What is Water?: Sea Waves, Tides, Ocean Waves and Solved Examples

The compilation of these Water Notes makes students exam preparation simpler and organised.

What is Water?

What is Water? Can you imagine surviving without water? No, right? It is impossible to live without water. It is the most basic necessity of all living creatures. No living creature can survive without it. Earth is the only planet that has water in it. Let’s find out more about it.

Sea Waves

The up and down movements of water in the sea are known as sea waves. The lower part is called wave trough whereas, the upper part of the wave is called wave crest. The distance between two adjacent crests is the wavelength and the vertical distance between the crest and the trough is the wave height.

Sea Waves


Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of Earth. The rise of water level in the sea indicates high tide and lower water level indicates low tide. The types of tides are spring tides and neap tides.


Ocean Tides

The continuous flow of seawater from one direction to another is called ocean tides, It is caused by forces acting upon this mean flow, such as breaking waves, wind, the Coriolis effect, cabbeling, temperature, and salinity differences. They are classified as warm currents and cold currents.

Ocean Tides

Warm currents are currents that come from tropical or subtropical regions and flow towards the polar or subpolar regions. The water is warm here hence it is called warm currents. Similarly, cold currents are the currents that flow in from the polar or subpolar regions towards the tropical or subtropical regions. The water is cold here hence it is called cold currents.


Question 1.
Which of the following is a type of wave?
a. Ripples
b. Swells
c. Sea
d. All are the types of waves
The correct answer is the option “d”.
Ripples are the instant effect of wind on the water and they die down as quickly as they form, as the surface tension of the water dampens their efforts. Waves always travel in the same direction as the wind is blowing: if the wind changes then the waves change with it.

Wave size is determined by the strength of the wind, the length of time it has been blowing and the distance it has blown over or the ‘fetch’. When strong winds blow for longer than a few hours, it gives the water sufficient energy that it then takes on a character of its own. This character and movement are known as a swell, and it will march across open areas of water independent of the wind.

Question 2.
Which factors influence ocean currents?
a. Earth’s rotation
b. Winds across ocean
c. The density of water
d. All of the above
The correct answer is the option “d”.

Factors Influencing Nature and Movement of Ocean Currents are:

  • The earth’s rotation: Gravitational force and force of deflection.
  • The sea: Atmospheric pressure, winds, precipitation, evaporation, and insolation. It also includes pressure gradient, temperature difference, salinity, density, and melting of ice.
  • Modified ocean currents: Direction and shape of the coast, seasonal variations, and bottom topography.