Dissolves cooking oil in water

Experiment: The journey of the paint drop

What is happening:

Oil and water do not mix. The oil floats on the water. The drop of food coloring sinks down in the oil layer and does not mix with the oil either. It stays on the boundary between water and oil for a while until it breaks through. Then the food coloring mixes with the water and colors the water.


Oil has a lower density than water, i.e. 100ml oil weighs less than 100ml water. That is why the oil floats on the water. In addition, these two liquid kites cannot be mixed, because basically only the same can be mixed with the same. The smallest particles (molecules) of water and oil look different. Food coloring (water-based) consists mainly of water, which logically means that it mixes with water but not with oil.

If you now drip the paint into the oil, it tries to differentiate itself from the oil. The water (the water-based food coloring) minimizes its surface area so that it has as few points of contact with the oil as possible. The smallest surface area, compared to its volume, has the shape of a sphere. Therefore, as long as the drop of food coloring remains in the oil, it will form a ball. If it breaks through (due to its weight - see above: water, also food coloring, has a greater density than oil), the opposite happens, the ball dissolves and the food coloring is distributed in the water.