Nanotechnology involves manipulating matter at the atomic or molecular scale. A nanometer is one billionth of a meter. Key tools for nanotechnology include scanning probes like atomic force microscopes and scanning tunneling microscopes. Applications include carbon nanotubes in electronics, fabrics that are water or stain resistant, and flexible displays using nanowires. Nanotechnology may enable lighter, stronger materials and advance fields like energy, medicine, and space exploration, but risks include health impacts of nano-particles and potential military uses.