Notes on Tides

The increase, as well as a decrease in sea levels, is known as tides. It mainly occurs due to the gravitational forces of the moon, sun, and the earth. The tidal force of the moon is larger than the sun. It is because the moon is closer to earth which leads to more gravitational pull. There are different types of it , such as spring tides, neap tides, high tides, and low tides. However, both the high and low tides are caused by the moon. It causes the seawater and the earth to bulge towards the moon. 

What is a Tidal force? 

The tidal force is a gravitational pull by a celestial body such as the moon or sun. It raises the tidal waves towards its gravitational field. It also depends on the distance between the earth and the celestial body. 

What causes tides?

The tide is a term for the increase and lowering of sea levels. The tides are the result of the gravitational force of the moon, sun, and the earth. As the moon is much closer to earth, the tidal force of the moon is stronger than the sun. Thus, the tidal force causes sea levels to rise.

These are the following reasons to understand what are its causes. 

• Tides mostly occur due to the gravitational pull of the moon and the sun. But, the effect of the moon’s gravitational pull is higher than the sun. 
• The centrifugal force is also a major reason that causes tides. 
• It can also occur due to the balance among these different types of forces. 

What are the different types of tides? 

When the wave rises, its highest part is called the crest. When high tides occur, it reaches a specific location. Also, the low tide is related to the lower part of the wave. There different types of tides are based on different types. 

Different types of tidal waves on the basis of frequency

These are the different types of tides listed below. 

Semi-diurnal tide

It is one of the common frequencies of type. In this, two low and high tides occur each day. Also, the size of the high and low tides is almost the same height. 

• This tide occurs at an interval of 12 hours 15 minutes which means twice a day. 
• This tide occurs as the moon revolves from the direction of the west to the east. 
• In Southampton, the tides occur around 6-8 times in a day. 

Mixed tide 

In Mixed tides, the height of the low and high tides vary. Hence, these types of tides mainly occur in the west coast region of North America. 

Diurnal tide

In the diurnal tide type, only one low and high tide occurs in a day. Also, the low and high tides are considered to be of the same height. 

Different types of tidal waves on the basis of earth, sun, and moon positions

The high tides vary depending on the positions of the moon and the sun. These two tides are called the neap tides and spring tides. 

Spring Tides

These are the following characteristics of spring tides. 

• It happens when the moon, earth, and the sun are in a straight line which is also called syzygy. 
• This causes the height of the tide to increase. 
• The spring tides mainly occur during the period of the full moon and new moon. 
• Spring tides occur twice a month. 

Neap Tides

These are some important characteristics of neap tides. 

• The neap tides occur when the moon is at the stage of the first or third quarter. In this position, the moon and the sun are divided by an angle of 90 degrees from the earth. That’s why the tidal forces of the sun affect the moon.
• The gravitational pull by the moon lessens due to the force exerted by the sun’s gravity. Due to this, the tide range goes down to a minimum which is known as neap tides. 

Hence, the neap tides occur two times in a month. Generally, there is a gap of seven days between the occurrence of neap and spring tides.

Conclusion

In conclusion, the tides occur due to the gravitational pull exerted by the moon as well as the sun. These cause the sea waves to rise when the moon or the sun comes closer to the earth. The gravitational pull of the moon is larger as compared to the sun due to its distance. That’s why high tides generally occur during the period of the full moon and new moon. The tides are divided based on the frequency and the position of the moon and sun.