Since the beginning of the anime, the Poké Ball was shown to have two sizes. A very small one, for storage, having the size of a ping pong ball; and the bigger size, when the ball is about to be used for any purpose (releasing, capturing, retrieving, transferring, etc.), having the size of an orange. The default size of a Poké Ball is the small one, when it's technically inactive. To make it "grow", and therefore, able to be used, the trainer needs to press the button on the center to activate it. When the Poké Ball has been used it automatically returns to its original size. Though, it was sometimes shown in the anime that inactive Poké Balls were in the bigger size. In the Wasabi Peas manga, Kitsuki's Poke Ball is strictly the size of a marble.
Inside, the Poké Ball features many of what appear to be mirror panels. The inside of a Poké Ball is supposedly designed to make the Pokémon feel as comfortable as possible while inside it. While never fully explained in the anime, manga, or core video games, Super Smash Bros. Melee states that this is done by creating a holographic environment that suits the Pokémon. However, the anime has shown examples of Pokémon that do not like being in their Poké Balls; a notable example is Ash's Pikachu. In the first episode of the series when Ash tries to get his Pikachu to go into the ball, it refuses. Ash says that Pikachu should go in because that's what all Pokémon are expected to do, having his Pokédex state this for confirmation. However, Pikachu presses another button on the Pokédex to give more information on the subject and it is revealed that some Pokémon do not like feeling confined which might show a pokemon's fear of being in closed places.
In the Pokémon world, scientists have been using various, highly developed techniques of converting matter into energy and back for years. The Poké Ball is a quintessential example of this technique. When a Poké Ball is thrown at a Pokémon and comes into contact with it, the ball flips open. In the anime, the button on the Poké Ball must touch the Pokémon in order for it to be captured. The ball converts the Pokémon and any attached items into energy (represented in the anime as a dim red light, but usually portrayed as a flash of stars, bubbles, etc. in the various games), and sucks it inside, closing automatically in the process. The Pokémon will likely struggle, trying to break free. If the Pokémon has been sufficiently weakened in battle and/or the Poké Ball model is sufficiently strong, the Pokémon is captured and used by the trainer. In the games, if the Pokémon frees itself, the Poké Ball is irreparably broken; in the anime, it rebounds to the trainer.
In the anime and core games, humans cannot be caught with Poké Balls, but small inanimate objects such as rice balls, rocks, etc. have been caught in Poké Balls for comedic effect early in the anime's history. In fact, it seems to hurt humans when a Poké Ball mistakenly tries to capture them (Jessie of Team Rocket gets painfully shocked when protecting a Sudowoodo from a Poké Ball). In the Manga, it was briefly discussed that Poké Balls aren't powerful enough to capture a human, but if a human was to be captured the ball would "correct" the mistake by turning the human into a various Pokémon, though this concept has never been seen in action.
Also, when a Poké Ball is used to capture a Pokémon, the ball will only recapture that Pokémon, and the Pokémon will enter only to that Poké Ball. A possible and only exception to this rule are the black Poké Balls Mewtwo created in Pokémon: The First Movie, which capture other trainer's Pokémon, as well as capture occupied Poké Balls. If the Poké Ball gets damaged or broken, the Pokémon will be automatically released and stay free until the ball is repaired. An example of this was when Ash's Snorlax's Poké Ball was broken, and the party had to carry the heavy Pokémon to the nearest town, in the back of a great hill.
To retrieve the Pokémon, either because it was knocked out or the trainer wants to give it a rest, the Poké Ball is held with the button pointing at the Pokémon. The Poké Ball does not open this time. The energy from the Pokémon goes through the button to the inside.
The difference between calling out and retrieving, besides than the ball not opening when calling the creature back, is the energy of the Pokémon. When capturing or retrieving, the energy is dim red, but when calling out (and evolving) the energy is pure white and intense.When a Pokémon is released (i.e, given up) the energy is blue.
Storing the Poké Balls themselves, with or without Pokémon in them, involves a specialized computer, or "PC". In the game and the anime, whenever an official Trainer has six Poké Balls containing Pokémon with him or her, additional captured Pokémon and their Poké Balls are immediately teleported automatically to their registered Pokémon Computer Storage System. In the anime, Brock explains that the Pokédex is the mechanism keeping track of a trainer's Pokémon and is responsible for the instantaneous storage of new Pokémon caught past the six. How this transport system technically works is not specifically explained, but it is assumed that it uses the same matter-energy technology present in the Poké Balls themselves. It also doesn't address how trainers without a Pokédex, such as Brock himself, store their Pokémon. In the movie Pokémon: Destiny Deoxys, it is revealed that all Poké Balls are registered to a managing system. When LaRousse City was isolated from the rest of the world by Deoxys's force field, the blackout caused the trainers' Poké Balls to fail, making them unable to release or return their Pokémon.
Not only Pokémon can be "energized", practically any item, no matter how heavy, can be converted into energy and back. This makes Poké Balls practical in the storage of some of a trainer's bulkier items. In the anime, a Poké Ball was wasted when it captured a rice ball (or doughnut due to cultural localization during translation). In the games, many items are found in Poké Balls. When picked up, these balls are not added to one's current stock of usable Poké Balls, since they have been used already to capture those items. Like the Pokémon Computer Storage System, one's items can be transported to and from a properly equipped PC, and it is an important part of the gameplay. However, this feature has been scrapped in the newest games in the series, Pokémon Diamond and Pearl, since the player's bag, which serves as his or her inventory, is now capable of holding as many items as the trainer needs. In previous Pokémon games, the bag had limited capacity. Since this change, the PC at the player's house only shows a beginner tip; in the past, it was the player's own PC that stored items.
In the anime depiction, Pokémon already belonging to a specific ball can be returned to it with a laser emitted from the expansion button on the Poké Ball. Originally, the Poké Ball opened to allow the recalled Pokémon to enter. This was later changed so that a recalled Pokémon enters through the expansion button. This is more convenient in recalling Pokémon from battle rather than having the respective Pokémon contact the ball itself. As with any laser however, obstructions can prevent the laser from recalling the Pokémon. Lifeforms that are hit with the laser but do not belong to that certain Poké Ball will feel a slight paralyzing effect. Jessie of Team Rocket was the first to experience getting hit by the Poké Ball laser. Nevertheless Jessie had to be carried away by her friends. All Jessie could respond was: "So that's what it feels like..."
In power plants, the Poké Ball may turn out to be a Voltorb or Electrode in disguise, attacking Trainers when picked up. In the games Pokémon Colosseum and Pokémon XD: Gale of Darkness, items are found in box-like containers designed to look like Poké Balls. These differ not only in shape but also in the fact that they are able to contain multiple items.
Kurt, a non-player character from Pokémon Gold, Silver and Crystal who is referred to as an expert or "Poké Ball master" in the game and anime, explains that Poké Balls were originally made by fitting a special device in a hollowed-out Apricorn, but later began being made of synthetic materials and mass-produced by large companies such as Silph Co. in Kanto. Other than the simple basics on how a Poké Ball is used and how it functions, the advanced internal functions of a Poké Ball are never fully explained.
Various anime episodes and movie titles either contradict this history, or expand upon it. In Pokémon 4Ever, which is partially set in the past, one of the characters uses a non-synthetic Poké Ball which neither looks nor functions like any of Kurt's Apricorn Balls; it is opened by unscrewing the disproportionate top. The anime episodes (which included a paralleled history of Poké Balls in an episode with Kurt titled "Goin' Apricorn") tend to focus on ancient civilizations and the ways that they dealt with Pokémon capture. However, even these episodes can contradict each other, as some devices closely resemble the modern synthetic balls, while others do not. In the anime episode "The Ancient Puzzle of Pokémopolis" giant ancient Pokémon appear to have been stored in simple stone talismans. For example, a giant Alakazam comes out of an ancient spoon, and returns back to it in a manner very similar to modern Poké Balls. Contrarily, in the episode "Claydol Big and Tall", a giant Claydol was contained within a similarly giant-sized ancient stone Poké Ball. In Lucario and the Mystery of Mew, Lucario is trapped in a staff similarly to how a Pokémon could become trapped in a Poké Ball. It seems likely that different civilizations captured Pokémon in different ways.
In the anime, most trainers only ever use the regular Poké Ball. The only times another type of the basic four is seen is in episode #1, as who appears to be Bruno of the Elite Four, calling back a Nidorino and calling out an Onix from a Great Ball, and in episode #351, Whiscash and Ash, in which a self-proclaimed "Legendary Fisherman" tries to capture the titular Whiscash with a Master Ball. He ironically fails when the Whiscash swallows the ball after it's thrown. However, in a later episode, Munchlax eats the Poké Ball thrown at it, but is then captured from the inside-out.
In the second-generation games Gold, Silver, and Crystal, players can win more Master Balls at the Goldenrod City's Radio Tower. In the third-generation games Ruby, Sapphire, and Emerald, players can win more Master Balls at the Lilycove City department store lottery. One additional Master Ball lies in the hideout of antagonistic Team Magma (in Ruby) or Team Aqua (in Sapphire). In fourth-generation games Diamond and Pearl, Master Balls are obtainable at the Jubilife TV tower after winning the in-game lottery, or by beating Cyrus the first time.
In the games, it is referenced that the Master Ball is seldom used by ordinary Trainers. Normally they are restricted to researchers who must get them through special order.
The Master Ball first appeared in episode 352, "Whiscash and Ash," when a fisherman was using one to try to catch an oversized Whiscash. The Master Ball failed in a comical fashion; it was eaten by the Whiscash, much to everyone's horror.
It seems that Ash owns a beach ball that looks like a Master Ball (as seen in several episodes having to do with or revolving around water).
The Johto games were also the first to offer a history for Poké Balls, explaining that before the creation of synthetic materials people in the Pokémon universe used Apricorns. This fictional history maintained its continuity with the concurrent anime in which the main characters hear the same story from the same Poké Ball creator, Kurt. In Japan, where mobile phone linking was made available for Pokémon Crystal, players could obtain a GS Ball by utilizing their mobile phone to link with other players. After letting Kurt examine the mysterious Poké Ball, the player will be prompted to visit Ilex Forest and "find out what is wrong". There, players can place the GS Ball in the Ilex shrine and encounter a level 30 Celebi, which is one of the Legendary Pokémon for the Johto region.
Through the course of a few episodes, the trainers learn about the various Apricorn Balls available and are each given a Fast Ball in addition to one other type of their choosing. Fast Balls are used to catch Pokémon that try to escape quickly, and Brock uses his to catch a Pineco in Goin' Apricorn (#145). Ash and Misty also each receive Lure Balls, a type of ball that makes catching Water-type Pokémon easier. They try to use theirs at the same time when capturing a Totodile in The Totodile Duel (#153) and since they cannot determine whose ball actually caught it, they have a battle, with Ash as the winner. Misty later uses the leftover Lure Ball in The Corsola Caper (#215) to capture the pink "coral Pokémon". They both have yet to use their Fast Balls they first received. These rare balls don't make an appearance again until the Advanced Generation series in episode #341, Gulpin it Down. In this episode both a Gulpin and Ash's Treecko become giant sized in a freak accident and stage a Godzilla-esque battle which the Treecko wins. While the Gulpin is recuperating, the scientist responsible for the accident uses a Heavy Ball to capture it. Heavy Balls work more effectively the heavier the Pokémon is, so in this case it was the perfect choice.
The Park Ball makes a reappearance in Pokémon Diamond and Pearl. These balls are used in a capture game that allows players to acquire Pokémon they previously owned on the Ruby, Sapphire, Emerald, FireRed, and LeafGreen game cartridges. Here, it has a 100% capture rate, due to the fact that the Pokémon involved should already belong to the player.
In the anime episode, The Bug Stops Here (#163), the Bug Catching Contest is played out according to the same rules in the GSC video games. Ash ultimately catches a Beedrill and wins the contest, but gives it to his friend Casey who happened to have entered the contest as well. In addition to mirroring the Park Ball, the anime built upon the idea of contest-specific balls and in an episode entitled Hook, Line, and Stinker introduced the Lake Balls which were given to Misty and Ash for use in a Seaking-catching contest.
The new Net Ball was created to replace the Lure Ball, and expanded its capabilities by proving more effective not only when the player has caught a Pokémon by fishing, but when they encounter any Water-type, or even Bug-type Pokémon.
A similar ball, the Dive Ball, exploited the new ability to dive underwater by making Pokémon found "on the ocean floor" more susceptible.
Two unique balls are the Luxury Ball and the Premier Ball. Both are colored very differently than other varieties - the norm being a variance on the top half of the ball only, as seen with the Master Ball and Apricorn Balls. The Luxury Ball is almost completely black with what looks like diamonds studded in the top and a gold band in the center, conversely the Premier Ball is completely white with a red band in the center. Neither of these balls are any more or less effective than a regular Poké Ball; while the Luxury Ball is the Hoenn counterpart to Johto's Friend Ball, the Premier Ball has the distinction of always being given away freely.
Another unique ball, the Cherish Ball, is not sold, found, or even obtained through normal gameplay. Instead, some Pokémon given out at special events, such as Darkrai, are housed in it. The only other way to get a Cherish Ball is to use an Action Replay DS. It prevents the Pokémon from being traded in the GTS. It shares the design of a Premier Ball in the sense that it is solidly colored, but in this case it is red. It also has what appears to be small indents in its sides. The Cherish Ball's only noticeable effect in battle is that it releases an array of different colors when it is thrown into battle.
Examples of this symbolic use include Team Rocket using various devices in the shape of Poké Balls that were designed to capture Pokémon or other things through unconventional means - often in the form of dispensing a net, or being connected to a large vacuum hose.
The Pokémon movies are a large source of the more unusual instances of Poké Balls. In the first Pokémon movie, Mewtwo Strikes Back, the titular character, Mewtwo, creates his own sort of black Poké Ball. These balls do not follow the same guidelines as others, allowing the capture of trainer-owned Pokémon, even those that are still within their own Poké Balls - thus capturing the Poké Balls as well. In the third Pokémon movie, a little girl named Molly creates a crystal version of the Poké Ball with psychic power borrowed from Unown. She uses this crystal Poké Ball to release crystal Pokémon into battle. Then in the fourth movie, Pokémon 4Ever, the villain, the Iron Masked Marauder, utilizes what he calls a Dark Ball in order to capture Pokémon and instill them with a more sinister personality. The Dark Ball is revealed to act as a Master Ball ,i.e. it catches any Pokémon without fail. In addition to this, it also gets the caught Pokémon to completely obey its owner, is automatically trained to the highest possible level, and is transformed to pure evil. It was demonstrated on a Tyranitar, and later used on a Celebi. This concept is similar to the one used with Snag Balls in Pokémon Colosseum and its sequel.
In addition, several Poké Balls are shown to be altered in some way to show their association with a particular group or purpose. Examples include Nurse Joy using a Poké Ball that vaguely resembles Chansey (the Pokémon most often seen running about Pokémon Centers in the anime), Team Rocket using name-branded balls in the movie Pokémon: Mewtwo Returns, and the Pokémon trading card game featuring various Poké Ball cards that are associated with Team Aqua, Team Magma, or the aforementioned Team Rocket.
The Poké Ball has even been subjected to gold-plating throughout its history in the anime. The most notable example being the beginning of a running gag which involved a salesman selling a gold-plated Poké Ball containing a Magikarp to James. James is conned into thinking the Poké Ball is pure gold and led to believe that he'll make a fortune selling the Magikarp's eggs. He spends the team's entire advanced salaries to make the purchase, only to find out that the whole plot is a pyramid scam. A fake golden Poké Ball is used again in "The Ribbon Cup Caper" when Officer Jenny spray paints a regular Poké Ball in order to catch a criminal.
In the television series, Ash obtains the GS Ball from a Pokémon researcher, Professor Ivy in the Orange Islands. He is instructed to deliver the ball to his hometown's own researcher, Professor Oak. The GS Ball is a great puzzle. It cannot be opened or teleported and no-one can tell whether it has a Pokémon inside. After Professor Oak is in turn unable to figure out the GS Ball, Ash journeys to Johto and delivers it to Kurt, the Poké Ball master, in whose care it apparently remains. While the GS Ball appeared to play an important role throughout the series - several random scenes were shown throughout various episodes of Ash studying it, trying to figure out its origin - the GS Ball turned out to be apparently little more than a meaningless plot device; but was supposed to introduce Celebi in the anime. The plot was abandoned in favor of using Celebi for the 4th movie.
When a Snag Ball is used, a large claw-shaped formation of energy comes out of the ball and entraps the target within. After the capture, a Snag Ball reverts back to a regular ball.
Poké Balls also appear in the next game of the series, Super Smash Bros. Brawl, using newer Pokémon like Groudon, Deoxys, Piplup and Munchlax. Additionally, Poké Balls are the main arsenal of the new character Pokémon Trainer (who is inspired by the FireRed and LeafGreen incarnation of Red, the main protagonist in many Pokémon games); using the item, he calls upon one of three Pokémon (Squirtle, Ivysaur, or Charizard [who previously appeared in the Super Smash Bros. series as a non-playable Poké Ball Pokémon]) to battle. The Poké Ball also appears as the symbol of Pikachu, Jigglypuff, Pichu, Mewtwo, Lucario and the Pokémon Trainer.
This was a specially modified ball used by Mewtwo, who changed what were believed to be normal Poké Balls to have a 100% catch rate, have an unlimited number of attempts (balls used in the video games only having a single attempt each), it could catch another pokemon while already in a pokeball, and could even levitate. These balls were programmed to travel to the cloning room on Mewtwo's Island after capturing the Pokémon, and then to clone the Pokémon inside. Cloning Pokémon creates for them feelings of distress and incompetenance. Forcing them to being evil.
In the game Pokémon Snap, Prof. Oak gives Pester Balls to Todd after he obtains a total score of 75,000 points for all of the pictures in the Pokémon Report. They help him flush out wild Pokémon, provoke an irritated reaction, and sometimes even knock them out of the way. Pester Balls have never been used in any other game.