Physiworld’s
Kelvin
Ask anything about physics — from a quick concept check to a full worked problem. Kelvin explains it clearly, step by step, at whatever level you’re working at. Sign in and it picks up from what you’ve already done.
Ask anything about physics — from a quick concept check to a full worked problem. Kelvin explains it clearly, step by step, at whatever level you’re working at. Sign in and it picks up from what you’ve already done.
Hi — I’m Kelvin, your physics professor. How can I help you today?
Kelvin can make mistakes — double-check anything important.
Signing in lets Kelvin answer your questions — and tailor them to the lessons and quizzes you’ve done. Free to start, no card needed.
A physics teacher who already knows where you are.
Kelvin is Physiworld’s built-in AI physics teacher. Ask it anything — a quick concept check or a full worked problem — and it explains step by step, with proper maths, at whatever level you’re working at. Built on the same IGCSE, GCSE, AP Physics 1 and NGSS curriculum as the rest of Physiworld.
Questions about Kelvin
What is Kelvin?
Kelvin is Physiworld’s built-in AI physics tutor. You can ask Kelvin any physics question, ask it to explain an idea your way, work through a problem step by step, or tell you what to study next. Because Kelvin knows the Physiworld curriculum and your own progress, its help is tailored to exactly where you are.
Is Kelvin free to use?
Yes — you can start chatting with Kelvin for free once you create a free Physiworld account. A larger daily message allowance and deeper features are available with the optional Physi+ upgrade.
How is Kelvin different from a general AI chatbot?
Unlike a general chatbot, Kelvin is grounded in the Physiworld physics curriculum and your own learning data — the lessons, quizzes and challenges you’ve done and the topics you’re weakest on — so it can point you to the exact lesson or quiz to do next, not just give a generic answer.
Which physics courses does Kelvin cover?
Kelvin covers the same ground as Physiworld: the Cambridge IGCSE (0625) syllabus, with help that also prepares you for GCSE, AP Physics 1 and NGSS-aligned courses, across all ten physics topics.