Because of the existence of gravity on the earth, oil is lighter than water, so it will float on water. The two of them cannot be blended together. And this problem.
It can be solved perfectly in the space station. Because the space station has no gravity and is a weightless environment, there is no question of who is heavier, they can.
Very well blended together. So what is the use of blending two things that cannot be blended together? This is very, very useful. Because of the materials we can come into contact with in our lives.
Most of them are of this kind of composite material, rarely a single material. For example, the iron we often use is not pure iron, but an alloy of iron and carbon.
We call this kind of thing steel, and mixing different materials together will show some special characteristics. And some features can be used by us.
But on the earth, because of the existence of gravity and the problem of specific gravity, not all materials can be combined together. This problem does not exist in the space station.