6. A student adds a mixture of oil, sand and salt in a beaker of water and stirs it. The student stops stirring, and observes that the salt is no longer visible. It is also observed that the oil floats on the top and the sand sinks to the bottom of the beaker.
a. Why does oil float on water?
b. Why is salt no longer visible after the stirring?
c. How can you separate the components of this mixture?​