Potential energy is also known as energy at rest or stored energy. Common types of potential energy include the gravitational potential energy stored in an apple hanging from a tree, the electrical potential energy stored in an object due to the attraction or repulsion of electric charges, and the chemical potential energy stored in the bonds between atoms and molecules. Additionally, the nuclear energy stored in an atomic nucleus and the elastic energy stored in a stretched spring due to its configuration are also types of potential energy.
Usually, objects or systems with high potential energy tend to be less stable, and thus move toward lower energy levels to attain stability. For instance, the radioactive element Uranium-235 (235U) has an unstable nucleus. To gain stability, it splits into smaller but more stable elements, and releases the stored nuclear energy. This released energy can then be used to generate electricity in nuclear power plants.