1. A small container and a big glass.
5. Glue and coin.
6. A spoon.
If the container is made of plastic, we stick a coin at its base in order to get more stability and avoid floating.
We fill the half a container with oil.
We put it at the bottom of the glass.
We pour the alcohol necessary to cover the container very carefully.
Then, we add water little by little with a spoon (it must slip from the wall of the glass).
Small container's surface filled with oil will adopt a convex shape until the water you add is enough. Then, the oil will separate from this container and it will have a spherical form that will remain just in the middle inside the oil and water mixture.
First, we must know the densities of the liquids we use in the experiment.
- water (1g/ml)
- oil (0'92 g/ml)
- Alcohol (0'75 g/ml)
The oil floats in the water because it's less dense than water, but it sinks into alcohol because it's denser than it. In conclusion, you can prepare a mixture with alcohol and water because inside it, oil won’t float or sink.
by Ana, Marta and Belén