The idea of Tabula Rasa is basically defined as a "blank slate." Locke believed that everyone is born with a clean mind, a supposed condition that he attributed to the human mind before ideas have been imprinted on it by the reaction of the senses to the exterior world.
"Thus the first capacity of human intellect is that the mind is fitted to receive the impressions made on it; either through the senses by outward objects; or by its own operations when it reflects on them. This is the first step a man makes towards the discovery of anything..." -John Locke (On Ideas as the Materials of All Our Knowledge)
Locke considers the new mind as white paper or wax. It is to be moulded and formed as one pleases. It is up to the teacher to insure that it is formed the correct way and that there is no inate knowledge. This is incorporated into education the grade system. Children start out in kindergarten or pre-school with a blank slate; we start teaching the very basics as if they know nothing. The more information and experience they gather, the further they move along the grade continuum.
Locke was considered the founder of British empiricist. He believed that all knowledge comes to us through experience. "No man's knowledge here can go beyond his experience." Basically, all knowledge has its origin and end in experience, or perception using the senses. He says, "Experience is twofold, sensation and reflection. From both sources we obtain ideas." Sensation is the perception of external phenomena and reflection is the perception of the operations of the mind itself.
This view of empirical thinking is widely used in schools today, especially in the science fields.