2.2.4 Moon's Pull and Tides

The extra pull of the tides is dragging the moon away from the Earth. Similar to if you are sitting on a "roundabout"-- the faster it spins, the more you feel slung outward.

More info: Due to the rotation of the Earth, this tidal bulge actually sits slightly ahead of the Moon. Some of the energy of the spinning Earth gets transferred to the tidal bulge via friction.

This drives the bulge forward, keeping it ahead of the Moon. The tidal bulge feeds a small amount of energy into the Moon, pushing it into a higher orbit like the faster, outside lanes of a test track.

Moon is getting farther away

April 1
High tide = 3.9
Low tide = 1.8
Difference = 2.1

April 20
High tide 5.0
Low tide 0.6
Difference = 4.4

Just another view of tides and moon phases.
(From: National Oceanic and Atmospheric Administration)

Earth rotates, so when the moon is in line with the ocean or on the complete opposite, water level is high. Low tide is when moon is at 90 degree angle from that location.

Videos on next two slides.