PhET Simulations for Students | Science, Mathematics and Virtual Labs

PhET Interactive Simulations for students make invisible or difficult ideas easier to explore. Instead of only reading that a closed circuit allows current, a learner can build a simple virtual circuit and see the bulb respond. Instead of memorising that two fractions are equivalent, a pupil can adjust a visual model and compare the shaded quantities.

This can be an excellent learning experience—provided that the child does more than move sliders until the picture looks satisfying. Simulations are models, and a model must be interpreted. The learner still needs to predict, observe, explain and check what happens in real experiments or school questions.

Parents searching for PhET simulation, free science simulations, PhET circuit construction kit, PhET fractions, or virtual science laboratory for students need practical examples and sensible boundaries. This guide shows how Singapore Primary and Secondary students can use PhET for Mathematics and Science without treating the screen as a substitute for scientific evidence or written reasoning.

Quick answer: PhET Interactive Simulations is a University of Colorado Boulder project offering free interactive Mathematics and Science simulations on the web. Many have downloadable or app-based routes for offline use. The most useful routine is predict → manipulate one condition → observe → explain → test a new situation. The simulation helps build a concept; the student must still demonstrate independent understanding.

What Is PhET?

PhET began as a project for interactive teaching and learning in Physics and has expanded across Science and Mathematics topics. It provides visual simulations with controls, objects, measurements and representations students can manipulate.

The official PhET teaching resources encourage teachers to guide exploration productively. Students should not simply follow a long recipe of clicks and copy the final screenshot.

Different PhET simulations support different age levels. Some illustrate basic fractions, area or motion; others involve atomic structure, advanced Electricity or more demanding physical models.

A parent should therefore select the individual simulation based on the concept being studied, not assume that everything in the catalogue is suitable for every Primary 3 child.

The key advantage is that the learner can repeatedly vary a model and see consequences that might be difficult to demonstrate quickly with physical materials.

Are PhET Simulations Free? What About Offline Use?

PhET provides free access to its simulation library on the web. The official offline access page lists additional ways to use simulations without a normal internet connection.

On Windows and macOS, the project offers a desktop application with supported HTML5 and Java simulations and translation resources. Some older Java content requires additional compatibility provisions; unsupported Flash simulations are not suitable for modern browsers.

There are also mobile app routes for Android and iOS, with availability and purchase or licensing conditions differing from the free web experience. PhET’s official offline page describes options for downloading individual HTML5 simulations and supported mobile-app access.

Do not assume that downloading the web page automatically grants every app feature or that every simulation runs on every device. Check the specific platform instructions.

For a first lesson, the web simulator on a capable computer is a sensible starting point. The learning goal does not require a paid app.

Start With a Question, Not a Slider

A child opens a simulation and begins clicking. The movement is interesting, but it may not be learning. Before the first interaction, provide a specific question.

For a circuit: Will the bulb light if the switch is open? Why? For fractions: Can 3/4 and 6/8 represent the same portion? For area: Can two shapes have the same area but different perimeter?

Ask the student to make a prediction in words. A prediction makes the child’s existing idea visible. If it is wrong, the discrepancy provides an opportunity to revise understanding.

Next, change just one important condition while keeping the other features of the setup as comparable as possible. Record what actually happened in the model.

Finally, make the student explain the result without referring to the computer interface. If the learner cannot explain the observation, the activity needs a short conceptual discussion.

This sequence is useful in a classroom, home lesson or three-student tutorial.

Worked Example 1: Fractions Intro and Equivalent Fractions

Open PhET Fractions: Intro. This simulation illustrates fraction representations and relationships.

A useful question is whether 3/4 and 6/8 represent the same fraction of a whole. Three quarters means three of four equal parts; six eighths means six of eight equal parts.

To verify arithmetically, multiply the numerator and denominator of 3/4 by 2. That gives 6/8. The relative portion of the whole remains unchanged.

Ask the learner to explore suitable visual fraction models in the simulation. The shaded regions should represent equal portions when the wholes are the same size and the partitions are equal within each whole.

Now compare 3/4 with 3/8. The numerators match, but the portions do not. Three eighths is smaller than three quarters when the whole has the same size.

The correct lesson is not “a fraction with more pieces is larger”. It is that a fraction describes a relationship between selected equal parts and the total number of equal parts.

Close the simulation and try another example: 2/3 = 4/6, while 2/3 is not equal to 2/6. The child should explain the relationship without relying on the visual controls.

Worked Example 2: Area Builder and Perimeter

Use PhET Area Builder to compare shapes and their areas and perimeters.

Begin with a rectangle made from equal unit squares. Suppose it is 6 units long and 4 units wide. The area is 6 × 4 = 24 square units. The perimeter is 2(6 + 4) = 20 units.

Ask the pupil to create or investigate another arrangement with the same number of unit squares but a different boundary. A 3-by-8 rectangle still has an area of 24 square units, but its perimeter is 2(3 + 8) = 22 units.

This is a powerful counterexample to the assumption that equal area must mean equal perimeter.

The student should distinguish what the visual squares represent. Each square contributes one unit of area. The exposed outer edges contribute to the perimeter. Internal edges between adjacent squares do not count as part of the exterior boundary.

Now ask the child to predict the result before building a third shape. Mathematical thinking becomes visible when the student can explain the formula and apply it away from the screen.

For Primary Mathematics, this helps connect concrete arrangements to abstract calculations and proper units.

Worked Example 3: Build a Simple Electric Circuit

Open the official Circuit Construction Kit: DC. Select an introductory screen if appropriate for the learner.

Build a simple circuit with a battery, two wires and a bulb so that a complete conducting loop is formed through the lamp. In the model, a correctly connected bulb can light.

Now change one condition: interrupt the path with an open switch or disconnect a wire. Ask the student to predict what happens. With the conducting path broken, current through that simple series path stops and the bulb goes out.

The important Science explanation is a complete conducting path is needed for current in this circuit. The battery is still present when the switch opens; opening the switch does not destroy its stored chemical energy.

Let the child close the switch and describe why the bulb can light again. Avoid an overly vague explanation such as “electricity likes closed circles”.

A further activity can compare the model’s treatment of adding another bulb in series and ask what changes, but this should be taught at the appropriate subject level with the circuit conditions stated carefully.

A simulation is safer for exploring virtual arrangements than experimenting with actual household mains electricity. Students should never imitate a circuit activity by opening power outlets or connecting household electrical wires.

What a PhET Circuit Shows—and What It Does Not

The simulation uses an educational model to make electrical relationships visible. The moving charges, circuit connections and measured values can help a student understand a process that cannot be observed directly in a classroom wire.

But the size, movement and display of charge symbols are not necessarily a literal picture of individual electrons in a real copper wire. Educational visualisations simplify reality.

When using this model, ask which observations the virtual environment is designed to illustrate and which details are omitted. For instance, real wires and batteries involve additional physical conditions that may not be represented in a simple circuit.

A teacher may also explain how current, voltage and resistance relate, where appropriate to the syllabus. A correct voltage measurement is not the same as a bulb’s brightness.

The learner should treat the virtual apparatus as a conceptual tool and compare claims with standard scientific explanations or supervised physical experiments.

See How Primary Science Works for a wider foundation in observation and explanation.

Worked Example 4: Energy Skate Park and Conservation of Energy

Open PhET Energy Skate Park. The model lets learners explore motion and different forms of energy.

Consider a skater beginning high above the lowest point of a track. In a suitable idealised setting with negligible friction, gravitational potential energy decreases as the skater descends and kinetic energy increases.

At a lower position, the skater typically has greater speed than at the higher starting point, provided the assumptions of the comparison are met. The energy has changed form.

When friction is included, some mechanical energy is transferred into thermal energy. It is incorrect to say that energy simply disappears because the skater eventually slows.

Ask the learner to identify which energy transfers are represented in the display and how the situation would be interpreted under the conservation principle.

Do not claim that a real skater is perfectly frictionless or that the simulation covers every physical effect. The model isolates selected variables to make a principle easier to examine.

Finish by asking the student to explain the movement of a swinging pendulum in words, identifying where kinetic and gravitational potential energy are relatively greater. This transfer activity tests the conceptual relationship beyond the original animation.

Worked Example 5: Balancing Chemical Equations

For suitable Secondary learners, use PhET Balancing Chemical Equations.

A balanced chemical equation conserves the number of atoms of each element across the two sides of the equation. That is related to conservation of mass in the usual chemical reaction model.

Consider 2H₂ + O₂ → 2H₂O. On the left there are four hydrogen atoms and two oxygen atoms; on the right there are also four hydrogen atoms and two oxygen atoms.

The student must distinguish a coefficient from a subscript. Changing the coefficient changes how many molecules or formula units are represented; changing a subscript changes the chemical formula itself.

Use the simulation to observe whether the count of each element is balanced, then require a written explanation without the animation.

For younger pupils who have not learnt chemical equations, this example may be inappropriate. The correct learning resource is the one that fits the current school topic and student’s conceptual readiness.

A Good Simulation Changes Only One Important Condition

Suppose a virtual experiment allows the student to change the mass of an object, the applied force and friction. If all three are changed simultaneously, the learner may not know which change produced the new motion.

A better comparison varies one intended factor while holding other relevant conditions fixed. This echoes the scientific idea of a fair test.

Ask the student to record: Initial condition, Changed variable, Predicted effect, Observed effect, and Explanation.

The goal is not to recreate an industrial laboratory in perfect detail; the goal is to practise reasoning about the relationship between an input and a result.

Where the simulation itself combines multiple influences, the tutor should help the student recognise that the interpretation may be more complicated than a one-variable rule.

This habit supports Science practical skills and interpreting data-based questions at Secondary level.

Evidence, Observation and Model Output Are Different Things

A learner might say, “I proved the circuit principle because the screen displayed it.” That is too strong. A computer programme behaves according to its model and programmed rules.

The simulation can illustrate, support or help investigate a scientific explanation. It cannot automatically substitute for a mathematical proof, real experimental evidence or evaluation of the model’s assumptions.

Teach three distinctions: real-world observation, simulation output, and scientific explanation. These may agree, but they are not identical categories.

For example, in a virtual circuit, a correctly arranged connection may produce a bulb animation. A real experiment can include contact resistance, a faulty component or a depleted battery. Those additional details may create a different outcome.

The learner should ask what the model holds constant or simplifies. This is a mature scientific habit, not a reason to dismiss simulations.

Well-used simulations encourage better questions about the world; they do not remove the responsibility to check claims.

PhET for Primary 3 and Primary 4 Science

Formal Science learning in Singapore’s Primary curriculum begins at Primary 3. Younger Science learners usually need clear vocabulary, observation skills, simple explanations and opportunities to connect concepts with familiar objects.

Select beginner-friendly simulations and limit the number of controls introduced at once. A parent can ask the child to predict whether a bulb lights in a simple closed circuit model or what happens when the shape of an area model changes.

Do not begin with a university-level Physics simulation simply because the child enjoys pressing controls.

After a short exploration, ask for one complete explanation in ordinary language. For example: “The bulb went out because the switch broke the conducting path.”

If the student can explain one connection and answer a fresh question, the activity may be enough. More animation is not necessarily more learning.

PhET for Primary 5 and Primary 6 Science

At Primary 5 and Primary 6, learners face a growing need to explain relationships and reason about unfamiliar situations. Appropriate virtual activities can strengthen concepts, but students still need to practise the specific question forms they encounter in school.

Choose a small topic such as Electricity or Heat when it fits the teacher’s sequence. Begin with the syllabus concept, explore one model and then practise a related open-ended question.

Avoid teaching a simulation as though every control and advanced option were examinable. Some features may go beyond the level or use simplifications different from the language expected at school.

A strong session ends with the student writing a cause-and-effect explanation using the correct scientific terms.

PSLE Science preparation is not completed by a collection of colourful screenshots. A learner needs accurate concepts, question interpretation and independent response practice.

PhET for Secondary Science and Mathematics

Secondary students can work with more complex relationships, including forces, energy, circuits, atoms, molecules, functions and data, depending on their subject level and syllabus.

A student studying electrical resistance might explore a suitable resistance simulation, but should still calculate relationships and interpret units under the assumptions taught. One who understands energy transfer should explain how the observations relate to the conservation principle.

The platform may also provide interactive Mathematics models that help with fractions, probability and representations. The learner should move between the visual model and written expressions.

Do not assume a foreign platform’s topic list matches the exact G1, G2 or G3 curriculum. Choose content according to the student’s actual subject and assessment objectives.

For the wider transition into algebra, see Secondary 1 Mathematics Tutor Clementi.

PhET Offline, Accessibility and Translations

The official PhET global resources page describes online and offline access, accessibility-related features and translations in many languages.

Accessibility varies among individual simulations. Some offer keyboard access, screen-reader support, description or other inclusive features; users should check the page for the specific simulation instead of assuming identical accessibility throughout the library.

For bilingual learning, choose a supported simulation language carefully. A translated interface can help students understand buttons and terms, but the learner still needs to know the scientific vocabulary required by their class.

An offline activity may suit a location with unreliable connectivity, provided the required simulation has been downloaded and tested in advance.

Whether the app is online or offline, a clear worksheet and thoughtful teacher guidance remain essential.

A Twenty-Minute Simulation Learning Routine

Use a small and repeatable inquiry structure:

Minutes 1–4: State one question and write a prediction.
Minutes 5–9: Explore the simulation, changing one important variable.
Minutes 10–12: Describe what the model visibly did.
Minutes 13–16: Explain the result using correct Mathematics or Science.
Minutes 17–20: Close the simulation and solve a related new question independently.

In a three-student group, rotate predictor, controller and evidence checker. The predictor records what should happen; the controller runs a fair comparison; the checker looks for unsupported conclusions.

If the students disagree, return to the model’s assumptions and the underlying concept. The disagreement is an opportunity for reasoning rather than a problem to hide.

Keep the task short enough that the educational question remains more important than exploring every feature.

Common Simulation Mistakes

Random clicking: no clear question guides the activity. Repair by setting one prediction before exploration.
Changing several variables: the cause of the result is unclear. Repair by controlling a smaller number of factors.
Copying a virtual answer: the child cannot explain the model. Repair by requiring a written description.
Treating symbols literally: the animation is mistaken for the full physical mechanism. Repair by discussing simplifications.
Assuming a screenshot is proof: observed patterns are mistaken for universal mathematical or scientific justification. Repair by adding valid reasoning.
Ignoring level alignment: a Secondary model is used before foundational ideas are taught. Repair by selecting a suitable simulation.
Misreading units and scales: displayed values are interpreted without context. Repair by checking quantities and dimensions.
Using simulations instead of approved assessments: the student expects exam access to a web tool. Repair by practising under the actual examination conditions.

The first useful diagnosis is whether the mistake concerns the concept, the experimental comparison, the interpretation or the independent explanation.

PhET Compared With Scratch, Desmos and GeoGebra

Scratch for Students helps learners build their own interactive programmes. Desmos for Students makes mathematical graphs easy to explore. GeoGebra for Students supports dynamic mathematical constructions.

PhET is especially useful when the learner wants to interact with a prepared scientific or mathematical model and investigate its behaviour.

The distinction matters. A Scratch animation of a circuit is a programme written by a learner. A PhET circuit simulation is an educational model created for exploring specified electrical principles. Both can be useful, but neither guarantees that the user understands the physics.

Choose the tool according to the learning question, not the number of interactive controls it offers.

Frequently Asked Questions

Are PhET simulations free for students?

The web simulations are freely accessible. PhET also documents offline desktop and mobile-app routes, with different compatibility and purchasing or licensing arrangements.

Can I use PhET on an iPad?

Supported simulations may run through compatible browsers or app routes. Check the official offline and platform guidance for the specific device and simulation.

Is PhET good for PSLE Science?

Age-appropriate simulations can illustrate selected concepts, but they do not replace MOE-aligned content, open-ended answers or school assessment practice.

Can PhET replace a real Science experiment?

Not entirely. A virtual model can clarify relationships and allow repeated comparisons, but real experiments introduce observation, measurement error, equipment handling and safety considerations not necessarily present in the model.

What should students write after using a simulation?

A short prediction, what was changed, what was observed, an explanation and one limitation of the model provide a useful record.

Can PhET teach Mathematics?

Yes. Its catalogue includes Mathematics simulations such as Fractions: Intro and Area Builder. Students should still calculate and explain without visual cues.

Does a PhET animation prove a scientific theory?

No. A simulation illustrates the behaviour of a model based on assumptions. The model can support understanding but does not replace evidence and explanation.

How can parents check whether the lesson worked?

Ask the child to apply the same concept to a fresh situation with the simulation closed. A clear, correct independent explanation is a stronger outcome than a completed interactive activity.

Official Sources and eduKateSG Learning Routes

The lasting lesson: use simulations to ask better questions, not to avoid explaining answers. The value is what the learner can observe, justify and apply independently after the screen is closed.