A dream is a series of thoughts, images, or emotions occurring during sleep. When this happens it's like having an experience of waking life in the characteristics of a dream. There have been many scientific studies on how, and why, people dream. When you dream you go through various stages.
Before the first stage of sleep, a transitional period called hypnagogic occurs. Hypnagogic is when the muscles relax and a person often experiences sensations of floating or drifting. During this time, the sleeper will usually think of many things, such as, what they did that day, or what they needed to do but didn't; a little bit of everything is thought right in that first relaxation point. After these sensations come and go, a thing happens called hypnagogic startle. Hypagogic startle is where your body may twitch and jerk a little; just enough movement to wake you up for a short period of time.
Sleeps first stage is short and lasts anywhere from just a few seconds, to ten minutes. During this time a person awakened from sleep may report having had brief bits of realistic thought, or may even deny being asleep at all. During the next fifteen to thirty minutes a person slowly fades in to and out of stage two. After stage two, comes three and four. Three and four are very similar; waking from three and four is difficult. An individual typically feels quite groggy and disoriented if awakened. Next, a person goes through cycles of REM and non-REM phases. Each cycle takes about ninety minutes to run its course; the average sleeper experiences four to five cycles a night. As the night progresses time in the REM stages increases and non-REM decreases. Consequently, almost half of a person's nightly dreaming often takes place during...