Impulse is an interactive physics simulation of collisions with spheres, designed to help learners better understand the concept of force in Newtonian mechanics. In four modes (target impact from rest, target impact from motion, parallel spheres, fan), they investigate how the strength and duration of the impact, as well as the mass of the sphere, influence the change in velocity and discover the relationship F⋅Δt=m⋅Δv. Informative arrows for initial, additional, and final velocities support a deep understanding of dynamics and connect to familiar teaching concepts from lower secondary school.