Then you are just lying to the 8 year old. Sure you can adapt how much context you give based on who's asking, but if it's something factual like this it reall

Then you are just lying to the 8 year old. Sure you can adapt how much context you give based on who's asking, but if it's something factual like this it really shouldn't change from a yes to a no. If you think they _meant_ to ask a different question that is less vague, it can be clarified "Water and oil do not mix by hand. However water and oil can mix under some specific conditions like a vacuum, do you want to discuss that in more detail?"