Why RAM is said to be a volatile memory? Explain it's types.

Volatile memory is computer storage that only maintains its data while the device is powered.,Most ,RAM, (random access memory) used for primary storage in personal computers is volatile memory. RAM is much faster to read from and write to than the other kinds of storage in a computer, such as the ,hard disk, or ,removable media,. However, the data in RAM stays there only while the computer is running; when the computer is shut off, RAM loses its data.,Volatile memory contrasts with ,non-volatile memory,, which does not lose content when power is lost. Non-volatile memory has a continuous source of power and does not need to have its memory content periodically refreshed.