PC Hardware Components - Memory or RAM

RAM (Random Access Memory) holds all of the "active" information that the computer is using. Memory is empty when your PC is switched off Then each program or data file used grab part of the system memory. When you close a program the memory grabed by that program is freed up. Generally, the more memory your system has, the more things you can do with it simultaneously. Increasing the amount of memory in the system also improves performance in most cases.
Even though it is a Computer hardware component, RAM is also like humen memory. Imagine you are reading a book. When you start reading a book the content of the book remains in your memory. But it goes away when your attention goes to somewhere else.