Case Study-Beyond Earth-Class 6- Science

Case Study 1: The Night Sky in Nubra

Nubra is a beautiful region in Ladakh. An eleven-year-old girl, Yangdol, and her twin brother, Dorjay, live in one of the villages of this region. They love their surroundings—the majestic mountain peaks and the glaciers—but their favourite is the night sky when the entire sky is lit up with thousands of stars. The weather in Nubra is almost cloudless. With almost no air or light pollution, the night sky is very clearly visible. Night after night, Yangdol and Dorjay observe the stars and experience an immense sense of awe.

Questions & Answers:

1. Why can Yangdol and Dorjay see the night sky so clearly?
   Answer: They can see the night sky clearly because Nubra has almost no air or light pollution, making the stars more visible.

2. What is their favourite part of nature?
   Answer: Their favourite part of nature is the night sky, where they can see thousands of stars.

3. What do they hear from their elders about stars?
   Answer: They hear stories about how certain stars helped caravans find their way in ancient times.

4. Why is Nubra a good place for stargazing?
   Answer: Nubra has cloudless weather and no light pollution, which makes the stars appear bright and clear.

5. What emotions do the children feel when they observe the stars?
   Answer: They feel an immense sense of awe and curiosity while observing the night sky.

Case Study 2: Stars and Constellations

At night, when we look up at the sky, we see many stars. Some stars are bright and others are dim. Stars shine with their own light. Some groups of stars appear to form patterns which are like shapes of familiar things. Long ago, when watching stars in the night sky was a favourite pastime of our ancestors, they identified these star patterns with animals, things, or characters in stories. Many cultures had names for patterns based on their own stories. These imaginary shapes helped them in recognising stars in the sky.

Questions & Answers:

1. What are constellations?
   Answer: Constellations are groups of stars that form patterns in the sky, often resembling animals or objects.

2. How did ancient people use constellations?
   Answer: They used them for navigation and created stories about them based on their shapes.

3. Do all stars have the same brightness? Why or why not?
   Answer: No, some stars appear brighter because they are either closer to Earth or naturally emit more light.

4. Name a famous constellation and describe its shape.
   Answer: Orion is a famous constellation, often represented as a hunter with a belt of three bright stars.

5. How many constellations are officially recognized today?
   Answer: There are 88 officially recognized constellations.

Case Study 3: The Solar System

The Sun is a star. It is the star closest to us. It is an extremely hot spherical ball of gases. The Sun gives out a huge amount of energy, and that is why it glows so brightly. The Sun, being the brightest object and the source of light and heat on Earth, was elevated in most ancient civilizations to the status of a deity. The heat provided by the Sun keeps the Earth at a temperature that makes life possible. Sunlight is essential for plants to grow, which provide food and oxygen to animals, including humans.

Questions & Answers:

1. What is the Sun made of?
   Answer: The Sun is a spherical ball of extremely hot gases.

2. Why does the Sun appear so bright?
   Answer: The Sun gives out a huge amount of energy in the form of light and heat.

3. Why is the Sun important for life on Earth?
   Answer: The Sun provides heat, light, and energy for plants to grow, which helps sustain life.

4. Why do ancient civilizations worship the Sun?
   Answer: Since the Sun is the main source of life, many ancient cultures considered it a deity.

5. How far is the Sun from Earth?
   Answer: The Sun is about 150 million km away from Earth.

Case Study 4: The Moon and Satellites

The Moon is Earth’s natural satellite. It takes about 27 days to complete one revolution around the Earth. It is our nearest neighbour in space. Unlike on Earth, there is hardly any atmosphere on the Moon. The Moon’s surface shows circular bowl-like structures called craters. Most of these craters have been formed due to the impact of asteroids or rocks from space hitting the Moon’s surface. Since there is no atmosphere, water, or life on the Moon, these features stay on the Moon’s surface for a very long time.

Questions & Answers:

1. What is the Moon?
   Answer: The Moon is Earth’s natural satellite that revolves around Earth in about 27 days.

2. Why does the Moon have craters?
   Answer: Craters are formed by the impact of asteroids and space rocks hitting the Moon’s surface.

3. Why do features on the Moon remain unchanged for a long time?
   Answer: Since there is no atmosphere, water, or life, the surface does not experience weathering or erosion.

4. Why is the Moon called Earth’s nearest neighbour?
   Answer: The Moon is the closest celestial body to Earth, located about 384,000 km away.

5. What missions has India sent to the Moon?
   Answer: India has launched Chandrayaan-1 (2008), Chandrayaan-2 (2019), and Chandrayaan-3 (2023) to study the Moon.

Case Study 5: The Milky Way Galaxy and the Universe

In the moonless night sky, viewed from dark locations away from city lights, one can see an extended faint band of light from near north to south across the sky. This is our home galaxy called the Milky Way Galaxy or Ākāśha Gangā. A galaxy has millions to billions of stars. Our Solar System is part of the Milky Way Galaxy. Scientists study other galaxies in the universe to understand more about stars, planets, and life beyond Earth.

Questions & Answers:

1. What is the Milky Way Galaxy?
   Answer: The Milky Way is the galaxy in which our Solar System exists, containing billions of stars.

2. What is a galaxy?
   Answer: A galaxy is a vast collection of stars, planets, gas, and dust bound together by gravity.

3. What do scientists search for in other galaxies?
   Answer: Scientists look for stars, planets, and the possibility of life beyond Earth.

4. What is an exoplanet?
   Answer: An exoplanet is a planet that orbits a star outside our Solar System.

5. Can we see the Milky Way with our eyes?
   Answer: Yes, on a clear moonless night away from city lights, the Milky Way appears as a faint band of light in the sky.