Get a 5 on Your AP Exam
We guarantee you'll get a 5. And if you don't? Well, at least it didn't cost you anything, because reef.science is completely free. Always has been, always will be.
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Practice Problems
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AP-Relevant Courses
What we cover
We are not going to pretend we cover every AP exam under the sun. We are focused on the STEM exams where we can genuinely help, and we want to be upfront about exactly where things stand.
AP Physics C: Mechanics
Strong coverage
24 question generators covering kinematics, Newton's laws, energy, momentum, rotation, and oscillations. Full course content with 49 narrative lessons across 10 modules. Four interactive simulations for hands-on exploration.
AP Chemistry
Growing
27 question generators spanning stoichiometry, thermochemistry, kinetics, equilibrium, acid-base chemistry, and electrochemistry. We are adding new generators regularly and building out course lessons.
AP Calculus AB/BC
Course content in development
Our Math Foundations course covers 80 concepts including limits, derivatives, and integrals. Dedicated calculus generators are on the roadmap. In the meantime, the physics generators are calculus-based and will give your calc skills a serious workout.
Why practice with us
Those AP prep books give you 300 problems and call it comprehensive. You burn through them in a week, start recognizing the answers by page number instead of by understanding, and then panic because you have nothing left to practice with before the exam. We generate a new problem every time you click. For free. We will say it again: for free.
Every problem comes with a detailed explanation that walks you through the solution step by step. Not just "apply conservation of energy" but the actual math, the actual reasoning, the actual "here is where most students mess up" warnings. You get the kind of feedback a great TA would give you, except this TA is available at 2 AM the night before your exam and does not judge you for cramming.
Simulations that actually teach
We have four interactive PhET-style simulations that let you play with physics concepts in real time. Load a beam and watch the shear and moment diagrams update live. Build vectors and see how components add up. Resolve forces in 2D and watch the equilibrium conditions change. Explore moments by dragging forces around a pivot point.
These are not animations you passively watch. You drag, you adjust, you break things, and you build intuition that sticks. Physics makes a lot more sense when you can poke at it. Try the simulations and see what we mean.
Work in progress, made with love
We should be honest with you: reef.science is still being built. We are a small team that cares a lot about making STEM education accessible, and we are adding new content and features as fast as we can. Some courses have deep coverage already, others are just getting started. Some features are polished, others are held together with enthusiasm and good intentions.
Here is what is coming soon: more chemistry generators, dedicated calculus problem sets, additional interactive simulations, and an AI tutor that can walk you through problems step by step. We ship updates regularly, so check back often. And if there is something specific you wish we had, hit the feedback button and tell us. We read every single submission, and student feedback directly shapes what we build next.
Shipping fast
New generators and features land every week. The platform you see today will be bigger and better next month.
Quality obsessed
Every generator goes through degeneracy testing to make sure problems are solvable, unique, and pedagogically sound.
Student-driven
Your feedback shapes the roadmap. If you need something, tell us and there is a good chance it will show up in a future update.
The three most important F words
A lot of AP prep feels like it was designed to stress you out and separate you from your money. We think it should be the opposite. You are a high schooler taking on college-level material, and that is already impressive. You deserve tools that respect your effort and your budget.
Education should be free, fun, and fantastic (the three most important F words).
That is not a marketing slogan. It is literally why this platform exists. We are not going to charge you for practice problems. We are not going to make studying feel like a chore. And we are going to keep making this thing better until it is genuinely fantastic. You have our word.
Start AP prep now
Grab your calculator, pick a topic, and start solving. You have literally nothing to lose because the whole thing is free.
Zero dollars. Infinite practice. Not a bad deal.
Found a problem or have an idea? Use the feedback button (bottom right on every page) to let us know. We read every submission.