The phonograph, record player, or gramophone (from the Greek: gramma = "letter" and phōnē = "voice").
The phonograph was invented in 21 November 1877 by Thomas Edison. While other inventors had produced devices that could record sounds, Edison's phonograph was the first to be able to reproduce the recorded sound. His phonograph originally recorded sound onto a tinfoil sheet phonograph cylinder, and could both record and reproduce sounds. The recordings played on such a device consist of waveforms that are engraved onto a rotating cylinder or disc. As the cylinder or disc rotates, a stylus or needle traces the waveforms and vibrates to reproduce the recorded sound waves.
E = mc2
A fuss for centuries ?
Albert Einstein did not formulate exactly the formula E = mc2 in his 1905 Annus Mirabilis paper "Does the Inertia of an object Depend Upon Its Energy Content?"; rather, the paper states that if a body gives off the energy L in the form of radiation, its mass diminishes by L/c2. (Here, "radiation" means electromagnetic radiation, or light, and mass means the ordinary Newtonian mass of a slow-moving object). His publication of the journal "Annalen der Physik" reveals the relationship between energy and mass.
Are not the gross bodies and light convertible into one another, and may not bodies receive much of their activity from the particles of light which enter their composition?
In 1734, Emanuel Swedenborg in his Principia theorized that all matter is ultimately composed of dimensionless points of "pure and total motion." He described this motion as being without force, direction or speed, but having the potential for force, direction and speed everywhere within it. There were many attempts in the 19th and the beginning of the 20th century—like those of J. J. Thomson (1881), Oliver Heaviside (1888), and George Frederick Charles Searle (1897), Wilhelm Wien (1900), Max Abraham (1902), Hendrik Antoon Lorentz (1904) — to understand as to how the mass of a charged object depends on the electrostatic field. This concept was called electromagnetic mass, and was considered as being dependent on velocity and direction as well. Another way of deriving some sort of electromagnetic mass was based on the concept of radiation pressure. In1900, Henri Poincaré associated electromagnetic radiation energy with a "fictitious fluid" having momentum and mass.
The Australian Open Tennis
The Australian Open was first played in 1905 as The Australian Championships. The first match was played on 21 November 1905. Because of its geographic remoteness, historically, the event did not gain attendance from the top tennis players. As late as the 1980s, the event lacked participation from top ranked tennis professionals. Since its move to Melbourne Park in 1988, the Australian Open has gained the popularity of the other three Grand Slams.
The woman Grandmaster of India
Eesha Karavade (born 21 November 1987) is a chess player from Pune, India. She holds the title of Woman Grandmaster and International Master. Hercurrent Elo rating is 2365. She plays for India in Chess Olympiad.
Eesha was first runner-up in the 38th National Women's Premier Chess Championship at Chennai.
Jadu Nath Singh: The less remembered bravado
Naik Jadu Nath Singh was a soldier of Indian Army who fought the Indo-Pakistani War of 1947 in Jammu & Kashmir. He died in the battle and was later awarded with the Param Vir Chakra for his bravery in the War. He was the fourth recipient of Param Vir Chakra. Naik Jadu Nath Singh, a Rathore Rajput (21 November 1916
SOME INTERESTING POSTS!!!!!
This inventor of a system for gaining solar power from sea by large floating algea fields producing biofuel is also a violinist
This gibraltar engineer handled the flood water, irrigation systems & patented automatic weir water floodgates!!!