Repulsion is a strong feeling of disgust or the force that pushes things apart.

When you feel repulsion toward something, you want to get away from it immediately and powerfully. You might feel repulsion at the sight of moldy food or the smell of garbage on a hot day. Your body and mind react with a powerful “get me away from this” feeling. Scientists believe we evolved this response to protect us from things that might make us sick.

In science, repulsion describes forces that push objects apart. When you try to press the north poles of two magnets together, you feel magnetic repulsion pushing them apart. The magnets want to flip around so opposite poles can attract. Similarly, when you rub a balloon on your hair, electrical repulsion between the hairs makes them stand up and spread apart.

The opposite of repulsion is attraction: magnets attract when opposite poles meet, and we feel attracted to things we find pleasant or interesting. Understanding both forces helps explain everything from how magnets work to why oil and water don't mix (water molecules have a kind of repulsion toward oil molecules).