Starting to understand potential difference

Making sense of voltmeter readings using energy hills

So, the voltmeter is connected across the circuit component (battery or bulb) in order to measure the energy shifted for each coulomb of charge passing through the component. It measures the energy shifted each time one unit of charge passes through the component.

Making sense of voltmeter readings with series connections using energy hills

As before, we assume that no energy is shifted to the surroundings through the connecting wires.

So, the sum of the energies shifted by each bulb is equal to the energy shifted from the chemical store of the battery. So we have X + X is equal to 3.0 volt. So X is 1.5 volt, assuming the bulbs have equal resistances.

Making sense of voltmeter readings with parallel connections using energy hills

As before, we assume that no energy is shifted to the surroundings through the connecting wires.

So, the full battery voltage of 3 volt is dropped across each bulb. Once again, we suggest you keep the description simple, and assume that no energy is shifted to the surroundings by the connecting wires.