Problem
Alice recently read a popular magazine description of quantum physics. The article describes how quantum measurements always alter the state of the system being measured. The author of the article explains that the reason for this happening is that quantum systems are always very small and hence fragile, and hence any interaction with them, in order to measure them, disturbs them. As an example, the author explains that in order to "see" and electron, it is necessary to interact with it with another particle, and that interaction will change the state of the electron.