OIL POMP

Materials:
1 One small container and one larger glass
2 Oil
3 Water
4 Glue and one coin
5 Spoon
6 Alcohol

Assembly:
1. If the container is of plastic we put on the base one coin to give it stability and to avoid that it floats.
2. You take the small container, and you fill the container until the middle with oil and you see that the oil sets on the bottom of the glass.
3 Inside the glass you fill with precaution, the amount of alcohol that you need to cover the small container. Then with a spoon, you add, little by little, water.The surface of the oil from the small container will be more and more convex, when the water that you have added is the necessary, the oil will give off the container and will forma sphere that will be floating inside the mixture of water and alcohol.

Explanation:
The densities of the three liquids : water (1g/ml), oil (0,92g/ml) and alcohol (0,79g/ml).
The oil floats on the water because it is less dense than the water, but the oil doesn’t float on the alcohol because it is denser. So you can prepare one mixture of water an alcohol, where this oil won’t float and won’t sink until the bottom.

by Macarena, Irene and Sofía