouse remains the most reliable combination.

How do I access or share a specific PhET simulation with my students?

PhET simulations live on individual pages at phet.colorado.edu, so sharing one with students means sending them the link to that specific simulation rather than the site homepage. Open the simulation you want, copy the page URL from your browser, and share it through your class platform, messaging app or email. Students then click the link and the simulation runs in their browser — no account or download required, and it works on Chromebooks, laptops and tablets.

Finding the right simulation first

Browse by subject (physics, chemistry, biology, earth science, math) or use the search box. If you already know the topic — say, projectile motion or balancing chemical equations — search is faster. Each simulation page also lists related simulations, which helps when you want a matching pair for a lesson.

Ways to share

• Direct link: paste the simulation URL into Google Classroom, Canvas, Schoology, a slide deck or a class chat. This is the simplest and works for any device.
• Embed: many learning-management systems let you embed a page in an iframe, so students stay inside your course. Test the embed before assigning it, since some platforms block iframes.
• Offline or low-bandwidth use: PhET offers downloadable versions of many simulations for situations where the internet is unreliable. Check the individual simulation page for a download option.
• Whole-class display: project the simulation and drive it yourself for a demo, then share the link so students can explore on their own devices.

A practical next step

Before assigning, open the link in a private browser window to confirm it loads without your login, then decide how students will record results — a shared Google Doc, a printed sheet or a screenshot pasted into your LMS. If you want a ready-made activity rather than just the simulation, PhET's teacher resources include contributed lesson plans and tips you can adapt.

For a broader set of vetted interactive math and science tools, PhET is the natural starting point; Concord Consortium and CK-12 offer complementary simulations and flexbooks if you want alternatives for a specific topic.