Reels are the old term used for the original slot machines. The original machines made from metal had round drums with symbols painted upon them. The intricate clockwork of gears and springs allowed the reel to spin when the lever was pulled. The reel spun on its own gravity (to some extent) until it stopped. The result was a combination that could be shown over the 3 reels that many of the old machines held within. There are many symbols that are painted onto the reels forming a number of combinations that will make a win possible.
The reels in new video slots don’t spin at all, however. Actually they are created through a random program which allows the game to simulate the old version of the classic slot machine. The symbols on the electronic reels can change to whatever is programmed into the game. Any number of chances will result in a new reel spin.
Many new slot games have a typical number of 5 reels across the screen. There are usually 15 symbols that can be seen on the screen from the view of the player. Older versions have 3 reels and 9 symbols showing.
Since the reels work in combination with paylines, the chances to get a combination that secures a win are higher. The lower amount of reels means the odds are usually better but not always. It all depends on the number of symbols that are shown in the game as well. Chances to win are about the same when playing with table games such as roulette or keno. The number of choices will allow the odds to be better when choosing the numbers that are picked.