World 3 · Reaction Rates · 6 min · PROCatalysts
A lower hill, the same valley
PRO · Particle Lab
World 3: Reaction Rates is part of PRO
The first world of Particle Lab is free. PRO opens the other 17 lessons in 4 worlds — simulations, quizzes and all.
PRO includes
- All 26 labs — every world, every lesson
- Practice exams and certificates
$8.33/mo, billed yearly ($99.99) · or $39.99 monthly