The half life of a radioisotope is the time taken for the current level of radioactivity to drop to half that amount. Note that this means radioactive decay follows the curve of a decaying exponential. Oh, as mentioned, it is also somewhat of a revolutionary computer game. "As for the suit, I think you've earned it"
Carbon-14 has a half-life of 5,730 years. Let's say its radioactivity 'level' at time = 0 is 2. After around 5,730, its radioactivity will be 1, After a further 5,370 years its radioactivity will be 0.5, and after yet another half life, the radioactivty would be 0.25, and so on.
by Chavez77 June 22, 2006
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Released on October 31, 1998, Half-Life is a first-person shooter for the PC. It is widely considered as one of the greatest shooters ever made due to its expansive world, story, and delivery of gameplay. The game includes no cut-scenes or dialogue text, helping you engross in the game as if you were really in it. Almost all shooters of today take something from Half-Life, Halo as a good example. Even 8 years after its release, people still play and create MODs for it, Counter-Strike being the most popular. It has had a long awaited sequel released in 2004.

The historical importance of the game in video gaming will remain as long as shooters exist. It was the first FPS to not have levels or stages and the first to not introduce you with a weapon at the start (you begin on a tram on your way to work-- an ordinary day gone wrong to say the least). Gamespy awarded Half-Life with the second best game ever made, and PC gamer declared it as the best PC game as of 1999.
"Half-Life is the closest thing to a revolutionary step the genre has ever taken. -Gamespot"

"Nothing half-assed about it--this has to be the finest shooter ever crafted. -IGN.com"

"Everything about Half-Life smacks of quality: the storyline, the gameplay, the graphics, the sound effects and last, but not least, the obvious level of committment Sierra and Valve have invested in it. Half-Life is, without doubt, the best PC game I have ever played. Ever. -Yahoo! Games"
by Sharkhunter August 27, 2006
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Anthony hates Half-life

Eighth grade girls delayed half-life 2. Kill them
by bladeguy4543 May 26, 2004
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1 : the time required for half of something to undergo a process: as a : the time required for half of the atoms of a radioactive substance to become disintegrated b : the time required for half the amount of a substance (as a drug or radioactive tracer) in or introduced into a living system or ecosystem to be eliminated or disintegrated by natural processes
2 : a period of usefulness or popularity preceding decline or obsolescence <slang usually has a short half-life>
For americium-241, it is known that half of the atoms decay in 458 years. Therefore, 458 years is the half-life of americium-241. Every radioactive element has a different half-life, ranging from fractions of a second to millions of years, depending on the specific isotope. For example, americium-243 has a half-life of 7,370 years.
by Mark January 6, 2004
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Valve's Half-life is one of the best games, and one of the best game series, to grace the Steam library. It was revolutionary, and not only proved that mindless shooters can have a compelling story.

Half-life 2, proved that good physics can be a vital asset to shooters/ With the inclusion of the Gravity gun, one of the series most iconic weapons, the Source physics engine is put to the test, being able to launch entire boxes, and barrels, and throw them an insane distance.

The music is an integral part of the series. It puts some extra flavor on everything. Like when you come upon a very eerie setting like Ravenholm, creepy music begins. Or when you get thrown into a HECU ambush, or a Hunter-Chopper chase, amazing action packed music starts playing.

Something that helped take off the series was the inclusion of a silent protagonist, Gordon Freeman. Giving the player a character that only makes decisions that the player makes, means that you don't get to see a story though the character's eyes, you are the character. This stays pretty much the same through out the entire series. And not to mention that so many things came out of these games. Such as Counter-strike, Team Fortress 2, or even Garry's Mod, even though it's not a Valve game, it was built directly off of Half-Life 2.

And I can go on for hours, but you've probably got better things to be doing, like school work. But I don't blame you. School is terrible.

Long story short: Half-life is fucking amazing.
Guy 1: Hey man. What's you favorite game?
Guy 2: Half-life. Easy.
Guy 1: Nice.
by Nephilis Thylord November 30, 2020
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1:
Half the time it takes for a radioactive substance to decay.

2:
Extreamly popular game, developed by the company VALVe. Yeah, that's how you spell it. With those capitals and that lower-case e.

The game is extreamly popular, boasting an impressive AI and great graphics (for its time). The mod community made that even better, with one of its best mods, Counter-Strike, being able to go commercial and make a profit. This, in turn, started getting people to think of the OTHER great mods in the mod community, namely Sven Coop, Day of Defeat, and The Specialist are all mods that come to mind.
Damn, this game is huge! I've been playing this since 1998, and it's still fun! Thanks mod community, and thanks VALVe!
by Brakman October 8, 2004
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Half-Life is about a guy, Gordon Freeman. He went to Black Mesa and worked at the test chamber, something went wrong, aliens started comming and trying to destroy Black Mesa. Your job is to go to the surface and meet up with Milatary Forces. But the government ordered the Milatary to kill the aliens, but also the workers of Black Mesa! Your next job is to go to Lamba Complex and telaport to Xen to destroy the big boss!
Fight all the aliens like Headcrabs, Vortigaunts, Zombies, Soldiers, and more enemies you will face, get weapons to defend yourself and save Black Mesa from the Xen Wildlife. This is Half-Life!
by Mega Sean 45 June 18, 2008
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