Let's have a look at what Pokeballs are.
"When drawn into the capture device, known as the Pokeball, Pokemon become portable. Thus, the appeal of Pokemon has spread to people throughout the globe. Although some have appropriated these containers to keep Pokemon as pets, the Pokemon contained within can be very dangerous... therefore, only fully licensed trainers and breeders are permitted to handle them.
Pokemon Handler's License - Applicants must be over 10 years of age and are requried to attend a half-day training session before qualifying to take a brief test. Those who pass this examination receive the license. Only licensed Pokemon Handlers may legally purchase Pokeballs."
(From "The Electric Tale of Pikachu".)
Pokeballs are fist-sized red-and-white balls that split open where the colour changes. A button can be used to open or close the ball, drawing a Pokemon in or releasing it, and can also be used to shrink the ball; you can fit one normal-sized ball in the palm of your hand, or a dozen shrunken ones.
A Pokeball contains a red energy that draws the Pokemon inside. When this energy beam hits the Pokemon that belongs to a Pokeball, it will draw them back, turning them into energy as they go in. For a Pokemon that does not belong to your Pokeball, you must actually *hit* the Pokemon with the ball by throwing it. When the ball hits the Pokemon, its button automatically opens, and sucks the Pokemon in.
However, Pokemon that are too powerful can somehow open the ball from inside it, and escape. When a ball closes around a Pokemon for the first time, the ball will shake and jump around as the Pokemon inside tries to escape. The button glows red, but pings to its normal white colour when the Pokemon has been successfully caught. Otherwise, the ball could be jolted open for the Pokemon to make a break for freedom.
Still, each time they escape a Pokeball, they are weakened a little. In the game, a Pokeball breaks when a Pokemon escapes from it, meaning you have wasted a ball. In the show, it just opens and the Pokemon runs away.
To send a captured Pokemon out, the trainer must throw the Pokeball (Pokeballs can also occasionally be thrown without opening), and its button will open in mid-air. Strangely enough, no matter how far the ball is thrown, it never seems to get lost (even if the trainer is on a small boat or something), and the Pokemon always appears in the exact appropriate place, usually a lot closer than the ball was thrown to.
We all know the real reason for trainers having to throw their Pokeballs out is so they can look cool and dramatic, delivering fancy poses and shouting "go, so-and-so!" or "so-and-so, I choose you!"
Pokeballs do not have to be thrown for Pokemon to return. The trainer presses the button on the Pokeball which shoots out the red energy beam. If the beam touches the Pokemon, they will be drawn back inside; however, this has flaws, such as if the Pokemon is moving fast and the beam won't hit them. Sometimes Pokemon don't want to return to their balls, and thus evade the beams deliberately.
This red beam will not capture Pokemon that do not belong to the ball; the ball has to be thrown for that.
All trained Pokemon must belong to a Pokeball. The reason for this is unknown, as a Pokemon belonging to a Pokeball can still be caught by another. Ash caught a Charmander that was already owned by someone else. Jessie once threw a Pokeball at a Doduo belonging to another Pokeball, and would have caught it were the ball not diverted in mid-air.
Even Pikachu has a Pokeball. Ash occasionally tries to make it go inside, for its own safety, but Pikachu inevitably refuses. Some types of Pokemon just hate Pokeballs - it is not really known why Pikachu hates being inside one so much, but you can't really blame it...
Inside a Pokeball, the red energy that absorbed the Pokemon and drew it inside, is converted back to a miniature version of the Pokemon. This was proven when Psyduck was shown inside its Pokeball; it was a small version of itself that took up most of the space inside the ball.
In that case, being inside a Pokeball must be pretty boring. I imagine the Pokemon within just sleep most of the time, as there would be little else to do. Professor Oak keeps a lot of Pokeballs for people, but he lets all the Pokemon out of their balls for a time, as Pokemon do need to be allowed outside as well.
Pokemon can rest and recover health inside their Pokeballs. (In case you had not realised, this page is mostly relating to Pokeballs in the show, unless otherwise stated.) They have a more stable condition inside the Pokeball than out in the environment, where it may be too cold, or there may be danger, etcetera. As long as they are in their Pokeballs, they do not need to eat. However, after being out, they will need to.
(For example, Bulbasaur could be left inside its Pokeball for weeks and not need any food. But if it came out to fight a battle, the time spent in the real world would lead it to work up an appetite, and it may need to eat.)
Pokemon inside their Pokeballs can hear or sense what is going on outside. On some occasions, they can actually refuse to leave their Pokeballs even when the ball is thrown, or can escape the ball when their trainer has not called for them. Misty's Psyduck can hear when Misty is about to use a Pokemon, and jumps out of its Pokeball - personally, I think Psyduck's Pokeball must have a faulty capture mechanism - regularly to fight instead.
Almost all of the Pokeballs on the show are normal red-and-white cheap Pokeballs. Professor Oak engraved the names of Pokemon on his Pokeballs, as he had a lot, but most trainers do not bother. A Meowth owner had a Pokeball studded with diamonds for her precious pet. Richie stuck little stars on his Pokeballs so that he could tell them apart from those of other trainers. I wonder what happens to the stickers when the Pokeballs shrink...?
Also Ash never labels his Pokeballs, he seems to instinctively be able to tell which ball is which Pokemon. In one episode, he was rifling through a number of trainers' Pokeballs to try to find his own Pokemon. Pikachu sniffed one Pokeball and found it to be familiar, identifying one of Ash's Pokemon without it being out of its ball. Pokemon do still retain their smell inside a Pokeball; Muk, for example, is a terrible Pokemon to carry around, as it smells bad all the time.
Very rarely has anyone chosen the wrong Pokeball. Misty threw an empty Pokeball for battle once, after not using her Pokemon for quite a long time.
Some Pokeballs are given other decoration. A man who conned people into buying worthless Magikarp, had fake gold Pokeballs to make them look more valuable.
Pokeballs can be transported from one place to another, using special transporter machines. Professor Oak can transport Pokeballs to video phones, so that Ash can get the Pokemon he wants. As a trainer can only hold six Pokemon at a time, any additional Pokemon caught will automatically be transported to wherever the trainer got their Pokedex. So, if Ash catches a new Pokemon, the Pokeball disappears in mid-air!
Pokemon Centers can heal Pokemon in their Pokeballs just by putting them into a recharger (I think). This does not work for serious cases. Pokeballs are great for carrying large Pokemon around; they can be used to take a wild injured Pokemon to a Pokemon Center, for example. Pokemon Centers keep a great deal of Pokeballs with sick/recovering Pokemon, and they occasionally transport them from one Center to another, particularly in emergency cases.
Professor Ivy discovered a mysterious Pokeball that did not meet the usual attributes. It looked similar, but was gold-and-silver instead of red-and-white. It had "GS" engraved on it, and was called a GS (Gold Silver) Ball. This ball would not open no matter what, and it could not be teleported. Ash and his friends offered to take this ball to Professor Oak, so that he could try to solve its mystery. Ash got sidetracked on a long training journey, but kept the ball safe, occasionally wondering what it was and if there was anything inside it...
There are seven types of Pokeball.
We have not seen Great, Ultra or Masterballs on the show thus far.
In the video game, Pokeballs are a little different. As mentioned before, they do differ in that if a Pokemon escapes from them, you lose that Pokeball forever. Pokeballs cost money in the game, and as one progresses through their journey, they come to towns that sell the stronger, more reliable types of Pokeball.
Pokeballs cost 200 each, and can be sold for 100.
Greatballs cost 600 each, and can be sold for 300.
Ultraballs cost 1200 each, and can be sold for 600.
Each ball is supposedly stronger than the last. In practise, you are just as well off buying and throwing six Pokeballs than one Ultraball, and more likely to get lucky... unless your Pokemon are weak and likely to be KO'd while you throw, that is.
Silph Company are designing and manufacturing something called the Masterball. These are exclusive to them and guarantee capture... Ash can only get one of them, and the Silph president gives it to him after he saves the company from Team Rocket.
In the game, Pokemon instantly become obedient after being captured. No matter how many badges you have, and how high their level is, they will obey you if you have captured them yourself. Traded Pokemon will give you no such respect.
The symbol for a Pokeball is also used for other items in the game; Pokeballs lie on the ground in a number of places, and picking them up could get you anything from Rare Candy to a fossil, from a TM to a Pokeball. And in the Power Plant, there are Pokemon that strongly resemble Pokeballs; Voltorb and Electrode.
Pokeballs are used as symbols or logos of Pokemon quite often. There is a large Pokeball emblem in Pokemon League; even in ancient times this was the case. In Super Smash Bros., they are wildcards; throwing a Pokeball will draw out a random Pokemon that can attack your enemies in some way. Pokeballs are also the balls in Pokemon Pinball.
Most trainers keep their Pokeballs attached to their belt. Misty keeps hers in her bag, because she does not use them often. Others keep them in their pockets, as their name origin suggests.
Pokeballs are a very convenient capture method, making training a whole lot easier. However, it is not very fair to the Pokemon; ripping them from the wild to suck them into a tiny little ball where they can't move and leave them there for half their lives. Still, it seems to be the way of things, and the key for a Pokemon Master to reach that position...
