Final answer:
A One-way mirror is commonly used in social science research, particularly in psychology and sociology, to conduct experiments and observations. It is popular for studying group behavior in research labs, such as product usage studies with children.
Step-by-step explanation:
A One-way mirror is commonly used in social science research, specifically in psychology and sociology. It is popular for conducting experiments and observations in research labs, particularly for studying group behavior. For example, a one-way mirror can be used in a product usage study where children are observed playing in a Fisher-Price lab. The mirror allows researchers to observe the children's behavior without them being aware that they are being observed.