Science Buddies: "Ask an Expert"

My child is in year 7 and is currently doing an assignment on separation techniques for chemistry.

He was asked if you have a mixture on iron, salt, sand, polystyrene and oil, how would you separate them and in what order. This is his order so far..

Iron - remove with a magnet
Polystyrene - floats so when water is added, scoop it off the top of the water.
Sand - filtration, pour through filter paper etc
Salt - evaporation, heat the dish so water evaporates and leaves salt crystals.

He is stuck on is the oil separation. He knows oil floats in water, so could it simply be scooped off the surface of the water? If he uses the filtration method, he is sure that the oil and sand would then be together and is not sure how the separate oil and sand.

I'm not much of a Science person myself, it was not my best subject at school but I am having trouble pointing him in the right direction and finding a solution on the internet. Can anyone offer any advice please?

Thanks in advance.

Hi CAZ1978,
It sounds like your child is on the right track approaching this!

For the oil separation, please take a look at these Oil Water Separators. http://www.hydroflotech.com/products/oi ... separators The oil is "skimmed" using the skimmer at the top of the OWS. This type of design are used quite frequently in the industry, especially in wastewater application.

Please let us know if there's anything else we can do to help!
Willey