On this page we take a look at the science behind online slots and how it all works. The entire process is simple for a player, but there is a huge amount of science involved in creating the entire experience: right from the way a slot looks and feels to the way you are guaranteed a completely random outcome for every spin with the random number generator (RNG) and, even further, the psychological aspect that makes slots so successful. You win if you hit a winning combination. The reels spin away and stop at a point in time. You place your bets and hit the Spin button. Online slots are fun to play and are among the most popular games at online casinos.