Disinterested vs. Uninterested

Disinterested
Means impartial ,having no personal involvement in a particular situation or receiving no advantage and therefore free to act in a fair and unselfish way.

- The scientists ,of course,is expected to be impartial and disinterested.
- My advice is completely disinterested.
- France's intervention in the dispute was not entirely disinterested.It gave her increased power and influence in the area.

Uninterested
Having no interest or feelings about someone/something .

- Only 22% percent of the population voted.The rest were totally uninterested.
- He is completely uninterested in anything to do with politics.
- Kids today are completely uninterested in schoolwork.

Notice that disinterested can also mean uninterested and this use has come to be widely used by many educated writers today ,though some regard it as incorrect.