In this study, we have become a little more expert in physics – thinking about electricity. We have been building on our knowledge of open and closed circuits to test hypothesis about the brightness of the bulb. We made 3 circuits. We started with a basic circuit with 2 wires, a bulb and a battery. We thought about the cause and effect on the dependent variable, the brightness of the bulb, as we changed the independent variables, how many batteries and bulbs the circuit had.