TNT

TNT (or Dynamite) is an explosive block that is placed and can be subsequently activated at the player's discretion to deliver a powerful blast in a desired area. Its explosion is generally lethal to most players at close range.

TNT can be used in traps or to demolish unwanted structures.

Natural Occurrence
TNT occurs naturally in Desert Temple traps.

As a crafting ingredient
Can be activated by using an Activator Rail.

Activation


A TNT block can be activated by:
 * being right-clicked with flint and steel
 * a redstone current
 * being shot with a Flame-enchanted Arrow
 * being placed by a dispenser
 * coming into contact with spreading fire or lava
 * being in the blast radius of a nearby explosion, including that of another TNT block

TNT explodes following a short delay once activated. If the block was activated by redstone or fire, the delay will be 4 seconds; if it was activated by a neighboring explosion, the delay is shorter.

Both activated and non-activated TNT can be safely pushed with pistons. Like any other block, it will stop as soon as the piston is fully extended; it is not launched.

Behavior
Once activated, TNT begins its countdown timer. During the time between activation and explosion, TNT becomes an entity (Primed TNT) subject to physics, such as gravity. Activated TNT passes through other entities (but not solid blocks), notably including other primed TNT blocks.

When the timer expires, the TNT explodes. Nearly any blocks, mobs, and players caught in the blast radius will take damage or be destroyed/killed outright. TNT detonated in a liquid will not destroy blocks, but will damage players and mobs. Floating items hit by the blast will be destroyed, but will be shielded by any block in the way.

TNT explosions are CPU-intensive, so large explosions, and especially compound explosions from clusters of TNT blocks, can cause stuttering or even game crashes, depending on hardware. TNT will blow up 75% of all blocks around it, including the blocks under it and the dropped blocks near it.

Explosive force
The TNT blast will propagate according to the formula f=e-r, where f is the force of the TNT blast after propagating through the block, e is the energy of the blast before propagating through the block, and r is the blast resistance of the block. Thus, the explosion propagates farthest (7 blocks) through air, which has a blast resistance of zero. However, TNT immediately enclosed in stone will destroy an exact 3x3x3 cube originating from the center of the blast. The damage is usually lethal at close range.

Immune objects
Several blocks can survive TNT blasts, and will protect players shielded by them. These include Obsidian, Bedrock, liquid source blocks (with enough force lava source blocks will be destroyed), Anvils, Enchantment Tables, Ender Chests, and End Portal Frame blocks.

These allow for bomb shelters, a sealed world, and TNT Cannons. In addition, a player or mob sitting in a minecart will take minimal damage from a TNT explosion, and this effect allows them to be launched great distances.

Water as a blast controller
If a layer of water is spread between a destructible block and an explosion, the block will be protected. A one-block-thick water screen will stop most explosions from reaching the other side, however, a player laying multiple blocks of TNT should mind the placement of the explosives, as primed TNT entities may launch each other through the water screen. Using water this way lets you use TNT near an important area, such as a house, base, or ore vein.

Thus, a player can use this to dig a big quarry or hole precisely and quickly by placing a "curtain" of water on the extremities of said hole and dynamiting the center. A player could also make a TNT trap that drops TNT into a block of water, preserving the blocks around it but damaging or killing the mob that activated it.

Traps
TNT traps can be created by connecting them via redstone to Pressure Plates. Concealing the TNT in such a trap just below ground level effectively creates a land mine.

For TNT to receive a redstone circuit's signal, redstone needs to be directed straight into it from at least one of four sides, from either the Layer the TNT is based on, or above or below one layer. Diagonally adjacent entry will not make a connection. Redstone next to TNT will also set off the TNT, even if it is not directly connected with it (through a T connection not directly connected, or an "I" connection running parallel alongside it). TNT will not be set off immediately if current is activated prior to placement of the TNT. Redstone torches will activate a TNT block as well if directly under the TNT block, or under a block on which the TNT rests.

Other uses
TNT can be used to destroy monster spawners. They have a high blast resistance (25), but are easily destructible with a single block of TNT.

TNT can be used to view nearby caves/underground spaces (this is a common use, even though it is due to a bug). This is done by using pistons to push TNT into the space where the player is standing. Because TNT is transparent, this will not hurt you, but will allow you to see through all blocks that aren't adjacent to air. Glowstone offers the same bug/function, and may be a safer option.

TNT is useful in clearing large amounts of dirt or gravel when mining underground, or for clearing large volumes of underground area indiscriminately for underground building projects. However, since it will wind up destroying most dropped items, it is of no use in breaking blocks to collect their resources.

Also:


 * TNT Cannons: Because primed TNT is affected by physics, it can be used as a projectile that is propelled by another TNT explosion.
 * Rocket-jumping: TNT can be used to propel players, though heavy/enchanted armor will likely be required to survive the blast. With an adjacent water block and a well-timed jump, it may be possible to avoid damage.
 * Spleef arenas: Because they are destroyed in one hit, they work better than dirt or other materials and do not need a tool to be destroyed. This use depends on no player coming in with items that could be used to activate TNT; or else a plugin that disables explosions can be used.
 * Griefing

Primed TNT
Primed TNT is an entity. It is spawned at the center (+0.5,+0.5,+0.5) of a powered TNT block, while itself is a cube with an edge length of 0.98. Its fuse lasts 40 (redstone) ticks (4 seconds/80 game ticks) if activated by redstone or fire, or a random number between 10 to 30 game ticks (.5 to 1.5 seconds) if it's destroyed by an explosion.

Once spawned, primed TNT is given a vertical velocity of 0.2 m/tick, and a horizontal velocity of 0.02 m/tick in a random direction. If it does not collide with another block, it will travel 0.166m horizontally on flat ground before it stops and explodes.

When TNT is primed in light, it flashes white. In darkness, it flashes black.

Trivia

 * "TNT" stands for Trinitrotoluene.
 * In Beta TNT could be lit by breaking it.
 * An activated or "primed" block of TNT will fall 77 blocks before exploding.
 * Destroying TNT makes the same sound as destroying a grass block.
 * Like the arrows, primed TNT will catch on fire if it is shot through lava.
 * If a Spawn Egg is set to spawn Primed TNT using a mod, then an explosion will immediately follow when the egg is used. That is because the fuse is 0 ticks.
 * If TNT is blown up just as an arrow passes by, then the arrow is redirected opposite of the blast.
 * Detonating a large amount of TNT may cause Minecraft to severely lag or even crash.
 * To have a TNT block drop down and destroy blocks underwater, before the Redstone current is applied, a block of gravel should be added on top of the TNT. The gravel will fall with the TNT, the TNT will land below the water, and the gravel will land and form a block around the TNT, which will allow the TNT to destroy blocks underwater.
 * TNT is the only solid block that breaks instantly.
 * As of 1.2.5, if the player is standing in a 2 block deep by 1 block wide hole and has Sticky Pistons push TNT into him/her, he/she will be given an x-ray view of surrounding caverns. It can be used for locating Spawners and some exposed Ores ( not the veins, like in mods ). This can also be done with glowstone.
 * Although flint & steel cannot light fires in Adventure Mode, it can still ignite TNT.
 * While under the effects of a Potion of Night Vision, TNT will appear fullbright as usual, but will ignore the potion's effect and take on the light around it when primed, because it's an entity when it's primed.
 * If TNT, when primed, hops up and just barely lands on a block directly below and next to it,and then slides off, the TNT will fall, but the explosion will appear where the TNT almost landed before sliding off.
 * By combining TNT cannons and player launching devices, one can make a "firework base" that shoots TNT into the air, letting it explode like professional-grade fireworks in real life.
 * When the player primes TNT and the primed block falls into the end, the TNT block will detonate when the player enters the end. This gives the player an opportunity to detonate hundreds of TNT blocks instantaneously.
 * You can see primed TNT from about (at the most) 70 blocks away.
 * TNT is available for building in Pocket Edition creative mode, but it cannot be ignited because PE creative lacks flint and steel.
 * As of Official Release 1.5, Mobs killed by Player-ignited TNT (via Flint and Steel or by Flaming Arrows) will drop EXP orbs as though they were killed by the player in regular combat. This makes for effective EXP and Mob drop farming.
 * TNT ignited via Redstone signals or Fire will otherwise cause mobs to drop no EXP.
 * The crafting recipe for TNT (sand and gunpowder) may be a reference to the fact that early gunpowder was made by mixing powders together (sulfur, saltpeter and charcoal), and to the fact that Creeper gunpowder used to be called Sulfur. Real-life TNT is made by repeatedly treating toluene with concentrated nitric and sulfuric acids.
 * When primed TNT is directed towards a Nether Portal, it will only pass through said blocks and not travel into the Nether. (Tested with a TNT cannon).
 * Although primed TNT will get caught in Cobwebs, TNT propelled fast enough will fly through them without slowing down at all.
 * Theoretically, an infinite amount of primed TNT can fit into one cubic meter because primed TNT will not collide with other primed TNT. Falling sand and gravel entities will react accordingly to a detonation, scattering from the point of origin, and will fall through the TNT when it is triggered. If sand or gravel fall through primed TNT while it is underwater, the TNT will detonate normally, causing an explosion.
 * A consistent method of crashing Minecraft is to start a superflat world with a layer of TNT, then set it off. The number of concurrent explosions rises exponentially to infinity.
 * It takes 19.75 blocks to fall for it to reduce the timer for one second.