Edmond Halley FRS (8 November 1656 – 14 January 1742) was an English astronomer, the second Astronomer Royal.
He was also a mathematician, meteorologist, and physicist. Halley is best known for computing the orbit of the comet named after him: Halley's Comet.
On leaving Oxford, in 1676, Halley visited the south Atlantic island of St. Helena and set up an observatory with a telescope which had no tube.
He used the telescope to study stars from the Southern Hemisphere. He later published "Catalogus Stellarum Australium" which was about the 341 southern stars.
In 1686, Halley published the second part of the results from his St. Helena expedition. This was a paper and chart on trade winds and monsoons. He thought solar heating caused atmospheric motions. He also established the relationship between barometric pressure and height above sea level. His charts were an advance in how to display information visually. Halley also persuaded Sir Isaac Newton to publish a book about his discovery of gravity.
In 1690, Halley built a diving bell, a device in which the atmosphere was replenished by way of weighted barrels of air sent down from the surface. In a demonstration, Halley and five companions dived to 60 feet in the River Thames, and remained there for over an hour and a half. Halley's bell was of little use for practical salvage work, as it was very heavy, but he made improvements to it over time, later extending his underwater exposure time to over 4 hours.
That same year, at a meeting of the Royal Society, Halley introduced a rudimentary working model of a magnetic compass using a liquid-filled housing to damp the swing and wobble of the magnetized needle.
In 1691 Halley sought the post of Savilian Professor of Astronomy at Oxford University. As he was well known as an atheist, he was opposed by the Archbishop of Canterbury, John Tillotson. The post went instead to a mathematician who had the support of Isaac Newton.
In 1693 Halley published an article on life annuities (a kind of pension), which featured an analysis of age-at-death on the basis of the Breslau statistics Caspar Neumann had been able to provide. This article allowed the British government to sell life annuities at an appropriate price based on the age of the purchaser. Halley's work strongly influenced the development of actuarial science. The construction of the life-table for Breslau, which followed more primitive work by John Graunt, is now seen as a major event in the history of demography.
These are generally either , rhyming with "valley", or ""Hailey"," though some people will use Halley's supposed pronunciation of his own name, ""Hawley"." The ""Hailey"" pronunciation inspired the rock and roll singer Bill Haley to call the rest of his band his "Comets" after Halley's Comet.
Collective names of groups of like elements
There are areas on the periodic table where elements have similar properties. For example, all of the first column elements (alkali metals) are light, very soft, react with water rapidly, make hydroxides that are strong bases, and react with the halogens to make colorless ionic compounds.
The second column elements (alkaline earth metals) are a little heavier, a little harder, react with water a little less rapidly, made hydroxides that are strong bases, and react with the halogens to make colorless ionic compounds.
The other categories are: transition metals, pnictogens, chalcogens, halogens, and noble gases. There are also inner transition metals that are divided into lanthanides and actinides.
Flamsteed designation
Flamsteed designations are for stars that are similar to Bayer designations. However, they use numbers instead of Greek letters. Flamsteed designation contained 2554 stars.
The numbers are usually assigned in the order of increasing right ascension within each constellation. However, because of the effects of precession, they are now slightly out of order in some parts. This method first appeared in John Flamsteed's "Historia Coelestis Britannica", a book that was published by Edmond Halley and Isaac Newton together in 1712.
Inner transition metal
Inner transition metals (ITM) are chemical elements on the periodic table. They are normally shown in two rows below all the other elements. They include elements 57-71, or lanthanides, and 89-103, or actinides. The lanthanides are very similar, and the actinides are all radioactive.
ITMs have three incomplete outermost electron shells and are all metals. In some cases they are quite malleable and ductile. Many lanthanides such as Lutetium are used in the lighting industry. Actinides don't occur in nature (except for thorium and uranium), and are highly unstable.
These elements belong to f-block and are known as the anti-penultimate shell.
Its general configuration is (n-2)f^0-14(n-1)d^0-2np^6ns^2 where n= 6-7.
Molar mass
Molar mass is the mass of a substance that has 6.022 × 10 atoms (Avogadro's number). The mass number of an element is equal to the molar mass of the element . The molar mass of a chemical compound is the mass when the compound has 6.022 × 10 molecules. Molar mass of Chlorine is 35.45 due to consideration of avg molar mass by including mass of its all isotopes.
It can be found by adding the molar masses of all of its elements. Sodium hydroxide's (NaOH) molar mass can be found by adding the molar mass of sodium, oxygen, and hydrogen, which would be 39.997 g/mo
Absolute hot
Absolute hot is the hottest temperature that matter can reach. It is measured at 1.41678571 × 10 kelvins. It is the opposite of Absolute zero which is -273.15°C on the Celsius scale or 0 K on the Kelvin scale. When something reaches this temperature, normal physics completely changes.
D-block
The D-block is a group of elements on the periodic table. They include the transition metals. The Group 12 elements are normally called post-transition metals because they are different from the transition metals. The Group 12 elements are still in the d-block though. The d-block can hold up to ten (10) electrons at most.
Group 12 element
A group 12 element is a group in the periodic table of chemical elements. It includes zinc, cadmium, mercury, and copernicium. Copernicium is not stable so its properties are not clear. They all have low melting and boiling points. Mercury is even a liquid. Zinc is the least electronegative and most reactive of the Group 12 elements.
Period 4 element
A period 4 element is an element in the fourth period (row) of the periodic table. It begins at potassium and ends at krypton. Period 4 has 18 elements.
Period 4 elements have electrons in the first four electron shells. All period 4 elements have one or more electrons in the fourth electron shell (valence electrons). When atomic number increases by one, another electron is added. Two electrons join the 4s orbital, ten electrons join the 3d orbital, and and six electrons join the 4p orbitals.
Kilogram per cubic metre
A kilogram per cubic meter is a measurement of density. It is defined as the amount of kilograms that one cubic meter of a substance has in it.
Smokey Harris
Wilfred Smokey Harris (born October 11, 1890 in Port Arthur, Ontario, Canada - June 4, 1974) was a Canadian professional ice hockey forward.
Harris began playing professional ice hockey with the Vancouver Millionaires in 1911. After spending some time with the Millionaires he moved on to play for the Seattle Metropolitans and Portland Rosebuds. Eventually he would find his way to the other side of the country to play for the Boston Bruins in the National Hockey League where he scored the first goal in the teams history.
Kilojoule per mole
A kilojoule per mole is a way of measuring the amount of heat needed for something. It is the number of kilojoules needed to make the reaction in one mole of substance.
Enthalpy of fusion