Slot games were made to keep waiting wives busy while their husbands whiled away their time and money on the real casino games such as poker and blackjack, but a century onwards they have become one of the biggest money spinners for the casinos worldwide and a popular choice for players.
The earlier machines had spinning wheels with different numbers or symbols imprinted on them, but they have now made way for computerized Slot machines with a random number generator. Here is a little overview.

Welcome to the machine
The earlier machines usually had three wheels, each imprinted with ten or twelve symbols. The machines used nowadays have a random number generator (RNG) that fishes out a number as soon as you pull the lever; these generated numbers decide the outcome of the bet. Other than the aesthetic advantage for the player, these machines offer much higher odds as the number of possible outcomes has increased by manifolds. These can be broadly classified into straight slot machines and progressive slot machines.
In a straight slot machine the jackpot is constant at its default value while the progressive slot machines are more enticing to a player by the virtue that the jackpot goes on accumulating as more and more coins are played in the machine. An online slot machine is a graphical reproduction of these machines and work on the same RNG principle. The machine is similar in all respects other than the physical contact, including the lights and the music. A slot machine may have three, four or five reels with increasing odds.

The winning odds
The odds on a slot machine vary with the value they use to generate RNG series. For a machine with such a value as sixty four, the chance for a person to strike a jackpot becomes one in 262144. However strict regulatory laws world over ensure a payback percentage of around 95%, that means, that at an average for every dollar put in to the machine, it gives out 95 cents as winnings. The computer chip in the slot machine cannot be replaced or tampered by the casino thus making it cheat free.

Myths
These might be the production of a loose gambler who had had a little too much to drink, or they might be rumors started by casinos themselves to generate interest, whatever be the source, it would not help to warm a coin in your palms before putting it into the slot, nor is one machine more likely to strike you a jackpot than the one beside it. Since all bets depend upon the numbers generated in RNG, a machine about to hit a jackpot is impossible to predict.