Dreams are what a person sees and hears in their mind when they are sleeping. They are often similar to real life in some ways but can also be very strange. Dreams can feel so real that the person dreaming may not believe they are awake. This tends to happen during a false awakening, where a person dreams of waking up. A person has around 4 - 6 dreams per night and tends to only remember the last two.
Sometimes, a person realizes during a dream that they are dreaming but keeps having the dream. This is called lucid dream. This rarely happens for most people. During a lucid dream, a person usually has full control over their body as well as the environment around them. There are no limits in lucid dreams, sometimes not even the imagination.
Most people remember their dreams in some way or another, even if it is only a small part, but children are more likely to remember most of their dream clearly. It is often easier for people to remember dreams if they write down what happened in the dream just after they wake up. Because of this, many people have dream diaries where they describe each dream they have. This is called dream recall. The more it is done, the better they remember their dreams. If a person is woken up during a dream, they tend to have a much more reliable memory of it.
Nightmares are dreams which scare or shock people. Nightmares are usually based around a person's everyday fears, like spiders or dark places, but even a dream that's not about those things can feel unpleasant. Nightmares are caused by many different things: being uncomfortable or in pain while sleeping, sickness, stress, or even eating right before sleeping.
There are many different theories about why people dream and what their dreams mean. Every person has different dreams. Some psychologists believe that dreams reflect what is happening in the unconscious mind (the part of the mind that works by itself). Others think that people, places, and objects in dreams are symbols for other things in the dreamer's real life. Throughout history, people have tried to make sense of dreams to learn things from them and have often used them for divination or fortune-telling. Today, there are still many books and websites devoted to making sense of dreams.