The EEG records electrical activity in the brain from the scalp using electrodes placed according to the 10-20 system. There are different types of brain waves seen on EEG including alpha, beta, theta, and delta waves which vary in frequency and amplitude. Factors like age, consciousness, medications, and stimuli can influence the brain waves observed on EEG. Hans Berger first recorded human EEG waves in 1929, establishing EEG as a tool for examining brain function.