In the old days, record-pressing companies used audio tape to cut grooves on a flat disc using burning-hot heating wire to cut the grooves and create the "lacquer" (now they use audio files burned to CD). After creating the lacquer, they spray it with silver, and once the silver's peeled off, the disc is a "master." It can't actually be played yet, however--it has ridges instead of grooves. The master is then pressed into a metal disc, "the mother," which can be played, and the mother is pressed into a stamper, which is used to press the vinyl.
Raw vinyl looks like Pop Rock candy--it's brittle and in millions of tiny hunks, and it comes in many different colors. Sometimes, manufacturers mix colors together in the stamping process to create a melted color effect. The vinyl, melted into a small shape which makes up the small center, is called a "biscuit." The biscuit is where the center of the record will be, and also where the label is affixed. Fresh vinyl will be stamped with the audio track around the biscuit to create the rest of the album.
Labels are produced by the thousands and then baked in a special oven to prevent bubbling. There is no adhesive necessary because the vinyl is hot when the label is affixed. The biscuit is placed in the middle of a machine, joined together with a fresh supply of vinyl, and smashed between a plate and the stamper. A blade then shears off the excess vinyl, and a brand-new record slides out of the machine and onto a rack. Workers manually put discs in their jackets and sleeves.
Records are carved in one continuous groove. The stylus--the needle--responds to the pickups in the record to create sound. A "single," usually several minutes long, is seven inches in diameter. An "LP" or "long-playing" album usually lasts for 20 to 30 minutes and is 12 inches in diameter.
Vinyl records are easily scratched, and any type of dust between the grooves can cause "pops" and "clicks" during playback. Record players themselves add small changes, such as "wow" (variation in rotational speed due to changes in the belt drive tension), "flutter" (faster variations due to motor irregularities), and "rumble" (vibrations from the motor being transferred to the pickup). The stylus could also "jump" from one groove to another if the record player was bumped (or even if someone jumped on the floor nearby), and a damaged groove could cause the record player to "skip," playing the same groove over and over again.