The Tides
The Tides are the rise and fall of sea levels experienced on coastlines at different parts of the earth. Tides occur on the oceans and inland seas, while lakes and rivers often do not experience tidal effects. Despite the popular explanation of the cause of tides being due to gravity of the moon and sun, the cause of the tides remains an unsolved issue in science. Issac Newton is said to have considered the tides to be the least satisfactory part of his theory of gravitation1.
Tidal Nodes Analysis
YouTube user Strange Maps presents a series of videos which analyzes the Tidal Nodes, showcasing the unsatisfactory explanation of the tides as being due to the gravitational influence of the moon.
References
1 Rowbotham, Samuel Birley. "Chapter XII." Earth Not a Globe., Second Ed., p.160.