Nanotechnology refers to controlling and manipulating matter at the atomic and molecular scale, generally 100 nanometers or smaller. It has the potential to create new materials and devices with applications in medicine, electronics, and energy. While the concept was first introduced in 1959, scientific research has expanded greatly in recent decades. There are two main approaches - building from the bottom up using molecular components, or constructing from larger entities without atomic control. Many existing products already use nanotechnology, including sunscreens, self-cleaning glass, clothing, and swimming pool cleaners. Nanowires and carbon nanotubes show particular promise for electronics and other applications due to their extraordinary properties compared to existing materials.