Lanterns

A lantern is a portable lighting device used to illuminate broad areas. Lanterns may also be used for signaling, to guide your path somewhere or as general light sources for camping. In the older days it would have been used like a torch. Dim varieties are often used for decoration. The term "lantern" is also used more generically to mean a 'light source' or the enclosure for a light source, i.e., the housing for the lamp and lens — that is the top section — of a lighthouse.

Some lanterns are battery-powered and have a simple lightbulb, but power supply to operate a Fluorescent lamp. They are easy to use and comparatively durable, but less bright than propane or liquid fuel lanterns, require battery replacement, or if rechargeable and not constantly plugged in must be brought to full charge every few months.
Some rechargeable fluorescent lanterns may be plugged in at all times and may be set up to illuminate upon a power failure, a useful feature in some applications. During extensive power failures , supplemental recharging may be provided from an automobile's twelve volt electrical system or from a modest solar powered charger. Solar-powered lanterns have become popular in developing countries where they provide a safer and cheaper alternative to kerosene lamps.
Battery-powered lanterns utilizing LEDs are becoming increasingly popular due to improvements in LED technology and reduced production costs. LEDs have become brighter and more rugged, and typically run longer than incandescent bulbs or fluorescent tubes of comparable brightness.

The uses of horses

Horses are trained and ridden for practical working purposes such as in police work or for controlling herd animals on a ranch. They are also used in competitive sports including, but not limited to, dressage, endurance riding, eventing, reining, show jumping, tent pegging, vaulting, polo, horse racing, driving, and rodeo. Some popular forms of competit

ion are grouped together at horse shows, where horses perform in a wide variety of disciplines. Horses (and other equids such as mules and donkeys) are used for non-competitive recreational riding such as fox hunting, trail riding or hacking. There is public access to horse trails in almost every part of the world; many parks, ranches, and public stables offer both guided and independent riding. Horses are also used for therapeutic purposes, both in specialized paraequestrian competition as well as non-competitive riding to improve human health and emotional development.
Horses are also driven in harness racing, at horse shows and in other types of exhibition, historical reenactment or ceremony, often pulling carriages. In some parts of the world, they are still used for practical purposes such as farming.
Horses continue to be used in public service: in traditional ceremonies (parades, funerals), police and volunteer mounted patrols, and for mounted search and rescue.

Diethyl ether (Ethoxy ethane)

Diethyl ether, also known as ether, is the organic compound with the formula (CH3-CH2)2O. It is a colorless and highly flammable liquid with a low boiling point and a characteristic odor. It is the most common member of a class of chemical compounds known generically as ethers. It is a common solvent and was once used as a general anesthetic. Ether is sparingly soluble in water (6.9 g/100 mL).

Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95% .
Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a strong acid, typically sulfuric acid, H2SO4. The acid dissociates producing hydrogen ions, H+. A hydrogen ion protonates the electronegative oxygen atom of the ethanol, giving the ethanol molecule a positive charge:
CH3CH2OH + H → CH3CH2OH2 A nucleophilic oxygen atom of unprotonated ethanol displaces a water molecule from the protonated (electrophilic) ethanol molecule, producing water, a hydrogen ion and diethyl ether.
CH3CH2OH2+ + CH3CH2OH → H2O + H+ + CH3CH2OCH2CH3
This reaction must be carried out at temperatures lower than 150 °C in order to ensure that an elimination product (ethylene) is not product of the reaction. At higher temperatures, ethanol will dehydrate to form ethylene. The reaction to make diethyl ether is reversible, so eventually an equilibrium between reactants and products is achieved. Getting a good yield of ether requires that ether be distilled out of the reaction mixture before it reverts to ethanol, taking advantage of Le Chatelier's principle.
Another reaction that can be used for the preparation of ethers is the Williamson ether synthesis, in which an alkoxide (produced by dissolving an alkali metal in the alcohol to be used) performs a nucleophilic substitution upon an alkyl halide.

Photo electric effect

In another paper published in that same year, Albert Einstein undermined the very foundations of classical electromagnetism. His theory of the photoelectric effect (for which he won the Nobel prize for physics) posited that light could exist in discrete particle-like quantities, which later came to be known as photons. Einstein's theory of the photoelectric effect extended the insights that appeared in the solution of the ultraviolet catastrophe presented by Max Planck in 1900. In his work, Planck showed that hot objects emit electromagnetic radiation in discrete packets, which leads to a finite total energy emitted as black body radiation. Both of these results were in direct contradiction with the classical view of light as a continuous wave, although it is now known that the photoelectric effect does not, in fact, compel one to any conclusion about light being made of "photons", as discussed in the photoelectric effect article.[citation needed] Planck's and Einstein's theories were progenitors of quantum mechanics, which, when formulated in 1925, necessitated the invention of a quantum theory of electromagnetism. This theory, completed in the 1940s, is known as quantum electrodynamics (or "QED"), and, in situations where perturbation theory is applicable, is one of the most accurate theories known to physics.

Ozone layer

The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 93–99% of the sun's high frequency ultraviolet light, which is potentially damaging to life on earth. Over 91% of the ozone in Earth's atmosphere is present here. It is mainly located in the lower portion of the stratosphere from approximately 10 km to 50 km above Earth, though the thickness varies seasonally and geographically. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations which continues to operate today. The "Dobson unit", a convenient measure of the columnar density of ozone overhead, is named in his honor.

Earthquake

An Earthquake is a sudden shake of the Earth's crust.The vibrations may vary in magnitude. The underground point of origin of the earthquake is called the "focus". The point directly above the focus on the surface is called the"epicentre". Earthquakes by themselves rarely kill people or wildlife. It is usually the secondary events that they trigger, such as building collapse, fires, tsunamis (seismic sea waves) and volcanoes, that are actually the human disaster. As many of these could be avoided by better construction, safety systems, early warning and evacuation planning, the term unnatural disaster is not unwarranted.
Earthquakes are caused by the discharge of accumulated along geologic faults.

Rainbow

A rainbow is an optical and meteorological phenomenon that causes a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth's atmosphere. They take the form of a multicoloured arc, with red on the outer part of the arch and violet on the inner section of the arch.
A rainbow spans a continuous spectrum of colours; the discrete bands are an artefact of human colour vision. The most commonly cited and remembered sequence, in English, is Newton's sevenfold red, orange, yellow, green, blue, indigo and violet (popularly memorized by mnemonics like Roy G. Biv). Rainbows can be caused by other forms of water than rain, including mist, spray, and dew.