Question 1

Q1: (i) Upward and downward movement of ocean water is known as the : (a) tide (b) current (c) wave (d) none of the above

Accepted Answer

(a) tide The source content states that vertical motion refers to the rise and fall of water in the oceans and seas, and this periodical rise and fall is called a tide. Currents and waves are described as forms of horizontal motion.

Question 2

Q2: (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 moo...

Accepted Answer

(a) As result of the moon and the sun pulling the earth gravitationally in the same direction. According to the text, spring tides occur when the sun, the moon, and the earth are in a straight line. In this alignment, their combined gravitational forces pull in the same line of action, resulting in...

Question 3

Q3: (iii) The distance between the earth and the moon is minimum when the moon is in : (a) Aphelion (b) Perigee (c) Perihelion (d) Apogee

Accepted Answer

(b) Perigee The text explicitly states, "Once in a month, when the moon's orbit is closest to the earth (perigee), unusually high and low tides occur." Apogee is when the moon is farthest from the earth. Perihelion and aphelion refer to the earth's distance from the sun.

Question 4

Q4: (iv) The earth reaches its perihelion in: (a) October (b) September (c) July (d) January

Accepted Answer

(d) January The chapter mentions, "When the earth is closest to the sun (perihelion), around 3rd January each year, tidal ranges are also much greater..."

Question 5

Q1: (i) What are waves?

Accepted Answer

Waves are the horizontal motion of energy across the ocean surface, not the water itself. Water particles move in a small circle as a wave passes, but it is the wave energy that travels forward. Most waves are generated by the force of wind acting on the water surface.

Question 6

Q2: (ii) Where do waves in the ocean get their energy from?

Accepted Answer

Waves in the ocean primarily get their energy from the wind. Wind blowing against the surface of the water transfers its energy to the water, causing ripples that grow into larger waves. The strength and duration of the wind determine the size and energy of the waves.

Question 7

Q3: (iii) What are tides?

Accepted Answer

Tides are the periodical rise and fall of the sea level, which typically occurs once or twice a day. They are primarily caused by the gravitational attraction of the moon and, to a lesser extent, the sun on the Earth's oceans.

Question 8

Q4: (iv) How are tides caused?

Accepted Answer

Tides are caused by the combined effects of the gravitational forces exerted by the moon and the sun, and the centrifugal force due to the Earth's rotation. These forces together create tidal bulges on opposite sides of the Earth, leading to the regular rise and fall of sea level.

Question 9

Q5: (v) How are tides related to navigation?

Accepted Answer

Tides are crucial for navigation as their predictable nature helps navigators and fishermen plan their activities. High tides are important for ships entering or leaving harbours with shallow bars at the entrance. Tidal currents can also assist or hinder the movement of vessels in bays and estuaries...

Question 10

Q1: (i) How do currents affect the temperature? How does it affect the temperature of coastal areas in the N. W. Europe?

Accepted Answer

Ocean currents significantly affect temperature by transporting vast amounts of water, and therefore heat, from one part of the globe to another. This process is similar to the general circulation of the atmosphere.    Warm currents, like those originating in equatorial regions, move towards the pol...

Question 11

Q2: (ii) What are the causes of currents?

Accepted Answer

Ocean currents are influenced by two types of forces: primary forces that initiate the movement of water and secondary forces that influence its flow. The primary forces that cause ocean currents are:    Heating by Solar Energy: Solar energy heats the water near the equator, causing it to expand. Th...

Question 12

Q1: (i) Visit a lake or a pond and observe the movement of waves. Throw a stone and notice how waves are generated.

Accepted Answer

This project requires a practical observation. Upon visiting a pond or lake and throwing a stone into the water, you should observe the following: 1.  Generation of Waves: The impact of the stone displaces the water at the point of entry. This disturbance creates energy that radiates outwards in the...

Question 13

Q2: (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 a...

Accepted Answer

This activity involves analyzing a map of ocean currents (like Figure 13.3 in the chapter) to understand their characteristics and movements. Your discussion should cover the following points:    Warm and Cold Currents: Identify major currents and classify them. You will notice that warm currents (e...

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