How the measurement is done depends on the physical implementation of the qubit. For example the state of the qubit could affect the resonance frequency of a co

How the measurement is done depends on the physical implementation of the qubit. For example the state of the qubit could affect the resonance frequency of a coupled microwave cavity which can be measured using RF techniques. Obviously at some point the experimenter has to check the result of the measurement, which makes the question what would have happened without a conscious observer impossible to answer.