Free Worksheets, Lessons, Quizzes
Free Worksheets, Lessons, Quizzes
In this lesson you can learn a lot of facts about tides and ocean currents.
The rise and fall of the level of the oceans and seas twice a day are tides. Tides can move the seawater from place to place.
The gravitational attraction of the moon and the sun upon the water and upon the earth itself causes tides.
1) Ordinary tide
2) Spring tide
a) High tide
b) Low tide
High tide and low tide are ordinary tides.
High Tide
Twice each day, the level of the ocean or sea rises and water covers the shore. Then we say that the tide is ‘in’. This is called ‘high tide’.
High tide brings deep water to harbours and ports so that the ships can sail in and out.
High tide may cause flooding.
Low Tide
Twice each day, the level of seawater falls. The seashore is uncovered. Then we say the tide has ‘gone out’. This is called ‘low tide’.
Ordinary tides are caused by the combined pull of gravity of the Sun, and of the Moon as it circles the Earth.
These tides occur twice a month.
When the Sun and Moon are both on the same side of the Earth these tides are occurred. The pull of both the Sun and Moon makes the water pile up higher than usual.
Waves are big ripples of water caused by the wind. Waves make the water move up, down and around. Waves do not move the seawater from place to place. Huge waves can batter down rocks, wear away cliffs and lift big pieces of rock.
This is a powerful movement of water that has a steady flow in one direction. Ocean currents can move the seawater from place to place.
1) Warm Currents
2) Cold Currents
Currents coming from colder regions in the ocean to warmer regions in the ocean are called warm currents.
Examples of warm currents
Currents coming from warmer regions in the ocean to colder regions in the ocean are called cold currents.
Examples of cold currents
Ocean currents help to distribute heat around the Earth and have a great influence on climate.
We hope you learned important facts about tides and ocean currents.
Also, read the lessons Coasts and coastal Landforms.