Due to differences in physical properties, oil does not readily mix with water.

This is the source of the saying "oil and water don't mix."

They can't be used with water, since, as you might remember from high school chemistry class, oil and water do not mix.

But preliminary examination suggests the oil did not mix far down into the water.

"In fifth grade, we all learned that oil and water don't mix," she said.

The attempt to do so only gives a brown mud with which the oil will not mix.

In the Middle East, oil and democracy do not mix.

Of course, this is not the first time that oil and politics have mixed.

This is why oil and vinegar (water) do not mix!

You're trying to see if oil and water really do mix?