The Mislabeled Bottles

Three bottles stand on a shelf: milk, water, and juice. Each label, however, is incorrect! You can only take one sip from one bottle. Can you determine the true contents of each bottle with just this single sip?

Solution: Sip from the bottle labeled "juice." If it tastes like milk, then the other two labels are also swapped (milk is water and water is juice). If it tastes like water, then the "water" label is correct, and the "milk" label belongs to the juice bottle.