Electricity v Electronics

The switch in the above circuit, already shows a 'sensor' to 'sense' human activity. This switch however, is the most BASIC of sensor there is. At present, it can only turn the light bulb on or off. The pattern of turning the switch on and off can convey some meaning. Observed over time, it is clear you're using the change in electrical energy to pass a message or a signal. In this case, this is a distinction between electricity and electronics.

"Think of 'electronics' as a subset of 'electrical circuits' that is used to convey information"

There are 2 basic properties of electrical energy that will be useful to you in all the circuits you build. These will help us to prevent a 'Short circuit' and/or troubleshoot problems with the circuit.

"Electricity always follows the path of less resistance"

For example, if I were to create a circuit which also had a wire connected to the ground, the electrical current would travel straight to the ground because it offers less resistance, therefore bypassing the circuit thus creating a "Short circuit"

"All the electrical energy in a circuit must be used"

ultimately this means that the components in your circuit have to consume all of the energy that you put into the circuit. Any extra energy will be converted into heat by the components if there's too much energy, leading to them overheating and stop working.