This Ohm's Law simulator will show you how voltage, current, and resistance are related. Move the sliders to change V (voltage) and R (resistance). The Stage uses a script to calculate I (current) based on the equation V = IR. The light bulb turns on when it gets enough current!
Learn how variables work in this Ohm's Law simulator! From Chapter 5 of "Learn to Program with Scratch" (nostarch.com/learnscratch), by author Majed Marji.