Samacheer Kalvi Class 5 Social Science Solutions Term 1 Chapter 1 Our Earth

Evaluation

I. Fill in the blanks.

Question 1. The distance between the earth and the sun is _______.
Answer: The distance between the Earth and the Sun is about 150 million kilometers. This vast distance allows Earth to receive enough sunlight for life to thrive, but not too much to burn up.
In simple words: The Earth is nearly 150 million kilometers away from the Sun.

🎯 Exam Tip: Remember the approximate distance between Earth and the Sun, as it's a key astronomical fact. "Nearly" or "approximately" is acceptable if the exact number isn't recalled.

Question 2. ______ are caused due to revolution of the Earth.
Answer: Seasons are caused because the Earth revolves around the Sun. As the Earth moves in its orbit, different parts of it get more direct sunlight at different times of the year, creating the distinct seasons we experience.
In simple words: The Earth moving around the Sun causes seasons.

🎯 Exam Tip: Distinguish between rotation (day and night) and revolution (seasons) carefully in your answers.

Question 3. The continent ______ is covered by ice.
Answer: The continent of Antarctica is almost entirely covered by a thick layer of ice. It is the coldest continent on Earth and is home to unique wildlife like penguins.
In simple words: Antarctica is the continent covered in ice.

🎯 Exam Tip: Know the unique characteristics of each continent, such as its climate or key features.

Question 4. The biggest continent is _______.
Answer: Asia is the largest continent in the world. It covers a vast area and has the largest population of any continent.
In simple words: Asia is the biggest continent.

🎯 Exam Tip: Remember both the largest and smallest continents for quick recall.

Question 5. ______ is described as Red Planet.
Answer: Mars is known as the Red Planet. Its reddish appearance comes from iron oxide, which is like rust, on its surface.
In simple words: Mars is called the Red Planet.

🎯 Exam Tip: Be familiar with the common nicknames for planets, as they often relate to their visible characteristics.

Question 6. Percentage of our earth is covered by salt water.
Answer: About 71% of our Earth's surface is covered by salt water. This huge amount of water forms the oceans and is essential for Earth's climate and ecosystems.
In simple words: 71% of the Earth is covered by salty ocean water.

🎯 Exam Tip: Remember the approximate percentages of land and water on Earth's surface.

II. Match the Following

Question. Match the following:
1. Smallest continent - (a) Earth's revolution
2. Blue planet - (b) Australia
3. Neptune - (c) Earth
4. Seasons - (d) earth's rotation
5. Day and night - (e) farthest planet
Answer:
1. (b) Australia
2. (c) Earth
3. (e) farthest planet
4. (a) Earth's revolution
5. (d) earth's rotation
In simple words: Match each item to its correct description or related concept. Smallest continent is Australia, Earth is the blue planet, Neptune is the farthest, seasons are from revolution, and day/night from rotation.

🎯 Exam Tip: Read all options carefully before matching. Sometimes, more than one option may seem plausible until you consider the best fit.

III. Short Question and Answers:

Question 1. What do you know about Universe?
Answer: The Universe is a huge and endless stretch of space. It contains many billions of galaxies, which themselves have countless stars, planets, dwarf planets, comets, asteroids, meteoroids, and natural satellites. We do not yet know the exact size of the universe, but scientists believe it is always growing outwards. This incredible expansion has been going on for billions of years.
In simple words: The Universe is a vast space with billions of galaxies. These galaxies contain stars, planets, and other space objects. It is still growing.

🎯 Exam Tip: When describing the Universe, emphasize its vastness, what it contains (galaxies, stars, planets), and its continuous expansion.

Question 2. Define solar system.
Answer: A solar system is a group of objects that are all held together by gravity around a central star. Our own Solar System includes the Sun, all the planets, their moons, dwarf planets, asteroids, and comets. All these objects orbit the Sun because of its strong gravitational pull, creating an organized cosmic dance.
In simple words: A solar system is the Sun and everything that orbits it, like planets, moons, and asteroids, all held by gravity.

🎯 Exam Tip: When defining the solar system, remember to mention the Sun as the central star and the role of gravity in holding everything together.

Question 3. How did the Earth form?
Answer: The Earth formed about 4.54 billion years ago. At first, our Solar System was just a big cloud of dust and gas called the Solar Nebula. Then, because of a big explosion, the tiny particles in this cloud started to pull together and spin, with the Sun forming in the center. Over time, larger particles combined to make the planets, including our Earth. This process of accretion gradually built up the planet we live on.
In simple words: The Earth formed about 4.54 billion years ago from a cloud of dust and gas called the Solar Nebula. Particles in this cloud came together and spun, forming planets after an explosion.

🎯 Exam Tip: Key terms like "Solar Nebula" and "gravitational collapse" are important when explaining Earth's formation.

Question 4. Distinguish between Rotation and Revolution.
Answer:

🎯 Exam Tip: For "distinguish" questions, always use a table format with clear, concise points of difference for full marks.

Question 5. How many oceans are there in the earth?
Answer: There are five main oceans on Earth. These massive bodies of salt water cover most of our planet's surface and are crucial for weather patterns and marine life.
1. Pacific Ocean
2. Atlantic Ocean
3. Indian Ocean
4. Arctic Ocean
5. Southern Ocean
In simple words: There are five oceans on Earth: Pacific, Atlantic, Indian, Arctic, and Southern.

🎯 Exam Tip: List all five oceans correctly and ensure their names are spelled accurately.

IV. Paragraph:

Question 1. Write about the solar system.
Answer: Our solar system consists of eight planets that orbit our Sun. These planets are divided into two main types. The inner planets are rocky and include Mercury, Venus, Earth, and Mars; these are also known as Terrestrial Planets. The outer planets are much larger and are made mostly of gas or ice, known as Gaseous or Frozen Planets. These include Jupiter, Saturn, Uranus, and Neptune. All these celestial bodies, along with moons, asteroids, and comets, are held in orbit around the Sun by its powerful gravity. The Sun's gravity keeps everything in our solar system organized and moving.
In simple words: Our solar system has eight planets orbiting the Sun. Inner planets (Mercury, Venus, Earth, Mars) are rocky. Outer planets (Jupiter, Saturn, Uranus, Neptune) are gaseous or frozen.

🎯 Exam Tip: When describing the solar system, mention the number of planets, differentiate between inner (rocky/terrestrial) and outer (gaseous/frozen) planets, and name them correctly.

Question 2. Write about the Planet Earth in detail.
Answer: Planet Earth is often called the Blue Planet because of the large amount of water on its surface. It is made up of seven continents and five oceans, which together form its unique geography. Humans and many other living things thrive on Earth's surface. A significant portion, about 71%, of our planet is covered by salty ocean water. The largest continent on Earth is Asia, while Australia is the smallest. Earth is the only known planet that can support life, making it truly special in our solar system.
In simple words: Earth is called the Blue Planet. It has seven continents and five oceans, with 71% covered by salt water. Asia is the largest continent, and Australia is the smallest. It is where we live.

🎯 Exam Tip: For detailed descriptions of Earth, include its nickname, composition (continents/oceans), water percentage, and the biggest/smallest continents.

Question 3. Explain about the continents.
Answer: Earth is divided into seven large landmasses called continents, surrounded by five oceans. These continents are Asia, Africa, North America, South America, Antarctica, Europe, and Australia. Each continent has its own unique geography, climate, and ecosystems. Asia is the biggest continent, covering the largest land area and holding the most people, while Australia is the smallest. Antarctica is a unique continent known for being covered almost entirely by snow and ice, making it the coldest place on Earth. Understanding continents helps us study global geography.
In simple words: Earth has seven continents: Asia, Africa, North America, South America, Antarctica, Europe, and Australia. Asia is the biggest, and Australia is the smallest. Antarctica is covered in snow.

🎯 Exam Tip: Be sure to name all seven continents and include facts about the largest, smallest, and most unique (like Antarctica).

Samacheer Kalvi 5th Social Science Guide Our Earth Additional Questions and Answers

I. Fill in the blanks.

Question 1. The Earth is the _______ planet from the sun.
Answer: The Earth is the third planet from the Sun. Its position in the solar system is just right for life to exist.
In simple words: Earth is the third planet from the Sun.

🎯 Exam Tip: Memorize the order of planets from the Sun, as this is a common knowledge check.

Question 2. _______ day and night are caused due to the earth's _______.
Answer: Day and night are caused due to the Earth's rotation. As the Earth spins on its axis, different parts of it face the Sun, creating day, while the other side experiences night.
In simple words: Day and night happen because of the Earth's rotation.

🎯 Exam Tip: Clearly link rotation to day/night and revolution to seasons to avoid confusion.

Question 3. Universe is also referred to us _______.
Answer: The Universe is also referred to as the cosmos. This term emphasizes the orderly and harmonious nature of the universe, despite its vastness.
In simple words: The Universe is also called the cosmos.

🎯 Exam Tip: Know synonyms for common scientific terms, like "Universe" and "cosmos."

Question 4. _______ is called Earth's twin.
Answer: Venus is often called Earth's twin. It is similar to Earth in size and mass, but its environment is very different and harsh.
In simple words: Venus is called Earth's twin.

🎯 Exam Tip: Understand why planets are given certain nicknames, as it often reflects a key characteristic.

Question 5. The continent full of snow is _______.
Answer: Antarctica is the continent full of snow. It is a unique landmass completely covered by a thick ice sheet, making it the world's largest desert in terms of precipitation.
In simple words: Antarctica is the continent covered fully in snow.

🎯 Exam Tip: Associate key geographical features with their respective continents.

Question 6. Only _______ percent of water is fresh in earth.
Answer: Only about 2.5 percent of the water on Earth is fresh water. Most of this fresh water is locked up in glaciers and ice caps, making only a small fraction available for human use.
In simple words: Only 2.5 percent of water on Earth is fresh.

🎯 Exam Tip: Remember the small percentage of available fresh water to highlight its importance and conservation needs.

Question 7. Birla Planetarium is located in _______.
Answer: Birla Planetarium is located in Chennai. It is a popular educational center where people can learn about astronomy and space.
In simple words: The Birla Planetarium is in Chennai.

🎯 Exam Tip: For location-based questions, simply state the city or place correctly.

Question 8. Galaxy is the huge cluster of _______.
Answer: A galaxy is a huge cluster of stars. It also contains gas, dust, and dark matter, all bound together by gravity. Our own Milky Way is an example of a galaxy.
In simple words: A galaxy is a big group of stars.

🎯 Exam Tip: Define key astronomical terms accurately, such as what constitutes a galaxy.

II. Match the following:

Question. Match the following:
1. Blue Planet - (a) Mars
2. Ringed planet - (b) Earth
3. Earth's Twin - (c) Mercury
4. Smallest planet - (d) Venus
5. Red planet - (e) Saturn
Answer:
1. (b) Earth
2. (e) Saturn
3. (d) Venus
4. (c) Mercury
5. (a) Mars
In simple words: Match the planet nicknames: Blue Planet is Earth, Ringed planet is Saturn, Earth's Twin is Venus, Smallest planet is Mercury, and Red planet is Mars.

🎯 Exam Tip: Double-check your matches, especially for planets with similar characteristics or nicknames.

III. Short Question and Answers:

Question 1. What is the galaxy?
Answer: A galaxy is a huge group of billions of stars, along with gas, dust, and dark matter. These are all held together in space by gravity. Our home galaxy is called the Milky Way, which is just one of countless galaxies in the entire Universe. Galaxies come in different shapes and sizes.
In simple words: A galaxy is a very large group of stars, gas, and dust held together by gravity.

🎯 Exam Tip: Define a galaxy by mentioning its components (stars, gas, dust) and the force that binds them (gravity).

Question 2. How many continents are there in the earth?
Answer: There are seven continents on Earth. These large landmasses are separated by oceans and each has distinct features. The seven continents are Asia, Africa, North America, South America, Antarctica, Europe, and Australia.
In simple words: There are seven continents on Earth: Asia, Africa, North America, South America, Antarctica, Europe, and Australia.

🎯 Exam Tip: Ensure you list all seven continents correctly and completely for full marks.

Question 3. Which are the biggest and smallest continents in our earth?
Answer: On our Earth, Asia is the biggest continent. It is known for its vast land area and large population. The smallest continent is Australia, which is also an island country. Knowing the extremes helps understand global geography.
In simple words: Asia is the biggest continent, and Australia is the smallest.

🎯 Exam Tip: Clearly state both the biggest and smallest continents in your answer.

IV. Answer in Paragraph:

Question 1. Why is Mars called the red planet?
Answer: Mars is known as the Red Planet because of its distinct reddish appearance. This color comes from the iron oxide, which is essentially rust, present on its surface and in its atmosphere. Mars is the fourth planet from the Sun and is the second smallest planet in our solar system, with Mercury being the smallest. Historically, it was named after the Roman God of War due to its blood-red hue. The presence of iron-rich dust causes this characteristic color, making it easily recognizable in the night sky. The red color is a defining feature of Mars.
In simple words: Mars is called the Red Planet because its surface contains iron oxide, which is like rust, giving it a red color. It's the fourth planet from the Sun and was named after the Roman God of War.

🎯 Exam Tip: When explaining why Mars is red, remember to mention "iron oxide" (rust) as the primary reason and its historical naming convention.

V. Map work:

Question 1. On a world map mark the five oceans and Continents of the Earth.
Answer: A world map shows the arrangement of all the continents and oceans. The seven continents are: North America, South America, Europe, Africa, Asia, Australia, and Antarctica. The five oceans are: the Pacific Ocean (which is both east and west of the Americas), the Atlantic Ocean (between the Americas, Europe, and Africa), the Indian Ocean (south of Asia), the Arctic Ocean (around the North Pole), and the Southern Ocean (around Antarctica). These geographical features are crucial for understanding global locations.
In simple words: The map shows seven continents (North America, South America, Europe, Africa, Asia, Australia, Antarctica) and five oceans (Pacific, Atlantic, Indian, Arctic, Southern).

🎯 Exam Tip: Practice identifying and labeling all continents and oceans on a blank world map for good geographical knowledge.

Question 2. On a world map mark the deserts and forests.
Answer: A world map can show the locations of major deserts and forests. Important deserts include: the Sahara Desert (Africa), Kalahari Desert (Africa), Thar Desert (Asia), Gobi Desert (Asia), and Atacama Desert (South America). Major forest areas include: the Amazon Forest (South America), Congo Forest (Africa), and large forest regions across North America, Europe, and Asia. These regions highlight the diverse climates and biomes across the globe.
In simple words: The map shows deserts like Sahara, Kalahari, Thar, Gobi, Atacama, and forests like Amazon and Congo, along with forest areas in North America, Europe, and Asia.

🎯 Exam Tip: Be able to locate significant deserts and major forest belts on a world map, understanding their general positions relative to continents.