Conservapedia - User contributions [en]

Antimatter

2008-02-22T23:17:54Z

Sepura: typo

[[Matter]], and therefore everything seen, is made out of 3 different types of substances that [[physicist]]s call particles: [[electron]]s, [[proton]]s and [[neutron]]s.

These particles have been mysterious for quite some time: although [[physicist]]s knew they existed, they knew very little about them. In [[physics]], you can say you "know" something when, among other proprieties, you can predict and describe the way it behaves. You know that a [[stone]] will fall if it's not held properly. [[Physicist]]s can describe how it falls and predict exactly where it will touch the [[ground]] using mathematical formulas.

But physicists couldn't predict anything about the electron! Until a [[Paul Dirac]] thought about it: he found a very simple way to describe the proprieties and behavior of electrons, but... there was something curious about it. His description would only work if the electron had a "[[twin]]" particle, identical to it but with an opposite electric charge. It would be just like its mirror image!
He called it an [[antielectron]] or [[POSITRON]]. Of course, the same would be true for any existing particle ([[proton]] and [[antiproton]], [[neutron]] and [[antineutron]]).

About 100 [[year]]s ago, a [[physicist]] named [[Albert Einstein]] discovered something very important: he said that matter is a very concentrated form of [[energy]]. So if energy and matter are the same thing, you can create matter with energy and you can create energy with matter.

Of course, to make matter a lot of it is needed, and very much concentrated in space. Particles and antiparticles are always created together, out of energy.

The first success was the creation of an "electron-positron" pair, twins that only require a relatively small amount of energy-dough to make them. Later came pairs of protons and antiprotons, then pairs of neutrons and antineutrons.

Antiparticles created in a laboratory "live" for a very short time before they crash into normal particles and annihilate. But nevertheless, they do exist.

Paul Dirac wondered, if protons, electrons and neutrons stick together to make atoms, and atoms stick together to make everything around us, what we call matter, then what about positrons, antiprotons and antineutrons? Do they stick together to make antiatoms? Are antiatoms the building bricks of antimatter? Modern-day physicists agree with him. But thinking something is possible doesn't mean it's necessarily true.

Scientists are hard at work on this mystery at a place called [[CERN]] they are trying to build antimatter. If some of the originally-created antiparticles are still around, they certainly can't be nearby some people think those antiparticles could be somewhere far, far away in the Universe. Some people think the antiparticles do not exist anymore. Something may have happened, just after their [[creation]], which destroyed them all, leaving only particles for the hard task of building up the Universe.

When a particle meets its antiparticle, they destroy each other, releasing a burst of energy such as gamma rays. In 1978, gamma ray detectors flown on balloons detected a type of gamma ray emerging from space that is known to be emitted when electrons collide with positrons — meaning there was antimatter in space.

These gamma rays apparently came from a cloud of antimatter roughly 10,000 light-years across surrounding our galaxy's core. This giant cloud shines brightly with gamma rays, with about the energy of 10,000 suns.

What exactly generated the antimatter was a mystery for the following decades. Suspects have included everything from exploding stars to dark matter.

Now, an international research team looking over four years of data from the European Space Agency's International Gamma Ray Astrophysics Laboratory (INTEGRAL) satellite has pinpointed the apparent culprits. Their new findings suggest these positrons originate mainly from stars getting devoured by black holes and neutron stars.

As a black hole or neutron star destroys a star, tremendous amounts of radiation are released. Just as electrons and positrons emit the tell-tale [[gamma rays]] upon annihilation, so too can gamma rays combine to form electrons and positrons, providing the mechanism for the creation of the antimatter cloud, scientists think.

The researchers calculate that a relatively ordinary star getting torn apart by a black hole or neutron star orbiting around it — a so-called "low mass X-ray binary" — could spew on the order of one hundred thousand billion billion billion billion positrons (a 1 followed by 41 zeroes) per second. These could account for a great deal of the antimatter that scientists have inferred, reducing or potentially eliminating the need for exotic explanations such as ones involving dark matter.

[[Category:Physics]]

Talk:Electron

2008-02-22T23:14:37Z

Sepura: Mass, charge and spin are all wrong?

Why was the information about electrons making up atoms removed? Also, I believe it would be a positive move if the article can be worded in a way that lay people can understand and follow what is being said. [[User:Learn together|Learn together]] 04:12, 2 September 2007 (EDT)
:The information wasn't removed, but the first sentence was kinda wordy and redundant. "Fundamental particle" already implies that they make up atoms, and "fundamental subatomic particle" is more specific. I agree it's a little technical right now, I'll try to work on that in a bit.[[User:Fantasia|Fantasia]] 11:50, 2 September 2007 (EDT)

== Mass, charge and spin are all wrong? ==

According to [http://en.wikipedia.org/wiki/Electron], the electron has mass 9.10938215(45)×10–31 kg, charge –1.602176487(40)×10–19 C, and spin 1/2. [[User:Sepura|Sepura]] 18:14, 22 February 2008 (EST)

Talk:Electron

2008-02-22T23:10:25Z

Sepura:

Why was the information about electrons making up atoms removed? Also, I believe it would be a positive move if the article can be worded in a way that lay people can understand and follow what is being said. [[User:Learn together|Learn together]] 04:12, 2 September 2007 (EDT)
:The information wasn't removed, but the first sentence was kinda wordy and redundant. "Fundamental particle" already implies that they make up atoms, and "fundamental subatomic particle" is more specific. I agree it's a little technical right now, I'll try to work on that in a bit.[[User:Fantasia|Fantasia]] 11:50, 2 September 2007 (EDT)

== Spin 1/3 ? ==

According to [http://en.wikipedia.org/wiki/Electron], the electron is a spin 1/2 particle. [[User:Sepura|Sepura]] 18:10, 22 February 2008 (EST)

Admiral Graf Spee (heavy cruiser)

2008-02-22T21:25:59Z

Sepura: typo

{| border="1" align="right" cellpadding="2" cellspacing="0" width="300" style="margin-left:5px"
|align="center" colspan="2"|[[Image:Graf Spee cruiser.jpg|300px]]
|-
!colspan="2" align="center" style="color: black; height: 30px; background: tan no-repeat scroll top left;"|''Admiral Graf Spee''
|-
!align ="center" style="color: black; height: 30px; background: tan no-repeat scroll top left;"|Career
!align ="center" style="color: black; height: 30px; background: tan no-repeat scroll top left;"|[[Image:Nazi Germany Jack.png|48px|Jack of Nazi Germany]]
|-
|-
| Class:
| ''Deutschland''
|-
| Laid down:
| 1 October 1932
|-
| Launched:
| 30 June 1934
|-
| Commissioned:
| 6 January 1936
|-
| Fate:
| Scuttled by crew
|-
! colspan="2" align="center" style="color: black; height: 30px; background: tan;"| General characteristics
|-
| Displacement:
| 12,100 tons
|-
| Length:
| 610 feet
|-
| Beam:
| 71 feet
|-
| Draft:
| 24 feet
|-
| Speed:
| 28.5 knots
|-
| Complement:
| 1,150 officers and men
|-
|}
'''''Admiral Graf Spee''''' was a warship in the navy of [[Germany]] during [[World War II]], whose success as a surface raider in the South Atlantic led to its loss by scuttling near [[Uruguay]]. She was named for Maximilian Graf von Spee, an admiral during [[World War I]]

==Description==
'''Admiral Graf Spee''', a 12,340-ton ''Deutschland'' class armored ship built at Wilhelmshaven, Germany, was commissioned in January 1936. She and her two sisters, ''Deutschland'' and ''Admiral Scheer'', were constructed as ''panzerschiff'' ("armored cruisers"), of a type in size and protection between a light and heavy cruiser, but carried heavier guns (eleven-inch) than contemporary foreign cruisers; the size of these guns and their turrets relative to their overall structure of the ship was such that all three were informally called “pocket battleships.” They were propelled by diesel engines that provided extraordinarily long range, though with a maximum speed (about 29 knots) that was somewhat slower than most cruisers. Largely designed as oceanic commerce raiders, it was expected that they could outgun almost any opponent that could not be outrun.

==History==
Following shakedown ''Admiral Graf Spee'' was, for a few years, flagship of the German fleet. During 1936-1938 she made training cruises in the Atlantic and Baltic, served off Spain during that Nation's civil war, and, in May 1937, was present off Spithead during the Coronation Naval Review held in honor of British [[King George VI]]. In April and May 1939 she participated in German naval exercises in the Atlantic.

As political tensions in Europe aproached a climax in mid-August 1939, ''Admiral Graf Spee'' again left Germany for the south Atlantic, where she remained hidden as World War II began early in the following month. Beginning in late September she cruised actively against British shipping in the Atlantic and Indian Oceans, capturing and sinking nine ships and causing Germany's opponents a great deal of anxiety and effort. On 6 December she rendezvoused with the supply ship ''Altmark'', which had kept her supplied with fuel during her raiding operations, then headed for [[South America]], where rich hunting among enemy merchant ships was expected.

==Battle of the River Plate==
At dawn on 13 December 1939 ''Admiral Graf Spee'', cruising toward Rio de la Plata (River Plate) in search of enemy merchantmen, sighted distant masts. Twenty-three major warships were actively hunting for her. Now the two sides were about to meet, for those masts belonged to three British cruisers, ''Exeter'', ''Ajax'' and ''Achilles'' (the latter part of the Royal New Zealand Navy). Initially thinking these were merchant vessels, ''Admiral Graf Spee's'' Captain Hans Langsdorf headed for them, continuing his approach once their true nature was known.

British Commodore Henry Harwood, on board ''Ajax'', also steamed toward his enemy. The opposing ships closed rapidly to gunfire range, with shooting beginning at just under 20,000 yards. Harwood divided his force, complicating Langsdorf's gunnery, but both sides began hitting early. ''Exeter'' was very seriously damaged by the German's eleven-inch guns: both of her forward eight-inch gun turrets were knocked out, her bridge crew was largely killed or wounded and fires raged amidships. She gamely remained in action until her remaining turret would no longer function. ''Admiral Graf Spee'' had also been repeatedly struck by Exeter's shells, and by six-inch projectiles from the other two cruisers. She laid a smoke screen and turned away, firing on ''Ajax'' and ''Achilles'', and disabled two of the former's gun turrets.

An hour and twenty minutes of intense combat was followed by a long day's pursuit as ''Admiral Graf Spee'' headed for [[Montevideo]], [[Uruguay]], harried by ''Ajax'' and ''Achilles''. She arrived just after midnight on 14 December and requested time to make repairs, reporting to the Uruguayans that she had been hit some seventy times. The British decided to keep the German warship in port as long as possible so they could bring up reinforcements. To this end they resorted to diplomatic trickery and broadcast misleading reports that the carrier ''Ark Royal'' and battle cruiser ''Renown'' were nearby. Captain Langsdorf, with much of his ammunition expended and his ship damaged, was soon persuaded that escape was impossible. After consulting with the German Government, in the early evening of 17 December he took his ship out into the broad river and blew her up, completely demolishing ''Admiral Graf Spee's'' after portion and leaving her a sunken, burned-out wreck.

Her crew went to [[Argentina]] where, on the night of 19-20 December 1939, Captain Langsdorf took his own life. The Battle of the River Plate, first of World War II's many great sea battles, greatly boosted British prestige and morale, but at considerable cost. The badly injured ''Exeter'', initially thought not worth repairing, was out of the war for fifteen months. Repairs to ''Ajax'' lasted until mid-1940.

''Admiral Graf Spee's'' shattered wreck has remained there ever since, partially visible in the shallow water. Recently (beginning in 2004) a group based in Uruguay has salvaged some of her weapons and fittings.

{| style="width: 100%; background:transparent; border: 2px solid #000099;" cellspacing="0" cellpadding="1"
!colspan=2 style="width: 100%; text-align: center; background-color: #000088; color: white; "|'''Copyright Details'''
|-
!style="background-color: #000088; color:white;"|License:
|style=" background-color: none;"| This work is in the [[Public Domain]] in the United States because it is a work of the United States Federal Government under the terms of Title 17, Chapter 1, Section 105 of the U.S. Code
|-
!style=" background-color: #000088; color:white;"|Source:
|style="background-color: none;border-top: 2px solid black"| File available from the {{{1|[[United States Federal Government]] [http://www.history.navy.mil/photos/sh-fornv/germany/gersh-a/grf-spee.htm]}}}.
|}

[[Category:Cruisers]][[Category:World War II]]

Talk:Regular polygon

2008-02-22T18:24:04Z

Sepura: Query about enneagons

== Mistake? ==

"Gauss ... showed that a regular n-sided polygon can be constructed with ruler and compass if the odd prime factors of n are distinct Fermat primes." I'm not sure that this is right. According to [http://mathworld.wolfram.com/ConstructiblePolygon.html], an enneagon cannot be constructed with ruler and compass. [[User:Sepura|Sepura]] 13:24, 22 February 2008 (EST)

Richard Nixon

2008-02-22T15:11:15Z

Sepura: /* Watergate */ typo

{{President
|image=Nixon 30-0316a.jpg
|seq=37
|term_start=January 20, 1969
|term_end=August 9, 1974
|party=Republican
|vp=Spiro Agnew
|vp_dates=1969-1973)
|2vp=None
|2vp_dates=Oct.-Dec. 1973
|3vp=Gerald Ford
|3vp_dates=1973-1974
|previous=Lyndon B. Johnson
|next=Gerald Ford
|office2=vice
|seq2=36
|term_start2=January 20, 1953
|term_end2=January 20, 1961
|pres2=Dwight D. Eisenhower
|previous2=Alben Barkley
|next2=Lyndon B. Johnson
|birth_date=January 9, 1913
|birth_place=Yorba Linda, California
|death_date=April 22, 1994
|death_place=New York City
|spouse=Thelma Catherine "Pat" Ryan
|spouse2=
|religion=Quaker
}}

'''Richard Milhous Nixon''' was the 37th [[President of the United States of America]], serving from 1969 to 1974. He was the only U. S. President to resign the office. He also served as the 36th [[Vice President of the United States]] of America under President [[Dwight D. Eisenhower]] from 1953 to 1961.

In 1947, he was elected as a [[U.S. Representative]]. As a Congressman from [[California]], and as a member of the [[House Committee on Un-American Activities]], he investigated Communists and instigated the successful prosecution of [[Alger Hiss]], accused of espionage for spying for the Soviet Union during [[World War II]].

After two terms in the House, he was elected to the U.S. Senate in 1950.

After losing his first presidential race to [[John F. Kennedy]] by a tiny margin in 1960, he unsuccessfully ran for Governor of California in 1962, losing to incumbent Edmund G Brown.

In 1968 he was elected president, and was reelected in 1972 by a landslide, but resigned the presidency on August 9, 1974 due to a threat of impeachment by Congress for the [[Watergate Affair]]. The main impeachment charge was that Nixon obstructed justice by telling employees to mislead FBI investigators about the Watergate burglary.

== Childhood ==

Richard Milhous Nixon was born in Yorba Linda, California, on January 9, 1913. Soon after, his family moved to Whittier, California. Nixon's childhood years were not unusual for someone growing up in two small towns near Los Angeles. His parents, Frank and Hannah Nixon, were devout [[Quakers]] Nixon had four siblings and saw two of his brothers die from [[tuberculosis]]. Nixon grew up relatively poor, as his father earned a modest income from his gas station and grocery store. But due to these hard times, he established a quality of determination and strong work ethic. A good student and a hard worker, Nixon excelled scholastically at both Whittier High School and Whittier College.

== Education ==
Nixon attended [[Fullerton High School]], from 1926 to 1928, in [[Fullerton, California]], and later, [[Whittier High School]], from 1928 to 1930, in [[Whittier, California]].

He graduated second in his class from Whittier with honor in the study of [[Shakespeare]] and [[Latin]]. He was awarded scholarships to [[Harvard]] and [[Yale]] University, but declined due to his family's tenacious financial condition. He instead enrolled at [[Whittier College]], a local [[Quaker]] school, where he co-founded the [[Orthogonian Society]], a new organzation to the campus, geared towards working-class students. At Whittier, Nixon, a formidable debater, was elected freshman class president, and served as student body vice president in his junior year and president in his senior year. While at Whittier, he taught Sunday school at [[East Whittier Friends Church]] and remained a member all his life.

A lifelong [[football]] fan, Nixon practiced with the team, but played little. In 1934, he graduated second in his class from Whittier, and went on to [[Duke University School of Law]], where he received a full scholarship, was elected president of the Duke Bar Association, and graduated third in his class.

== Military Service ==
During World War II, Nixon served in the [[Navy]] as a reserve officer. He received his training at Quonset Point, Rhode Island and Ottumwa, Iowa, before serving in the supply corps on several islands in the South Pacific, commanding cargo handling units in the SCAT. There he was known as "Nick" and for his exceptional poker-playing skills, banking a large sum of money that helped finance his first campaign for [[Congress]]. He rose to the rank of Lieutenant commander and resigned in March, 1946.

== Presidency ==

President Nixon established the [[Environmental Protection Agency]] (EPA) and was the first President to visit the People's Republic of [[China]]. He appointed a conservative ([[William Rehnquist]]), two moderates ([[Warren Burger]] and [[Lewis Powell]]) and a liberal ([[Harry Blackmun]]) to the U.S. Supreme Court. Nixon was from a [[Quakers|Quaker]] family. His foreign policy as president was marked by détente with the [[Soviet Union]] and the opening of diplomatic relations between the United States and the [[People's Republic of China]]. [[Conscription]] into the U. S. military also ended early in Nixon's second term, when he supported abolishing the [[Selective Service Administration]]. This was somewhat controversial at the time, but can be seen as a vote of great confidence in our system as against that of the Soviets, to the extent that our army, like our society, didn't need to be bigger as long as it was better.

His centrist domestic policies combined conservative rhetoric and liberal action in civil rights, environmental and economic initiatives. Nixon considered himself to be a Keynesian, that is, his economic views were shaped by economist [[John Maynard Keynes]]. [http://www.lewrockwell.com/orig3/hein6.html] As a result of the Watergate affair, Nixon resigned the presidency in the face of likely impeachment by the United States [[House of Representatives]]. His successor, [[Gerald Ford]], issued a controversial [[pardon]] that allowed Nixon to avoid prosecution. Speaking in later life, Ford stated that he felt the pardon was needed to stop a terrible rift developing in American social life.

Nixon inherited the Viet Nam war with a promise to bring "peace with honor," one of his 1968 campaign slogans. His Viet Nam strategies included "Vietnamization," a policy aimed at reducing U.S. casualties and troops, while also convincing the American public that the Vietnamese people could assume the primary responsibility of waging war. To win support for the war among the [["silent majority,"]] Nixon pursued the [["politics of polarization."]] Instrumental to this cause was Nixon's first vice president [[Spiro T. Agnew]], who criticized opponents of the war as "nattering nabobs of negativism," and an "effete corps of impudent snobs." Nixon also sought to instill in the North Vietnamese the belief that he was volatile and unstable, and willing to use nuclear weapons in the war, a strategy known as the "madman scenario."

On 30 April 1970, ten days after announcing that 150,000 American troops would be withdrawn from Viet Nam in the following year, Nixon announced that U.S. troops had invaded Cambodia. This announcement brought widespread protests and violence on college and university campuses across the nation, including four deaths at Kent State University in Ohio and two deaths at Jackson State University in Mississippi. Many campuses shut down, some for the remainder of the academic year. The [[Paris Peace Accords]] were signed on 27 January 1973, signaling the beginning of the peace process that ended with the evacuation of the last American personnel two years later on 29 April 1975.

== Watergate ==

The event that ended the Nixon presidency began on June 17, 1972, when five men, all employees of Nixon's reelection campaign, were caught breaking into rival Democratic headquarters at the Watergate complex in Washington, DC. The intruders and two other accomplices were convicted of burglary and wiretapping in Jan. 1973. The [[Watergate affair]] ultimately caused Nixon to resign on 9 August 1974. On 9 September 1974, his successor Gerald Ford granted him "a full, free, and absolute pardon." This effectively ended investigation into the depth of Nixon's involvement in the break-in at [[Democratic National Committee]] headquarters in the Watergate hotel, or any other criminal activities. Former White House Counsel John Dean testified to a Congressional investigating committee of Nixon's involvement in the cover-up.

The Congressional hearings revealed Nixon had tape recorded conversations and telephone calls in his office. These recordings reveal that Nixon's role in the cover-up began as early as six days after the break-in. The tapes also reveal an immense scope of crimes and abuses that predate the Watergate break-in. These include campaign fraud, political espionage and sabotage, illegal break-ins, improper tax audits, illegal wiretapping on a massive scale, and a secret slush fund laundered in Mexico to pay those who conducted these operations. The president, citing [[Executive Privilege]], refused to turn the tapes over to the committee. In Oct. 1973 Nixon ordered Elliot Richardson, the attorney general, to fire Archibald Cox, the special prosecutor who had subpoenaed the tapes, but Richardson resigned in protest. Richardson's assistant, William Ruckelshaus, also refused to fire Cox and was fired by Nixon. Finally, Solicitor General Robert Bork fired Cox. The incident, which was trumped in the press as the "Saturday Night Massacre" led to widespread calls for Nixon's impeachment.

The White House released edited transcripts of the tapes in April 1974, and eventually the tapes themselves, after the Supreme Court rejected Nixon's claim to executive privilege. The House Judiciary Committee issued three articles of impeachment on July 30, 1974.

"In all of this," the articles of impeachment summarize, "Richard M. Nixon has acted in a manner contrary to his trust as President and subversive of constitutional government, to the great prejudice of the cause of law and justice, and to the manifest injury of the people of the United States." After conferring with Republican Senators Nixon resigned on Aug. 9, 1974. Nixon was succeeded in office the same day by Ford.

== Writings ==

*Victory Without War, New York, NY: Pocket Books, 1989.
*Beyond Peace, New York, NY: Random House, 1994.
*Four Great Americans: Tributes Delivered by President Richard Nixon. Garden City, NY: Doubleday, 1973.
*In the Arena: A Memoir of Victory, Defeat, and Renewal, New York, NY: Simon & Schuster, 1990.
*Leaders New York, NY: Warner Books, 1982.
*Nixon in Retrospect, 1946-1962: Selected Quotations. Silver Spring, MD: Research Data Publishers, 1973.
*No More Vietnams, New York, NY: Arbor House, 1985.
*Real Peace. New York, NY: Simon & Schuster, 1990.
*RN: The Memoirs of Richard Nixon, New York, NY: Simon & Schuster, 1990.
*Seize the Moment: America’s Challenge in a One- SuperpowerWorld. New York, NY: Simon & Schuster, 1992.
*Setting the Course; The First Year, New York, NY: Funk & Wagnalls, 1970.
*Six Crises. New York, NY: Simon & Schuster, 1990.
*Summons to Greatness: A Collage of Inspirational Though and Practical Ideas from the Messages and Addresses of Richard Nixon, Thirty-:Seventh President of the United States, Washington, D.C.: Friends of President Nixon, 1972.
*The Real War, New York, NY: Simon & Schuster, 1980.

{{DEFAULTSORT:Nixon, Richard}}
[[Category:Presidents of the United States]]
[[Category:Vice Presidents of the United States]]
[[Category:Authors]]
==External Links==

*[http://www.nixonfoundation.org Nixon Birthplace & Library], in Yorba Linda, California

http://www.whitehouse.gov/history/presidents/

http://www.nixonfoundation.org/

http://www.nixonlibrary.org/
{{USPresidents}}
{{USVicePresidents}}

Talk:Tides

2008-02-22T13:37:40Z

Sepura: /* Two tides per day */

== Two tides per day ==

"Tides on the Earth result from the Moon's gravity, which is just enough stronger on the near side of the earth to attract ocean water more than on the far side." But there's a high tide on the side of the Earth facing away from the Moon as well. How does this thoery explain that? [[User:Sepura|Sepura]] 12:36, 21 February 2008 (EST)

:The entire earth is pulled slightly towards the moon, with the far side of the earth being pulled least, which is why there is a tide on both sides. Water, being a fluid, reacts more than the solid portions of the earth, but tidal forces affect the entire earth. Still not wording it well, am I? Oh well, that is why I am putting this on a talk page, not on the article page <grin>.[[User:Boomcoach|Boomcoach]] 12:57, 21 February 2008 (EST)

::"Water, being a fluid, reacts more than the solid portions of the earth" - are you saying that water experiences a stronger pull of gravity than solid objects? [[User:Sepura|Sepura]] 08:37, 22 February 2008 (EST)

Talk:Tides

2008-02-21T17:36:34Z

Sepura: New page: == Two tides per day == "Tides on the Earth result from the Moon's gravity, which is just enough stronger on the near side of the earth to attract ocean water more than on the far side."...

Reciprocal

2008-02-21T16:21:39Z

Sepura: typo

A '''reciprocal''' in [[mathematics]] is the inverse of a number.

For example, the '''reciprocal''' of 5 is 1/5th, or 0.20. The reciprocal of 100 is 1/100th, or 1%.
[[category:mathematics]]

Falsifiable

2008-02-21T16:17:05Z

Sepura: typo

A proposition or theory is '''falsifiable''' if it can be shown to be false when it is false. A proposal or theory that can never be shown to be false even though it is false is not falsifiable.

For example, the suggestion that I would be a very happy if I were ten years younger is not falsifiable, because I lack the ability to test the hypothesis by making myself ten years younger and seeing how I feel.

Falsifiability is commonly used as a criterion for whether a particular proposition is "scientific." Philosopher [[Karl Popper]] popularized this criterion, arguing that science progresses through the process of "Observation, speculation, falsification;" That is, we observe the universe, we develop a speculative hypothesis about the universe, and we test our hypothesis. If our hypothesis is proven false, we discard it. If our hypothesis is not proven false, we can consider it provisionally true. According to Popper, there is no such thing as ''scientific certainty;'' on the contrary, all our beliefs are properly held ''provisionally,'' and always subject to the possibility that they will somebody be disproven by experiment.

Popper, and those who agree with him, categorize many types of ideas as unfalsifiable, particularly in psychology and religion. For example, the proposition "Joe beats his children because his father beat him" is unfalsifiable, because we cannot perform a test in which Joe was ''not'' beaten by his father, and see if Joe still beats his children. Because the proposition is not testable, according to falsificationism, it is no better than any other hypothesis, and therefore not useful, and not scientific.

==Carl Sagan==

In his book, ''Demon-Haunted World'' [[Carl Sagan]], a noted [[astronomer]], gives an example of a statement with this sort of premise saying: "There is a dragon in my garage." In order for one to prove or disprove the statement they are allowed to ask questions.

*''Q. Can I see the dragon?''
*A. No, the dragon is invisible.

*''Q. Can I touch the dragon?''
*A. No, my dragon is incorporeal.

*''Q. Can I hear the dragon?''
*A. No, my dragon is silent.

and so on...

In this way, every question can be answered and therefore the existence of the dragon is unfalsifiable. However, in the absence of physical or other evidence of its existence, whether the dragon actually exists or not is a matter of faith.

== G.K. Chesterton ==
[[G.K. Chesterton]], a Christian [[Christian apologetics|apologist]] of the early 20th century, articulated the problem of falsifiability several years before Popper. He wrote:<ref>G.K. Chesterton, ''Everlasting Man'', II.</ref>

{{QuoteBox|Science is weak about these prehistoric things in a way that has hardly been noticed. The science whose modern marvels we all admire succeeds by incessantly adding to its data. In all practical inventions, in most natural discoveries, it can always increase evidence by experiment. But it cannot experiment in making men; or even in watching to see what the first men make. An inventor can advance step by step in the construction of an aeroplane, even if he is only experimenting with sticks and scraps of metal in his own back-yard. But he cannot watch the Missing Link evolving in his own back-yard. If he has made a mistake in his calculations, the aeroplane will correct it by crashing to the ground. But if he has made a mistake about the arboreal habitat of his ancestor, he cannot see his arboreal ancestor falling off the tree. He cannot keep a cave-man like a cat in the back-yard and watch him to see whether he does really practice cannibalism or carry off his mate on the principles of marriage by capture. He cannot keep a tribe of primitive men like a pack of hounds and notice how far they are influenced by the herd instinct. If he sees a particular bird behave in a particular way, he can get other birds and see if they behave in that way; but if he finds a skull, or the scrap of a skull, in the hollow of a hill, he cannot multiply it into a vision of the valley of dry bones. In dealing with a past that has almost entirely perished, he can only go by evidence and not by experiment. And there is hardly enough evidence to be even evidential. Thus while most science moves in a sort of curve, being constantly corrected by new evidence, this science flies off into space in a straight line uncorrected by anything. But the habit of forming conclusions, as they can really be formed in more fruitful fields, is so fixed in the scientific mind that it cannot resist talking like this. It talks about the idea suggested by one scrap of bone as if it were something like the aeroplane which is constructed at last out of whole scrapheaps of scraps of metal. The trouble with the professor of the prehistoric is that he cannot scrap his scrap. The marvellous and triumphant aeroplane is made out of a hundred mistakes. The student of origins can only make one mistake and stick to it.}}

== See also ==
*[[Falsifiability of evolution]]
*[[Deduction]]
*[[Induction]]
[[category:science]]
[[category:philosophy]]
== Reference ==
<references />

Talk:Powers of ten

2008-02-21T13:33:13Z

Sepura: So any number is a power of 10?

The table on the page is incomplete and incorrect.
Some Issues:
# The powers of ten seem to stop at 9, and clearly need to go up in threes.
# Traditionally, the English system of numbering has been as follows:
* thousand = American thousand 10^3
* million = American Million 10^6
* thousand million = American Billion 10^9
* billion = American Trillion 10^12
* thousand billion = American Quadrillion 10^15
* million billion = American Quintillion 10^18
* thousand million billion = American Hexillion 10^21
* trillion = American Heptillion (or Septillion) 10^24

However, it should be noted that the English system has now fallen into disuse and the American system of numbering is almost universally used.

--[[User:AvengingAngel|AvengingAngel]] 18:50, 27 April 2007 (EDT)

== So any number is a power of 10? ==

"Powers of ten are numbers of the form: 10X where x is an arbitrary real number" - on that basis, all numbers are powers of 10. [[User:Sepura|Sepura]] 08:33, 21 February 2008 (EST)

Talk:Prime number

2008-02-20T18:21:07Z

Sepura:

== Primality testing - Problems with the number 4 ==

When testing whether a number ''N'' is divisible by ''s'', using values of ''s'' from 2 to ''N'' - 1, when ''N'' is 4, the method correctly determines that 4 is not prime, because it is divisible by 2. This example is in the C programming language.
<blockquote><pre>
for (s = 2; s < N - 1; ++s) {
if (N % s == 0) {
printf("N is not a prime number.");
}
}
</pre></blockquote>

However, when using values of ''m'' from 2 to the square root of ''n'', when ''n'' is 4, an error can occur. Since 2 is the square root of 4, the test range is 2 to 2, and, if the range is exclusive, as in a for-loop, the whole test is skipped, and 4 is incorrectly determined to be a prime number.
<blockquote><pre>
for (s = 2; s < sqrt(N); ++s) {
if (N % s == 0) {
printf("N is not a prime number.");
}
}
</pre></blockquote>

[[User:Isaac4given|Isaac4given]] 11:28, 10 January 2008 (EST)

I'm surprised that 9 worked. Try.
<blockquote><pre>
for (s = 2; s <= sqrt(N); ++s) { // less than or equal to catch perfect squares
if (N % s == 0) {
printf("N is not a prime number.");
}
}
</pre></blockquote>

[[User:Ga ohoyt|Ga ohoyt]] 13:32, 10 January 2008 (EST)

== Flaw in proof ==

"It is easy to prove that there are an infinite number of primes using Euclid's second theorem. If there were a finite number of primes, you could multiply them all together and add 1. The resulting number would show the existence of a new prime, since it would not be divisible by any smaller prime (it would always have a remainder of 1)." This argument doesn't work. 510511 = 2 * 3 * 5 * 7 * 11 * 13 * 17 + 1, but it's not prime. [[User:Sepura|Sepura]] 13:21, 20 February 2008 (EST)