Recently I purchased the Snap Circuits Jr. kit and was working through the different projects with my daughter. We decided to connect two loads in series circuit, powered by the battery source. The first load was a LED light, the second was a fan (a spinning wheel where you place the plastic blades on top).
With the two loads in series, I turned on the switch. I observe the following which I could not explain.
1) Both loads were operating, however, the first load (LED light) was dimmer than if it were the only load in the circuit. Why? I would expect full voltage available before the first load, and hence full voltage drop across that first load.
2) If I introduced physical resistance to the movement of the second load (the fan) with my finger, the first load (LED light) would become brighter. Inversely, if I removed any physical resistance (finger, the fan blade) such that the wheel spun freely, the first load would become brighter. Why?
In summary, given a series circuit I don't understand why the second load would impact the first? Please help this uninformed dad so my daughter thinks I know everything again!