Hydrophobic substances are those that repel water. They do this because their molecules are nonpolar, meaning they don't have a positive and negative end like water molecules do. This means they can't form hydrogen bonds with water molecules, which are the bonds that make water cohesive.

Here are some examples of hydrophobic substances:

* Oils and fats: These are made up of long chains of hydrocarbons, which are nonpolar.

* Waxes: These are also made up of long chains of hydrocarbons, but they're more solid than oils and fats.

* Plastic: Many plastics are hydrophobic because they're made from long chains of nonpolar molecules.

* Some fabrics: Some fabrics, like polyester and nylon, are hydrophobic because they're made from synthetic fibers that don't absorb water.

The opposite of hydrophobic is hydrophilic, which means "water-loving." Hydrophilic substances attract water because their molecules are polar and can form hydrogen bonds with water molecules.