Science Chapter 12: Beyond the Earth - Exercises

📘 Chapter 12: Beyond the Earth

📝 “Let us enhance our learning” (Exercises)

Question 1. Match the column:

Column I Column II
(i) Satellite of Earth (d) Moon
(ii) Red planet (c) Mars
(iii) Constellation (a) Orion
(iv) Planet which is commonly called an evening star (b) Venus

Question 2. (i) Solve the following riddle:
My first alphabet is in MAN but not in CAN ➔ M
My second alphabet is in ACE and also in FAN ➔ A
My third alphabet is in RAT and not in CAT ➔ R
My fourth alphabet is in SUN but not in FUN ➔ S
I am a planet that moves around the Sun, so tell me who am I? ➔ MARS

(ii) Make two similar riddles by yourself:

  • Riddle 1 (For VENUS): My first alphabet is in VAN but not in CAN. (V) My second alphabet is in RED and also in BED. (E) My third alphabet is in NET and also in PET. (N) My fourth alphabet is in SUN and also in CUP. (U) My fifth alphabet is in SUN and also in STAR. (S) I am the brightest planet in the night sky. Who am I? ➔ VENUS
  • Riddle 2 (For PLUTO): My first alphabet is in PEN but not in TEN. (P) My second alphabet is in LION and also in LEG. (L) My third alphabet is in SUN and also in CUP. (U) My fourth alphabet is in TOP and also in TOY. (T) My fifth alphabet is in OWL and also in FOX. (O) I was once called the ninth planet, but now I am a dwarf planet. Who am I? ➔ PLUTO

Question 3. Which of the following is not a member of our Solar System?
(i) Sirius (ii) Comets (iii) Asteroids (iv) Pluto

  • Answer: (i) Sirius
  • Reason: Sirius is a star located far outside our Solar System. Comets, asteroids, and Pluto (a dwarf planet) are all members of our Solar System.

Question 4. Which of the following is not a planet of the Sun?
(i) Jupiter (ii) Pluto (iii) Neptune (iv) Saturn

  • Answer: (ii) Pluto
  • Reason: In 2006, the International Astronomical Union (IAU) reclassified Pluto as a 'dwarf planet', so it is no longer considered one of the eight main planets of the Sun.

Question 5. Which is the brighter star, the Pole Star or Sirius?

  • Answer: Sirius
  • Reason: Sirius is the brightest star in the entire night sky, whereas the Pole Star (Polaris) is a relatively faint star.

Question 6. An artist's representation of the Solar System is given in Fig. 12.12. Is the order of the planets correct? If not, write the correct order in the boxes in the figure.

  • Answer: No, the order in the figure is not correct.
  • Correct order of planets in increasing distance from the Sun:
    1. Mercury
    2. Venus
    3. Earth
    4. Mars
    5. Jupiter
    6. Saturn
    7. Uranus
    8. Neptune

Question 7. A portion of night sky with stars is shown in Fig. 12.13. Look carefully and identify the groups of stars that form the patterns—the Big Dipper and the Little Dipper. Draw lines to connect the stars for these patterns and label them. Also, identify and label the Pole Star.

Identification & Labelling Guidance:

  • Big Dipper (Saptarishi): Connect the 7 prominent bright stars that form a large bowl with a handle in Ursa Major.
  • Pole Star (Dhruva Tara): Look at the two pointer stars at the end of the Big Dipper's bowl. Extend an imaginary straight line northwards about 5 times the distance between these two stars; it points directly to the Pole Star.
  • Little Dipper (Ursa Minor): The Pole Star marks the tip of the handle of the Little Dipper.

Question 8. A portion of the night sky is shown in Fig. 12.14. Draw lines to connect the stars for Orion and label the star Sirius.

Identification & Labelling Guidance:

  • Orion (The Hunter): Identify the three bright stars lined up closely in a short straight line at the centre (representing Orion's belt). Connect the surrounding bright stars to outline the hunter's figure.
  • Sirius: Draw an imaginary straight line passing through the three belt stars of Orion towards the east. This line points directly to Sirius, the brightest star in the sky.

Question 9. From Earth, you can see stars fading away at dawn and appearing at dusk. During the day we do not see the stars. Explain why.

  • During the daytime, the Sun shines with intense brightness.
  • Sunlight scatters throughout the Earth's atmosphere, illuminating the sky brightly.
  • Although stars are still present in the sky during the day, their faint light gets completely overpowered by the bright glare of the Sun, making them invisible to us until the Sun sets at dusk.

Question 10. During a clear night, try to observe the Big Dipper 3–4 times at an interval of 2 to 3 hours. Also try to locate the Pole Star each time. Does the Big Dipper appear to move? Draw a rough sketch to illustrate this, mentioning the time in each case.

  • Observation: Yes, the Big Dipper appears to move and rotate around the Pole Star over time. However, the Pole Star itself remains stationary in the North direction.
  • Scientific Reason: The Earth rotates on its axis from west to east. Since the Pole Star lies directly above the Earth's rotational axis in the North, it appears fixed, while the Big Dipper and other constellations appear to revolve around it.

Question 11. Think about the night sky and write a poem or a story on it.

Poem on the Night Sky:

Twinkling stars in the velvet night, Filling the sky with silver light.
Seven bright stars of the Big Dipper shine, Guiding our path in a straight line.
Dhruva Tara stays fixed in the North, As Earth on its axis spins back and forth.
Orion the hunter with his belt of three, Points to Sirius, bright as can be!
Planets and comets, a wondrous sight, Dancing through space in the peaceful night.

🔬 “Learning further” (Projects & Activities)

Names of Planets in Gujarati & Constellation Stories:

  • Mercury: બુધ (Budh)
  • Venus: શુક્ર (Shukra)
  • Earth: પૃથ્વી (Prithvi)
  • Mars: મંગળ (Mangal)
  • Jupiter: ગુરુ (Guru)
  • Saturn: શનિ (Shani)
  • Uranus: યુરેનસ / પ્રજાપતિ
  • Neptune: નેપ્ચ્યુન / વરુણ
  • Indian Story: In Indian astronomy, the Big Dipper is called Saptarishi, named after seven ancient venerated sages.

Light Pollution Impact and Control Measures:

  • Impact: Excessive artificial light at night reduces our ability to view stars, disrupts nocturnal wildlife, wastes electrical energy, and affects human health.
  • Personal Action Plan: Switch off unnecessary outdoor lights at night, use downward-shielded lights to prevent light scattering into the sky, and use energy-efficient motion-sensor bulbs.

Indian Astronomical Observatory, Hanle (Ladakh):

  • Why Hanle was chosen: Located atop Mount Saraswati in Ladakh, Hanle offers high altitude, cloudless skies, dry weather, and virtually zero light or air pollution.
  • Hanle Dark Sky Reserve (HDSR): In December 2022, the area around the observatory was notified as India's first Dark Sky Reserve to promote astro-tourism and astronomical research.

Constellation Embroidery / Art Project:

Using a needle and white/silver thread or sequins, embroider constellation patterns (like Orion or Big Dipper) onto a piece of dark blue or black cloth.

💡 Teacher's Tip: Note down all these answers cleanly in your Science notebook. Keep looking up at the night sky with wonder and curiosity! 🚀✨

Note: If there are any errors in the provided answers or details, please contact us at trhelpmail@gmail.com.