All questions of Changes in the Earth Surface for Year 4 Exam

Understanding Earth's Seasons
Earth experiences seasons primarily due to the tilt of its axis. Here are the key points explaining this concept:
1. Earth's Axial Tilt
- Angle of Tilt: Earth's axis is tilted at an angle of approximately 23.5 degrees.
- Impact of Tilt: This tilt means that as Earth orbits the Sun, different parts of the planet receive varying amounts of sunlight throughout the year.
2. Variation in Sunlight
- Summer and Winter: When the Northern Hemisphere is tilted towards the Sun, it experiences summer with longer days and more direct sunlight. Conversely, when it is tilted away, it experiences winter with shorter days and less direct sunlight.
- Spring and Autumn: During spring and autumn (or fall), both hemispheres receive roughly equal sunlight, resulting in moderate temperatures.
3. Not Distance from the Sun
- Misconception: It is a common misconception that the distance from the Sun causes seasons. However, Earth's orbit is nearly circular, and the distance changes very little over the course of the year.
4. Role of the Moon and Rotation
- Moon's Influence: The Moon does not significantly affect the seasons. Its primary role involves tides.
- Earth's Rotation: While Earth's rotation affects day and night, it does not impact seasonal changes.
Conclusion
Understanding the tilt of Earth's axis helps explain why we experience different seasons, making option 'B' the correct answer. This tilt is fundamental in shaping our climate patterns and the rhythm of life on our planet.

The primary component of the atmosphere of Mars is carbon dioxide, which makes up about 95% of the Martian atmosphere. This thin atmosphere contributes to the planet's cold temperatures and inability to support human life without significant technological aid.

Understanding Moons in Our Solar System
In our solar system, different planets have varying numbers of moons. Among them, Saturn stands out for having the most moons.
Why Saturn Has the Most Moons
- Saturn is a gas giant, and its massive size allows it to capture and hold onto more celestial objects in its gravitational pull.
- As of now, Saturn has 83 confirmed moons, surpassing Jupiter, which has 80 moons.
Comparison of Planetary Moons
- Earth:
- Earth has only 1 moon, known as the Moon.
- Mars:
- Mars has 2 small moons, Phobos and Deimos, which are thought to be captured asteroids.
- Jupiter:
- Jupiter, the largest planet, has 80 moons, including the four largest known as the Galilean moons: Io, Europa, Ganymede, and Callisto.
Significance of Saturn's Moons
- Saturn's moons vary in size and composition, from large moons like Titan, which is bigger than the planet Mercury, to many smaller irregularly shaped moons.
- The diversity of Saturn's moons provides valuable insights into the formation and evolution of the solar system.
Conclusion
In conclusion, Saturn holds the title for the most moons in our solar system, making it an intriguing subject for astronomers and space enthusiasts alike. The continuous study of these moons can help us uncover more about the dynamics of celestial bodies and the history of our cosmic neighborhood.

Neptune is not a terrestrial planet; it is a gas giant. Terrestrial planets, like Earth, Mars, and Venus, are composed primarily of rock and metal.

Planet known as the "Morning Star" or "Evening Star"

Venus
Venus is known as the "morning star" or "evening star" because it is often the first "star" that appears in the sky in the morning before sunrise or the last one visible in the evening after sunset.

Reason behind the name
The reason behind this nickname is due to the planet's brightness and proximity to Earth. Venus is the second planet from the Sun and is often visible to the naked eye due to its thick clouds reflecting sunlight.

Visibility
Venus can be seen in the morning just before sunrise in the east or in the evening just after sunset in the west. Its brightness can outshine most stars in the sky, making it easily recognizable.

Importance in ancient cultures
Venus has been observed and studied for centuries by various ancient civilizations. It was often associated with goddesses of love and beauty due to its striking appearance in the sky.

Conclusion
In conclusion, Venus is known as the "morning star" or "evening star" because of its brightness and visibility in the sky during these times. Its unique characteristics have made it a fascinating object of study and observation throughout history.

Fastest Winds in the Solar System
Neptune holds the record for the fastest winds in our solar system, surpassing the winds of other planets like Jupiter, Saturn, and Uranus.
Wind Speeds on Neptune
- Neptune's wind speeds can reach up to 1,500 miles per hour (2,400 kilometers per hour).
- These high-speed winds are primarily found in its atmosphere, where strong storms frequently occur.
Comparison with Other Planets
- Jupiter: While Jupiter has powerful storms, such as the Great Red Spot, its wind speeds generally reach around 400 miles per hour (640 kilometers per hour).
- Saturn: Saturn experiences winds of about 1,100 miles per hour (1,800 kilometers per hour) at its equator, but this is still slower than Neptune's strongest winds.
- Uranus: The wind speeds on Uranus can top out at about 400 miles per hour (640 kilometers per hour), similar to Jupiter but still not as fast as Neptune.
Reasons for High Wind Speeds
- Neptune's atmosphere consists of hydrogen, helium, and methane, contributing to its dynamic weather patterns.
- The planet's significant distance from the Sun leads to extreme temperature differences, which can generate strong winds.
In summary, Neptune's unique atmospheric conditions and positioning contribute to its record-breaking wind speeds, making it the planet with the fastest winds in the solar system.

During summer in the northern hemisphere, the north pole has sunshine all the time. This means it is always daytime there, and the sun does not set for six months.

Mars is known as the Red Planet because its surface is covered with red dust, giving it a reddish appearance. Interestingly, this red dust is due to iron oxide, commonly known as rust.