Children who live by the beach know that the sea rises and falls twice a day. Why does the sea change in this way? This is the result of the Moon's attraction to seawater.
The Earth has gravity, and we all understand that. No matter how high we jump, we end up falling back to the ground because Earth's gravity has pulled people back. There is gravitational pull between any two objects, and the Moon also has a great attraction force to Earth. Thus, the moon is attracted to the sea water on the side of the moon; And the sea water carrying one end of the moon is far away from the moon, and the gravitational pull of the moon is less, so it will bulge, which is the high tide. The lowering of the sea elsewhere is the low tide. The Moon circles the Earth once a day, and anywhere on Earth there is a chance to face and carry the Moon on its back, so most days there are two high tides and two low tides.
The sun also has a certain influence on the high tide and the low tide, every first and fifteenth is the new moon and the full moon, the sun, the earth, the moon are arranged in a straight line, the gravitational pull of the sun and the moon adds together, so there will be a big tide. When the Sun, the Moon and the Earth are arranged at a 90-degree angle, that is, part of the gravitational pull of the upper and lower chord moons, so there will be small tides.
