In a mixture of water and lubricating oil at 70°F, which would settle first in a container?

In a mixture of water and lubricating oil, at 70°F, the lubricating oil would settle on top of the water. This phenomenon occurs due to the differences in density between the two fluids.

Water has a higher density compared to most oils, which is why oil typically floats atop water when mixed. The density of water is about 1 g/cm³, while the density of many lubricating oils usually ranges from 0.8 to 0.9 g/cm³. As a result, when these two liquids are combined, the less dense lubricating oil will rise and settle above the denser water.

If equal amounts of oil and water are mixed, the oil will still float on top because of this density difference, further supporting the idea that oil would settle above water in a container. Therefore, regardless of the quantities mixed, the oil, being less dense, will always rise to the surface and settle there.