Brown was studying pollen grains of the plant Clarkia pulchella suspended in water under a microscope when he observed minute particles, ejected by the pollen grains, executing a jittery motion.

All observed elementary particles are either fermions or bosons.

It consisted of several detector types for observing secondary particles from particle cascades in the atmosphere.

The ultramicroscope system can also be used to observe tiny nontransparent particles dispersed in a transparent solid or gel.

Concentration must be sufficiently low for observing individual particles.

Among many other activities, they can look through telescopes, inspect meteorites, observe subatomic particles in a cloud chamber and spin a globe to see atmospheric turbulence.

If this process continues, we will observe larger particles called mychits, or bacteria-nuclei forming the basis of a bacterium.

Observing photons, particles, and gravitational waves enables researchers to probe astrophysical objects and processes.

"You used a shovel," he remarked, observing a sprinkling of small gravel, tiny brown bits of bark, and particles of splintered wood as fine as needles.

No one had observed such particles.