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Physics you can run.
Ideas that click.

Physics taught with three of the best-proven methods in learning science. Free for students, parents and anyone who just wants to understand how the universe works.

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How Physiworld works

Why it works

1

Predict

before you’re told

Every lesson opens with a question. You commit to an answer, then run the simulation and see for yourself whether you were right.

★★★★★
“Being able to change variables and immediately see what happens makes physics feel much less abstract.”
IGCSE Physics student
2

Recall

instead of rereading

Exam-style questions make you pull the idea back out of your head, which is what makes it stay. Every answer comes with the full worked solution.

★★★★★
“Physics started making a lot more sense when I stopped just memorising equations.”
AP Physics 1 student
3

Review

right before you forget

Every question you miss comes back after 3, 7 and 21 days until you get it right. A few minutes on your own mistakes beats rereading notes.

★★★★★
“Sometimes seeing the same concept presented differently is all it takes.”
GCSE student
What are you studying?

Get started – for free

Every point of the syllabus, mapped to the lesson that teaches it.

IGCSECambridge 0625 GCSE AQAPhysics and Combined GCSE EdexcelPearson Edexcel GCSE OCRGateway and 21st Century AP Physics 1College Board AP Physics 2College Board NGSSHigh school General physicsA-level, IB or just curious

All questions are original. Physiworld is not affiliated with Cambridge Assessment, AQA, Pearson Edexcel, OCR, the College Board or Achieve, Inc. AP® is a trademark of the College Board; NGSS® of Achieve, Inc.

Built to be checked

Nothing here you have to take on trust

100+Lessons

Each one built around a simulation you run yourself.

250+Quizzes

Exam-style, with a worked solution for every answer.

350+Practice challenges

Exam problems, each in several versions with new numbers.

€0To learn

Every lesson, quiz and challenge. No card, no time limit.

Pricing

Learn it free. Walk into the exam ready.

The whole course is free, for good. The exam pass is what you add for the final stretch: real exam practice under exam conditions, your written answers marked like the real thing, and every mistake you make brought back until it sticks.

Free

Learn the whole course
0EURforever
  • Every lesson and simulation
  • Every quiz, with worked solutions
  • A sample mock exam
  • Review of your latest topic
  • Ask Kelvin every day
Join now for free
Best for the exam

Exam pass

For this exam season
29EURone-time
  • Mock exams, theory papers and mixed practice sets
  • Kelvin marks your written answers against the mark scheme
  • Every mistake, in every topic, back for review
  • Practice versions of every challenge
  • Many more questions to Kelvin, every day
Get the exam pass

Secure checkout with Stripe Change your mind within 14 days No lock-in

Monthly and lifetime plans too. See all plans

Kelvin, your AI tutor

A tutor that makes you think, not copy

Ask anything in physics, in your own words. Every answer follows the same three moves, and the last one is always yours.

  1. The idea first. Plain words before any formula.
  2. A question back. Real numbers, real units, your turn.
  3. Checked, one step further. Your answer confirmed, the next idea opened.
Try Kelvin
If gravity pulls everything at the same rate, why does a feather fall slower than a hammer?
Kelvin · 1Gravity gives both the same acceleration. The difference is air resistance: the feather has a lot of surface for very little weight, so drag soon balances it. On the Moon, with no air, they land together.
Kelvin · 2Try this: a 2 kg ball falls and feels 5 N of drag. What is its acceleration?
Weight is 2 × 9.8 = 19.6 N. 19.6 − 5 = 14.6 N, so a = 14.6 ÷ 2 = 7.3 m/s².
Kelvin · 3That’s it: resultant force first, then F = ma. As the ball speeds up the drag grows, so what happens to its acceleration?

An example written to show how Kelvin answers. Not a real student’s chat.

Frequently Asked Questions

Common questions

For your exam, or just for your curiosity.

Physiworld

What it is and what it costs

What is Physiworld? +
Physiworld is an interactive way to master physics, for anyone who has ever wondered how the world works, whether or not there is an exam at the end of it. Ten modules, from Dynamics and Gravity to Optics, Electromagnetism, Nuclear Physics and Astrophysics, are built as units of short lessons, each around a simulation you run and change yourself. Units close with a quiz, every mistake comes back for review, and your mastery is tracked point by point against your syllabus.
Is Physiworld free to use? +
Yes, to learn. Every lesson, every simulation and every unit quiz is free with an account, and no card is asked for at any point. Review of your latest topic and asking Kelvin, the AI tutor, every day are free too.

Physi+ is the optional exam layer: 21 mock exams, 9 theory papers and 6 mixed sets, Kelvin marking your written answers against the mark scheme, review of every mistake in every topic, 300 questions a day to Kelvin, and the practice versions of every challenge.
What does Physi+ cost? +
The Physi+ exam pass is one payment of 29 EUR (29 USD, 25 GBP or 299 SEK) and is valid until 31 July, through the May/June exams. There is also a monthly plan and a lifetime option. Every price is on the public pricing page, so you can see it before you make an account.

If you're just starting

No background needed, whatever your course

Do I need to be good at physics or maths to start? +
No. You need to be curious, and that is the whole entry requirement. Every topic opens with a question you can answer from everyday life, such as why ships float or why the Moon does not fall down, and the maths arrives only once you already know what it is for. People start here having never passed a physics test in their life.
I'm not studying for an exam — is Physiworld still for me? +
Yes, and you are not an edge case. Adults who dropped physics at school, people who got curious after a documentary, students years away from an exam and teachers borrowing the simulations all learn here. Nothing is locked behind picking a syllabus: choose General physics when you start, open a lesson, and stop when you have had enough. Your progress is kept either way.

If you have an exam

IGCSE, GCSE, AP Physics 1, NGSS — or any other course

Does Physiworld cover IGCSE, GCSE, AP Physics 1 and NGSS? +
Each one has a public syllabus map that shows every point against the lesson that teaches it and, once you are signed in, your mastery on it. Cambridge IGCSE (0625) is mapped section by section, with questions tagged Core or Supplement. GCSE has one map for AQA, Edexcel and OCR, with each board's references, and it names what is not taught yet. AP Physics 1 is mapped unit by unit. NGSS is mapped too, but not every performance expectation is covered yet, and the map shows which ones are.
Physiworld is an independent study resource and is not affiliated with, endorsed by, or involved with Cambridge Assessment, AQA, Pearson Edexcel, OCR, the College Board or Achieve, Inc. AP® is a trademark of the College Board; NGSS® of Achieve, Inc.
My syllabus is none of those — can I still use Physiworld? +
Yes. Physiworld teaches physics, not one exam board’s version of it. Forces, energy, waves, circuits and the atom are the same physics in A-level, IB, a national curriculum or a first-year university course; what changes between syllabuses is the order, the depth and the section numbers.

Pick General physics when you start, open the topics your course covers, and every simulation, quiz and worked solution works exactly as it does for anyone else. What you will not get for an unlisted syllabus is a section-by-section map or questions tagged with its codes.

Still have questions? Reach out!

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