NCERT Class 11 Geography Fundamental of Physical Geography: Chapter 13 — C H A P T E R
This chapter, 'Movements of Ocean Water,' from NCERT's Fundamental of Physical Geography for Class 11, explores the dynamic nature of ocean water. It details the horizontal and vertical motions, including ocean currents, waves, and tides. Waves are explained as energy transfer caused by wind, with their characteristics like height, wavelength, and speed defined. Tides are described as the periodical rise and fall of sea levels, primarily driven by the gravitational pull of the moon and sun, and centrifugal force. The chapter also touches upon how factors like continental shelves, bays, and estuaries influence tidal magnitudes. Understanding these movements is crucial for comprehending oceanic processes and their impact on coastal environments, aiding CBSE students in their geography studies.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 11 |
| Subject | Geography |
| Book | Fundamental of Physical Geography |
| Chapter | Chapter 13 — C H A P T E R |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 6 minutes |
| Word count | 1009 |
Learning outcomes
- Differentiate between horizontal and vertical movements of ocean water.
- Explain the formation and characteristics of waves.
- Understand the causes and types of tides.
- Recognize the factors influencing tidal magnitudes.
Vocabulary
| Word | Meaning |
|---|---|
| Ocean currents | Continuous flow of huge amount of water in a definite direction. |
| Waves | Horizontal motion of water, transferring energy across the ocean surface. |
| Tides | Periodical rise and fall of the sea level, mainly due to the attraction of the sun and the moon. |
| Crest | The highest point of a wave. |
| Trough | The lowest point of a wave. |
| Wave height | The vertical distance from the bottom of a trough to the top of a crest. |
| Wavelength | The horizontal distance between two successive crests. |
| Centrifugal force | A force that acts to counter balance gravity, responsible for tidal bulges. |
| Surges | Movement of water caused by meteorological effects like winds and atmospheric pressure changes. |
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Practice questions
- What are the two main types of ocean water movements? Answer: Horizontal motion (ocean currents and waves) and vertical motion (tides).
- What causes most of the waves in the ocean? Answer: Most waves are caused by the wind driving against the water.
- Define tides. Answer: Tides are the periodical rise and fall of the sea level, once or twice a day, mainly due to the attraction of the sun and the moon.
- What are the two main forces responsible for creating tidal bulges? Answer: The gravitational pull of the moon and the centrifugal force.
Practice MCQs
Q1. Which of the following is a horizontal motion of ocean water?
Explanation: Ocean currents are a continuous flow of water in a definite direction, representing horizontal movement.
Q2. What is the highest point of a wave called?
Explanation: The crest is defined as the highest point of a wave.
Q3. The periodical rise and fall of sea level is known as:
Explanation: Tides are specifically defined as the periodical rise and fall of the sea level.
Q4. Which celestial body's gravitational pull is the primary cause of tides?
Explanation: The moon's gravitational pull is the major cause for the occurrence of tides, with the sun playing a lesser role.
Q5. What force acts to counterbalance gravity in the formation of tidal bulges?
Explanation: Centrifugal force is described as the force that acts to counter balance gravity in the context of tidal bulges.
Frequently asked questions
What are the primary movements of ocean water discussed in this chapter?
The chapter discusses horizontal movements like ocean currents and waves, and vertical movements like tides.
How are waves formed?
Most waves are formed when wind drives against the water, transferring energy.
What is the difference between waves and ocean currents?
Ocean currents involve the continuous flow of water from one place to another, while waves are primarily the movement of energy across the surface, with water particles moving in a circular path.
What causes tides?
Tides are primarily caused by the gravitational attraction of the moon and, to a lesser extent, the sun, along with centrifugal force.
What is a tidal bulge?
A tidal bulge is an outward swelling of ocean water caused by the differential gravitational pull of the moon and the centrifugal force on opposite sides of the Earth.
Do factors other than the sun and moon affect tides?
Yes, the shape of continental shelves, bays, estuaries, and coastlines can significantly influence the magnitude and intensity of tides.
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NCERT Class 11 Geography — Fundamental of Physical Geography — Chapter 13 — C H A P T E R. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.