One of the most characteristic features of the sea is the tides. If you plan to take sailing trips, knowing well what the tides are will help you enjoy sailing more and also sail more safely.
Tides are periodic changes that occur in sea level due to the forces of gravitational attraction between the Sun and the Moon. Surely you have read many times that our moon has a great influence on the sea and so it is due to the tides.
The gravitational attraction between these two stars causes the movement of enormous masses of water across the surface of the earth, so it is common for these changes in level to occur.
What are the tides due to?
The main reason for tides is due to the force of gravity. Although Newton’s law of gravitational attraction says that the force of attraction will depend on the mass of the bodies, it also depends on the distance that separates them. Although the sun has much more mass than the moon, the moon is much closer, so its attraction rate is higher.
This proximity of the earth to the moon unlike the sun causes the lunar tides, that is, the tides that are caused by the force of attraction of the moon, to be more important in amplitude compared to those that can be caused by the sun. Although this may seem quite simple, it is important to note that there are many different types of tides as we are going to see.
The Moon and the Tides
Although the main reason for the tides is the force of attraction of the moon, the truth is that it is more complex than it seems. It is enough to take a look at the sky and check the state in which the moon is to better understand what type of tide occurs.
In addition to the force of attraction of the moon, the position of the stars must also be taken into account, not only between the moon and the earth, but also the position of the moon in relation to the sun.
Although we have pointed out that the sun has a lesser influence on the tides, its combined effect with the moon gives rise to different tides that can occur throughout the year. It is also important to note that in addition to the moon, there are also other factors that can affect the tides.
These factors have to do with the shape of the coasts, their depth or certain meteorological phenomena that can affect the tides. The sum of all these conditions will cause the sea to be in one state or another.
Types of tides
There are several types of tides. Whether these tides form will depend on the conditions mentioned above and, in order to analyse the type of tide in question, different aspects will be taken into account. We are going to see the types of tides that exist and better explain what are the criteria that are followed to be able to classify a certain tide of a certain type.
Low tides and high tides
Tides, low tides and high tides are classified depending on the height that the sea water reaches. When it comes to high tide, also called high tide, it occurs when the height of the sea reaches its highest level. This type of tides occurs approximately every 12 hours.
On the other hand, low tide, also known as low tide, is called when the opposite effect occurs, that is, the water level reaches its minimum. This type of tides also occurs every 12 hours.
As you can see, due to its repetition cycle of every 12 hours, this type of tides follow one another alternating in an interval of 6 hours. In the same way, while in one part of the globe we have a high tide, in the opposite part we will have a low tide.
Spring and dead tides
Another type of classification that exists for tides depends on the phase in which the moon is, for example, when it is in a full moon, new moon, last quarter or first quarter. Depending on the phase in which it is, we can find spring tides or dead tides.
- What are spring tides?
Spring tides occur when the moon is in the full moon and new moon phase. In these phases the sun and moon are aligned and, therefore, the gravitational effect that is achieved is greater. Thanks to this superior gravitational effect compared to other positions, the amplitude in these tides is much greater than others. - What are dead tides
On the other hand, we have the dead tides that occur when the moon is in the last quarter and first quarter phase. The position of the stars in these phases is that they are at antagonistic points, that is, forming an angle of 90º to each other.
This position implies that the forces of attraction of both are compensated, which translates into tides of lower amplitude.
How to know if the tide is rising or low
Due to the importance of the water being at its highest point or, on the contrary, going down, it is very important to know if the tide is going to rise or fall. To know if the tide is rising or falling, you have to take into account the periodicity we mentioned before and, in addition, you can also help yourself by observing the phase in which the moon is.
Another aspect that allows us to help us determine if the tide is rising or falling are the remains of foam or other debris that may appear. If there is a lot of debris, it means that the tide is going out.
Finally, if you have a device with internet at hand, a simple search on the web will help you know the state of the tide. It is enough to know in the region in which you are and look up the state of the tide on the internet, in fact, this is the safest way to answer this question as long as you are clear about where you are.
