Dust is made of fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind, volcanic eruptions, and pollution. Dust in homes is composed of about 20–50% dead skin cells. The rest, and in offices and other built environments, is composed of small amounts of plant pollen, human hairs, animal fur, textile fibers, paper fibers, minerals from outdoor soil, burnt meteorite particles, and many other materials which may be found in the local environment.
A dust storm blankets Texas houses, April 1935
Three years of use without cleaning has caused this laptop heat sink to become clogged with dust, and it can no longer be used as it may catch fire.
Domestic dust on a finger
Large dust storm over Libya
In the physical sciences, a particle is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion.
Arc welders need to protect themselves from welding sparks, which are heated metal particles that fly off the welding surface.
Galaxies are so large that stars can be considered particles relative to them