NCERT Class 8 Science Curiosity (Sanskrit): Chapter 11 — अध्यायः ११ आकाशेः सह कालयापनम्
This chapter, "आकाशैः सह कालयापनम्" (Spending Time with the Sky) from NCERT Class 8 Science Curiosity, delves into the fascinating phenomena of the sky. It begins by prompting critical thinking about observing the moon during the day and understanding the reasons behind the sun's visibility. The chapter encourages students to imagine life on the moon and ponder the concepts of a day, month, and year in such a context. It poses intriguing questions about the effects of having two moons or the absence of clocks and calendars, emphasizing how we measure time. The text then narrates an anecdote about observing the moon during a festival, sparking curiosity about its changing shape and visibility. It introduces the concept that the moon reflects sunlight and explores why a full moon isn't visible every night, touching upon eclipses and the moon's phases. The chapter includes an activity to observe and record the moon's changing appearance over a month, fostering a deeper understanding of celestial cycles and their relation to timekeeping. This chapter aims to enhance students' observational skills and scientific inquiry regarding astronomical events.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 8 |
| Subject | Science |
| Book | Curiosity (Sanskrit) |
| Chapter | Chapter 11 — अध्यायः ११ आकाशेः सह कालयापनम् |
| Language | Sanskrit |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 2 minutes |
| Word count | 254 |
Learning outcomes
- Understand why the moon is sometimes visible during the day.
- Explain the concept of the moon reflecting sunlight.
- Observe and record the changing phases of the moon.
- Relate celestial observations to the measurement of time.
- Develop critical thinking about astronomical phenomena.
Vocabulary
| Word | Meaning |
|---|---|
| सूक्ष्मचिन्तनं | Critical thinking |
| प्रमाणीकरणं | Verification/Validation |
| उदेति | Rises |
| कल्पयतु | Imagine |
| पृष्ठिव्याः | Of the Earth |
| उप.रि | On/Above |
| मासः | Month |
| वर्षः | Year |
| घटिकाः | Clocks |
| पञ्चाङ्गानि | Calendars |
| मापनं | Measurement |
| अन्तर्राष्ट्रिय-वाताट-उत्सवस्य | International Kite Festival |
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Practice questions
- During which festival did Mira observe the moon during the day? Answer: Mira observed the moon during the International Kite Festival.
- What did Mira realize about the moon's visibility? Answer: Mira realized that the moon is not only visible at night but can also be seen during the day.
- What is the reason for the moon's light, according to the chapter? Answer: The moon reflects sunlight, which makes it appear luminous.
- What is the suggested activity to understand the moon's changing shape? Answer: The activity involves observing and recording the moon's appearance daily for about 15 days, starting from a full moon day.
- Why might one not be able to see the moon after approximately 15 days? Answer: After approximately 15 days, the moon might not be visible at sunrise or sunset, possibly due to its phase or position relative to the sun and Earth.
Frequently asked questions
Can the moon be seen during the day?
Yes, the moon can sometimes be seen during the day, especially when it is bright and the sky is clear.
Why does the moon appear to change its shape?
The moon appears to change its shape because we see different amounts of its sunlit surface as it orbits the Earth. This is due to the changing angles at which we view the sunlit portion.
What is the source of light from the moon?
The moon does not produce its own light; it shines because it reflects the light from the sun.
What is the purpose of Activity 11.1?
Activity 11.1 is designed to help students understand how the moon's shape changes over time by observing and recording its appearance daily.
How does observing the moon help in understanding time?
Historically, the regular changes in the moon's phases were used to measure months and keep track of time before the invention of modern clocks and calendars.
What is a lunar eclipse?
A lunar eclipse is a rare and brief event that occurs when the Earth passes directly between the sun and the moon, casting a shadow on the moon.
Related resources
Important topics
Topics covered
NCERT Class 8 Science — Curiosity (Sanskrit) — Chapter 11 — अध्यायः ११ आकाशेः सह कालयापनम्. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.