Lycopodium powder is a yellow-tan dust-like powder, consisting of the dry spores of clubmoss plants, or various fern relatives. When it is mixed with air, the spores are highly flammable and are used to create dust explosions as theatrical special effects. The powder was traditionally used in physics experiments to demonstrate phenomena such as Brownian motion.
The powder consists of the dry spores of clubmoss plants, or various fern relatives principally in the genera Lycopodium and Diphasiastrum . The preferred source species are Lycopodium clavatum (stag's horn clubmoss) and Diphasiastrum digitatum (common groundcedar), because these widespread and often locally abundant species are both prolific in their spore production and easy to collect.[ citation needed ]
Today, the principal use of the powder is to create flashes or flames that are large and impressive but relatively easy to manage safely in magic acts and for cinema and theatrical special effects. [1] Historically it was also used as a photographic flash powder. [2] Both these uses rely on the same principle as a dust explosion, as the spores have a large surface area per unit of volume (a single spore's diameter is about 33 micrometers (μm)), [3] and a high fat content.
It is also used in fireworks and explosives, fingerprint powders, as a covering for pills, and as an ice cream stabilizer.
Lycopodium powder is also sometimes used as a lubricating dust on skin-contacting latex (natural rubber) goods, such as condoms and medical gloves. [4]
In physics experiments and demonstrations, lycopodium powder can be used to make sound waves in air visible for observation and measurement, and to make a pattern of electrostatic charge visible. The powder is also highly hydrophobic; if the surface of a cup of water is coated with lycopodium powder, a finger or other object inserted straight into the cup will come out dusted with the powder but remain completely dry.
Because of the very small size of its particles, lycopodium powder can be used to demonstrate Brownian motion. A microscope slide, with or without a well, is prepared with a droplet of water, and a fine dusting of lycopodium powder is applied. Then, a cover-glass can be placed over the water and spore sample in order to reduce convection in the water by evaporation. Under several hundred diameters magnification, one will see in the microscope, when well focused upon individual lycopodium particles, that the spore particles "dance" randomly. This is in response to asymmetric collisional forces applied to the macroscopic (but still quite small) powder particle by microscopic water molecules in random thermal motion. [5]
As a then-common laboratory supply, lycopodium powder was often used by inventors developing experimental prototypes. For example, Nicéphore Niépce used lycopodium powder in the fuel for one of the first internal combustion engines, the Pyréolophore, in about 1807, [6] and Chester Carlson used lycopodium powder in 1938 in his early experiments to demonstrate xerography. [7]
Brownian motion is the random motion of particles suspended in a medium.
Joseph Nicéphore Niépce was a French inventor and one of the earliest pioneers of photography. Niépce developed heliography, a technique he used to create the world's oldest surviving products of a photographic process. In the mid-1820s, he used a primitive camera to produce the oldest surviving photograph of a real-world scene. Among Niépce's other inventions was the Pyréolophore, one of the world's first internal combustion engines, which he conceived, created, and developed with his older brother Claude Niépce.
The Lycopodiaceae are an old family of vascular plants, including all of the core clubmosses and firmosses, comprising 16 accepted genera and about 400 known species. This family originated about 380 million years ago in the early Devonian, though the diversity within the family has been much more recent. "Wolf foot" is another common name for this family due to the resemblance of either the roots or branch tips to a wolf's paw.
An ultramicroscope is a microscope with a system that lights the object in a way that allows viewing of tiny particles via light scattering, and not light reflection or absorption. When the diameter of a particle is below or near the wavelength of visible light, the particle cannot be seen in a light microscope with the usual methods of illumination. The ultra- in ultramicroscope refers to the ability to see objects whose diameter is shorter than the wavelength of visible light, on the model of the ultra- in ultraviolet.
Brownian motors are nanoscale or molecular machines that use chemical reactions to generate directed motion in space. The theory behind Brownian motors relies on the phenomenon of Brownian motion, random motion of particles suspended in a fluid resulting from their collision with the fast-moving molecules in the fluid.
In physics, backscatter is the reflection of waves, particles, or signals back to the direction from which they came. It is usually a diffuse reflection due to scattering, as opposed to specular reflection as from a mirror, although specular backscattering can occur at normal incidence with a surface. Backscattering has important applications in astronomy, photography, and medical ultrasonography. The opposite effect is forward scatter, e.g. when a translucent material like a cloud diffuses sunlight, giving soft light.
Lycopodium is a genus of clubmosses, also known as ground pines or creeping cedars, in the family Lycopodiaceae. Two very different circumscriptions of the genus are in use. In the Pteridophyte Phylogeny Group classification of 2016, Lycopodium is one of nine genera in the subfamily Lycopodioideae, and has from nine to 15 species. In other classifications, the genus is equivalent to the whole of the subfamily, since it includes all of the other genera. More than 40 species are accepted.
Flash powder is a pyrotechnic composition, a mixture of oxidizer and metallic fuel, which burns quickly (deflagrates) and produces a loud noise regardless of confinement. It is widely used in theatrical pyrotechnics and fireworks and was once used for flashes in photography.
Lycopodium clavatum is the most widespread species in the genus Lycopodium in the clubmoss family.
Diphasiastrum is a genus of clubmosses in the plant family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016, it is placed in the subfamily Lycopodioideae. It is closely related to the genus Lycopodium, and some botanists treat it within a broad view of that genus as a section, Lycopodium sect. Complanata. Some species superficially resemble diminutive gymnosperms and have been given common names such as ground-pine or ground-cedar.
"Über die von der molekularkinetischen Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten suspendierten Teilchen" is the 1905 journal article, by Albert Einstein, that proved the reality of atoms, the modern understanding of which had been proposed in 1808 by John Dalton. It is one of the four groundbreaking papers Einstein published in 1905, in Annalen der Physik, in his miracle year.
Spinulum annotinum, synonym Lycopodium annotinum, known as interrupted club-moss, or stiff clubmoss, is a species of clubmoss native to forests of the colder parts of North America, as well as Asia, and most of Europe. It is an evergreen perennial pteridophyte. The genus Spinulum is accepted in the Pteridophyte Phylogeny Group classification of 2016, but not in other classifications, which submerge the genus in Lycopodium.
Diphasiastrum digitatum is known as groundcedar, running cedar or crowsfoot, along with other members of its genus, but the common name fan clubmoss can be used to refer to it specifically. It is the most common species of Diphasiastrum in North America. It is a type of plant known as a clubmoss, which is within one of the three main divisions of living vascular plants. It was formerly included in the superspecies Diphasiastrum complanatum. For many years, this species was known as Lycopodium flabelliforme or Lycopodium digitatum.
The Pyréolophore was an early internal combustion engine and the first made to power a boat. It was invented in the early 19th century in Chalon-sur-Saône, France, by the Niépce brothers: Nicéphore and Claude. In 1807 the brothers ran a prototype internal combustion engine, and on 20 July 1807 a patent was granted by Napoleon Bonaparte after it had successfully powered a boat upstream on the river Saône.
Claude Félix Abel Niépce was a French inventor and the older brother of the more celebrated Nicéphore Niépce. Claude traveled to England to try to find a sponsor for their internal combustion engine and died there. His brother's later successful development of photography has eclipsed the part played by Claude.
Dendrolycopodium obscurum, synonym Lycopodium obscurum, commonly called rare clubmoss, ground pine, or princess pine, is a North American species of clubmoss in the family Lycopodiaceae. It is a close relative of other species such as D. dendroideum and D. hickeyi, also treelike. It is native to the eastern United States and southeastern Canada from Georgia to Minnesota to Nova Scotia. It grows in the understory of temperate coniferous and deciduous forests, where it is involved in seral secondary succession, growing in clonal colonies some years after disturbance has occurred. It has also been found in Japan, Taiwan, Korea, Russian Far East, and northeastern China.
Diphasiastrum tristachyum, commonly known as blue clubmoss, blue ground-cedar, ground pine, deep-rooted running-pine or ground cedar, is a North American and Eurasian species of clubmoss. In North America, it has been found from Newfoundland west to Manitoba, and south as far as Georgia and Alabama. In Eurasia, it ranges from southern Norway and Sweden south to France and Italy and it also occurs in the Caucasus.
A powder is a dry, bulk solid composed of many very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms powder and granular are sometimes used to distinguish separate classes of material. In particular, powders refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing. Granulars refer to the coarser granular materials that do not tend to form clumps except when wet.
Lycopodiella alopecuroides, the foxtail clubmoss, is a species of perennial vascular plant in the club-moss family, Lycopodiaceae. It is commonly found along the Atlantic seaboard and has been recently been discovered in the state of Maine. The family, Lycopodiaceae contains nearly 15 genera and about 375 species