Orbit of the Moon. The Moon orbits Earth in the prograde direction and completes one revolution relative to the stars in approximately 27.323 days (a sidereal month). Earth and the Moon orbit about their barycentre (common center of mass), which lies about 4,600 km (2,900 mi) from Earth's center (about 34 of the radius of Earth). On average, the Moon is at a distance of about 385,000 km (239,000 mi) from Earth's centre, which corresponds to about 60 Earth radii.
The Method of Loci is an effective mnemonic device, or a trick to aid in memory storage and retrieval. The effectiveness of the Method of Loci relies on visualizing mental images to associate with the material that needs to be remembered. The more vivid the visual, the more effective the method.
6.1 Conditioning and deconditioning. In psychology, conditioning means learning stimulus-reaction patterns: the body reacts in a certain way to a certain stimulus. Two types of conditioning are distinguished: The classic form of learning via conditioning was described by I. Pavlov.