CSS Notes General Science & Ability Notes

Waves – Tides & Current | CSS General Science Notes

Waves - Tides & Current | CSS General Science Notes
Written by Shahzad F. Malik

Waves – Tides & Current
CSS General Science Notes


The winds cause waves on the surface of the ocean (and on lakes). The wind transfers some of its energy to the water, through friction between the air molecules and the water molecules. Stronger winds (like storm surges) cause larger waves.


Tides are periodic rises and falls of large bodies of water. Tides are caused by the gravitational interaction between the Earth and the Moon. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Since the earth is rotating while this is happening, two tides occur each day. Isaac Newton was the first person to explain tides scientifically.

The Sun’s Interaction with the Tides

Spring tides are especially strong tides (they do not have anything to do with the season spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.

The Proxigean Spring Tide is a rare, unusually high tide. This very high tide occurs when the moon is both unusually close to the Earth (at its closest perigee, called the proxigee) and in the New Moon phase (when the Moon is between the Sun and the Earth). The proxigean spring tide occurs at most once every 1.5 years.

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Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons.

An Ocean Current

An ocean current is a continuous, directed movement of ocean water generated by the forces acting upon this mean flow. Such as breaking waves, wind, Coriolis effect, cabbeling, temperature and salinity differences and tides caused by the gravitational pull of the Moon and the Sun

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Ocean currents can flow for great distances, and together they create the great flow of the global conveyor belt which plays a dominant part in determining the climate of many of the Earth’s regions. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate than any other region at the same latitude. Another example is Lima, Peru, where the climate is cooler (sub-tropical) than the tropical latitudes in which the area is located, due to the effect of the Humboldt Current.

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About the author

Shahzad F. Malik

Shahzad Faisal Malik is the administrator of CSSTimes.pk and is responsible for managing the content, design, and overall direction of the blog. He has a strong background in Competitive Exams and is passionate and sharing information with others.
Shahzad Faisal Malik has worked as a Graphic Designer/Content Creator at CSSTimes in the past. In his free time, Shahzad Faisal Malik enjoys watching Cricket, writing blogs for different websites and is always on the lookout for new and interesting content to share with the readers of this website.
As the website administrator, Shahzad Faisal Malik is dedicated to providing high-quality content and fostering a welcoming and engaging community for readers. He looks forward to connecting with readers and hearing their thoughts and feedback on the website.

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