Tides are a natural phenomenon that occurs in the seas and oceans, and they are defined as the periodic and regular rise and fall of sea water levels. But how does this phenomenon occur? And what is the timing of its occurrence? Before we delve into the explanation of this phenomenon, it is worthwhile to briefly address two types of forces in our universe in order to make it easier for anyone looking for a scientific explanation for this phenomenon to understand.
Gravity is a force that arises between objects that works to pull them and attract them to each other. And it decreases as the distance that separates them increases, and if we take the earth and the moon as an example, we will find that there is a force that attracts between these two bodies, and the same is true between the sun and the moon. The same is true for any other two bodies, no matter how large or small their masses are.
It is a force that arises when objects move in a circular or curved way, as it works to push objects away from the center of rotation, and one of the simplest examples of it is the force that we feel when we are in vehicles when they pass on a circular or curved road, where we feel a force that pushes us outside the path of rotation or curvature .
Interpretation of the tides
The tides are caused by the influence of two forces:
- The force of gravity: It is divided into two parts, the force of gravity between the earth and the moon, and the force of gravity between the earth and the sun. The distance plays a big role in this case. As for the gravity that occurs between the Earth and the sun, it is considered a contributing factor to increasing or weakening the tidal force, as follows. The gravity of the moon affects the surface of the Earth and thus affects the surface of the water when it is close to these flats. The water level, which leads to a rise in the water level, the phenomenon of tides occurs, and the opposite when the moon moves away from these bodies of water, and the force affecting the surface of the water disappears, which leads to a decrease in its level, and the phenomenon of islands occurs. As for the force of attraction of the sun, it works as follows. Weakening the force of attraction of the moon to the earth, which leads to a weakening of the tides, and thus the sun is considered a factor regulating the force of the tides, where the tides are at their strongest when the sun, the earth and the moon are on a straight line, and the tides are at their weakest when the three bodies form a right triangle The angle, i.e. the sun and moon are on either side of a right angle, the earth is its center. It is also known that the tides are at their greatest when the moon is full or new.
- Centrifugal force, it is known that the earth revolves around itself and the sun at the same time, which leads to the generation of centrifugal forces that affect the water level on the surface of the earth, and the phenomenon of tides occurs twice a day for the same water surface, according to the division of the lunar day, which Its duration is approximately 24 hours and 50 minutes, where the first tide occurs for about 6 hours and 12 minutes, then it is followed by the tides for the same period, then the tides return to the ball again, to complete the cycle of the lunar day.
The strength of the tides varies from one region to another on the surface of the Earth. It is normal for the tides to rise or fall only a few centimeters in one area, and meters in another. For example, the tidal height in the Bay of Fundy region in Canada reaches More than 15 meters, while not exceeding 40 centimeters in the Mediterranean.
When do the tides happen?