I am a retired grandfather homeschooling my 2 granddaughters. My 5th grade student has a science lab on series and parallel circuits. She is to build a simple series circuit with lamps and batteries. The only problem is that the sight the school uses does not show the lights getting dimmer when more lights are added to the circuit. I am trying to use this site to show her, the only problem is I cannot get the lamp to light when I hook it to the battery. What am I doing wrong?