Tides are the rise and fall of seawater caused by the sun and moon's gravitational influences. Tides are primarily formed by the earth's and moon's centrifugal and centripetal forces. The article below briefs the Formation of Tides followed by detailed explanations which is useful for UPSC Geography Syllabus.

Formation of Tides

• The gravitational pull exerted on the Earth by the Sun and the Moon causes tides to form.
• The gravitational pull exerted on the Earth by the Sun and the Moon causes tides to form.
• The Sun's gravitational pull is significantly greater than the Moon's, and this difference is crucial in the formation of tides.
• Tides are classified as either high or low, depending on the size and position of the Sun and Moon.

Types of Tides

Based on Frequency

Semi-Diurnal Tides

• Each day, a semi-diurnal tidal cycle has two almost equal high tides and two low tides.
• The time between high and low tides is around 12 hours and 25 minutes.
• The Indian Ocean is home to the most Semi-Diurnal Tides.
• The following are some of the most common coasts where semidiurnal tides occur: Eastern African Coast and Bay of Bengal.

Diurnal Tides

• It amounts to four times per day.
• The sun produces two tides, while the moon produces two.
• The tide of Spring It's a very high tide brought on by the Sun's complementary role in relation to the moon.
• In a gravitational system, syzygy is the almost straight-line alignment of three celestial bodies (such as the sun, moon, and earth during a solar or lunar eclipse).
• There are two types of syzygy namely
• Conjunction: When the moon and the sun are on the same side, it is called a conjunction.
• Opposition: When the moon and the sun are on opposite sides of the sky. The magnitude of the tide will be the same in both of these situations.

Mixed Tides​

• The mixed tidal cycle, or simply mixed tide, is formed by a tidal cycle with two unequal high and low tides.
• There are semi-diurnal and diurnal oscillations in this tidal cycle.
• It can be found all throughout the Gulf of Mexico and the Caribbean Sea.
• Mixed tides can also be found along the Brazilian coast in the southeast.

Based on the Position of Earth, Sun, and the Moon

Spring Tides

• When the sun and the moon are in alignment, spring tides form, pulling the water surface in the same direction.
• A spring tide occurs when high tides are higher and low tides are lower as a result of this. It happens twice in a lunar month.
• The term 'King Tide' has also been given to it.

Neap Tides​

• Seven days following the spring tide, it occurs.
• The fact that the sun and the moon are at a right angle to each other is the most noticeable feature.
• The first and last quarters of the moon are when this tide happens.
• The moon's gravitational pull and accompanying oceanic bulge are canceled out by the sun's gravitational pull and resulting oceanic bulge.
• In addition, in neap tides, the high tides are 'lower' and the low tides are 'higher' than in spring tides.

Working of Tides

• Understanding the gravitational force of the Sun and Moon can help us understand how tides work.
• The gravitational attraction between these bodies is determined by their mass and the distance between them.
• As the Sun is farther away from the Earth than the Moon, the Earth's gravitational pull is weaker than the moon's.
• As a result, the tide's magnitude is determined by the moon.
• It is commonly assumed that gravitational attraction exclusively affects aquatic bodies, although this is not the case.
• The gravitational force affects both land and sea bodies.
• The influence of gravitation on water bodies is greater because the relative attraction of the land is smaller than that of water.
• It's worth noting that the amplitude of an ant tide is dictated by the Moon's, Sun's, and Earth's relative positions.

Tidal Bulge

• One tidal bulge can be seen on the side of the earth that is closest to the moon.
• The second tidal bulge is visible on the opposite side of the earth from the moon. High tides cause these tidal bulges.
• Under the influence of the moon's gravitational pull, water in the ocean is drawn towards it. This results in a tidal bulge.

Significance

• They have the potential to alter the Earth's landforms.
• While they have the potential to devastate coasts, they also aid in the creation of creeks and inlets.
• Strong tides aid in the formation of the river's lower flood plains.
• The waste is washed away by the sea, and the coast is left clean.
• We can store seawater and collect salt during the tides.

Conclusion

Above all, tides can be used to generate electricity. Tidal currents stabilize the plume bulge near the river mouth and force plume water to flow in the direction of tidal currents, enhancing freshwater transport downstream.

FAQs

MCQs

1. What is the primary cause of tides on Earth?

A) Earth's rotation
B) Gravitational pull of the Moon and Sun
C) Wind patterns
D) Temperature changes in oceans

2. When do spring tides occur?

A) During quarter moons
B) When the Moon is closest to the Earth
C) During full and new moons
D) When the Earth’s axis tilts

3. What is a neap tide?

A) A tide with a large tidal range
B) A tide with the smallest tidal range
C) A tide that occurs during an eclipse
D) A tide with no discernible rise or fall

4. What influences tidal range besides the Moon and Sun?

A) Coastal geography
B) Earth's temperature
C) Ocean salinity
D) Atmospheric pressure

5. What are semidiurnal tides?

A) Tides with one high and one low tide each day
B) Tides with two high and two low tides each day
C) Tides that occur only during neap tides
D) Tides that happen during eclipses

GS Mains Questions and Model Answers

Q1: Explain the formation of tides and discuss the factors influencing tidal patterns globally.

Answer: Tides are formed primarily due to the gravitational pull of the Moon and the Sun on Earth's oceans. The Moon, being closer to Earth, has a greater influence on tides. The alignment of the Sun and Moon during full and new moons leads to spring tides, whereas when they are at right angles during quarter moons, neap tides occur. Factors influencing tidal patterns include the Earth’s rotation, the Moon’s orbit, coastal geography, and the depth of the ocean. Local factors such as the shape of the coastline, seabed topography, and wind also affect the tides in different regions.

Q2: Discuss the significance of tides in coastal and marine environments. How do tides impact human activities?

Answer: Tides play a vital role in coastal ecosystems by facilitating nutrient circulation, assisting in sediment transport, and supporting marine life breeding cycles. Tides also influence human activities such as fishing, shipping, and coastal infrastructure planning. Ports and harbors use tides for navigation, while tidal energy is harnessed as a renewable energy source. However, extreme tides can lead to coastal flooding and pose risks to human settlements.

Q3: Compare and contrast spring tides and neap tides in terms of their formation and effects on tidal range.

Answer: Spring tides occur during the full and new moons when the Earth, Moon, and Sun are aligned, resulting in the highest tidal ranges due to the combined gravitational forces. Neap tides occur during the first and third quarters of the Moon when the Sun and Moon are at right angles to Earth, leading to smaller tidal ranges. Spring tides cause higher high tides and lower low tides, while neap tides produce less variation in sea levels. Both types of tides are part of the regular tidal cycle but differ in their impact on tidal range and coastal activities.

Previous Year Questions on Tides

1. UPSC CSE Prelims 2021:

Question: Which of the following best describes neap tides?

A) Tides with the highest tidal range
B) Tides with the smallest tidal range
C) Tides that occur during eclipses
D) Tides with no noticeable effect on sea levels

Answer: (B)

Explanation: Neap tides are characterized by the smallest tidal range, occurring when the Sun and Moon are at right angles to the Earth during the first and third quarters of the Moon.

2. UPSC CSE Mains 2020 (GS Paper 1):

Question: "Discuss the factors responsible for the formation of tides and their importance for human activities along the coast."

Answer: Tides are primarily caused by the gravitational pull of the Moon and Sun, with the Moon playing a more dominant role. Coastal geography, Earth’s rotation, and wind also affect tidal patterns. Tides are important for navigation, fishing, and the generation of tidal energy. They also influence sediment transport and nutrient cycles in marine ecosystems. However, extreme tidal events can lead to flooding, impacting coastal communities and infrastructure.