MOVEMENTS OF OCEAN WATER | Class 11 Geography Notes
By ConceptScroll Team · Published on 17 July 2026 · 4 min read
MOVEMENTS OF OCEAN WATER – this guide gives you a concise, exam-ready overview of MOVEMENTS OF OCEAN WATER from Class 11 Geography, written by ConceptScroll editors and reviewed against the latest NCERT textbook.
Characteristics of Waves
Waves have several key characteristics that describe their size, shape, and behavior. The highest point of a wave is called the crest, while the lowest point is the trough. The wave height is the vertical distance from the trough to the crest, and the wave amplitude is half of this height. The wavelength is the horizontal distance between two successive crests. The wave period is the time taken for two successive crests or troughs to pass a fixed point, and wave frequency is the number of waves passing a point per second. Wave speed is the rate at which the wave travels through water, typically measured in knots. These characteristics depend on factors such as wind speed, duration, and the area over which the wind blows. Steep waves are usually young and formed by local winds, while slow, steady waves originate from distant storms or other hemispheres. The interplay between wind forces pushing water and gravity pulling wave crests downward results in the continuous propagation of waves across oceans.
📊 Diagram: Refer to Figure 13.1 showing wave crest, trough, wavelength, and circular motion of water particles beneath the wave.
🔗 Connection: Leads to the study of tides, the vertical movement of ocean water influenced by gravitational forces.
Frequently asked questions
1. Multiple choice questions. (i) Upward and downward movement of ocean water is known as the : (a) tide (c) wave (b) current (d) none of the above (ii) Spring tides are caused : (a) As result of the moon and the sun pulling the earth gravitationally in the same direction. (b) As result of the moon and the sun pulling the earth gravitationally in the opposite direction. (c) Indention in the coast line. (d) None of the above. (iii) The distance between the earth and the moon is minimum when the moon is in : (a) Aphelion (c) Perihelion (b) Perigee (d) Apogee (iv) The earth reaches its perihelion in: (a) October (c) July (b) September (d) January
1.(i) Correct answer: (a) tide Explanation: Upward and downward movement of ocean water is called tide, caused mainly by gravitational pull of moon and sun.
1.(ii) Correct answer: (a) As result of the moon and the sun pulling the earth gravitationally in the same direction. Explanation: Spring tides occur when sun and moon are aligned, their gravitational forces combine causing higher high tides.
1.(iii) Correct answer: (b) Perigee Explanation: Perigee is the point in moon's orbit closest to e
2. Answer the following questions in about 30 words. (i) What are waves? (ii) Where do waves in the ocean get their energy from? (iii) What are tides? (iv) How are tides caused? (v) How are tides related to navigation?
(i) Waves are rhythmic movements of water on the ocean surface caused mainly by wind.
(ii) Waves get their energy from the wind blowing over the surface of the ocean.
(iii) Tides are the regular rise and fall of sea level caused by gravitational forces.
(iv) Tides are caused by the gravitational pull of the moon and the sun on the earth's oceans.
(v) Tides affect navigation by influencing water depth and currents, important for ship movement and docking.
3. Answer the following questions in about 150 words. (i) How do currents affect the temperature? How does it affect the temperature of coastal areas in the N. W. Europe? (ii) What are the causes of currents?
(i) Ocean currents influence the temperature of coastal regions by transporting warm or cold water from one place to another. For example, the Gulf Stream is a warm current that flows from the Gulf of Mexico towards the North Atlantic, warming the coastal areas of Northwestern Europe. This results in milder winters and a more temperate climate compared to other regions at similar latitudes.
(ii) The causes of ocean currents include wind patterns, the rotation of the Earth (Coriolis effect), dif
# Project Work (i) Visit a lake or a pond and observe the movement of waves. Throw a stone and notice how waves are generated. (ii) Take a globe and a map showing the currents of the oceans. Discuss why certain currents are warm or cold and why they deflect in certain places and examine the reasons.
Project Work does not have fixed answers but involves practical observation and discussion.
(i) Observing waves generated by throwing a stone helps understand wave formation and propagation.
(ii) Using a globe and ocean current maps helps analyze factors like Earth's rotation, wind patterns, and temperature differences that cause currents to be warm or cold and their deflection.
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