Tides - are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.
Most places in the ocean usually experience two high tides and two low tides each day (semidiurnal tide), but some locations experience only one high and one low tide each day (diurnal tide)
Two types of tides
Spring Tides
By definition, spring tides are the horizontal flow of water toward two regions of the Earth representing positions of maximum attraction of the combined solar gravity and lunar gravity. Twice a month, the three planets, the Earth, the Moon, and the Sun line up in a straight line, once the Moon is between the Earth and the Sun ( new phase of Moon ), and once the Earth is between the Moon and the Sun ( full phase of Moon ).
Neap Tides
Neap tides are made up of a compensating pull of water from regions around the midway of the Earth. Conversely, neap tides occur when the Moon is at first quarter phase or last quarter phase. During these periods, the Moon and the Sun are at right angles to each other, the solar gravity and the lunar gravity interfere with each other. Consequently, the competition of these two gravitational forces tend to reduce the distortion that apply upon the Earth.
Earth - Big ball of iron with some rock on the outside and a very very thin coating of moisture and oxygen and dangerous creatures.
Sun - G2-type main sequence star that has been shining for almost 5 billion years. It is known from radioactive dating of the Earth, Moon, and meteorites, that these objects have been around for about that length of time and temperatures on the surface of the Earth have been pleasant since it formed.
Moon - The moon is Earth's only natural satellite. The moon is a cold, dry orb whose surface is studded with craters and strewn with rocks and dust (called regolith). The moon has no atmosphere. Recent lunar missions