NCERT Class 8 Science Curiosity: Chapter 11 — Keeping Time with the Skies
This chapter, "Keeping Time with the Skies," from NCERT's Class 8 Science Curiosity textbook, explores celestial phenomena related to timekeeping. It begins by posing intriguing questions about observing the Moon during the day, imagining life on the Moon, and the impact of multiple moons. The chapter then delves into the practical observation of the Moon's changing appearance over a month through Activity 11.1. Students are guided to document the Moon's visibility, its bright and dark portions, and its position relative to the Sun at sunrise and sunset. This hands-on approach aims to help students understand the lunar cycle and its connection to measuring time, reinforcing concepts crucial for CBSE science learning.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 8 |
| Subject | Science |
| Book | Curiosity |
| Chapter | Chapter 11 — Keeping Time with the Skies |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 2 minutes |
| Word count | 347 |
Learning outcomes
- Understand why the Moon is sometimes visible during the day.
- Describe how the Moon's appearance changes over a month.
- Relate the Moon's phases to its position relative to the Sun and Earth.
- Appreciate the role of celestial bodies in measuring time.
- Conduct observational activities to document lunar changes.
Vocabulary
| Word | Meaning |
|---|---|
| Makar Sankranti | A Hindu festival celebrating the sun's transition into Capricorn. |
| Patang Mahotsav | International Kite Festival. |
| Lunar eclipse | An event where the Earth passes between the Sun and the Moon, casting a shadow on the Moon. |
| Spherical | Having the shape of a sphere. |
| Reflecting | Bouncing back light or heat. |
| Sunrise | The time in the morning when the sun appears. |
| Sunset | The time in the evening when the sun disappears below the horizon. |
| Full Moon | The phase of the Moon when it appears fully illuminated from Earth. |
The complete chapter text is read in the official NCERT PDF viewer below (streamed from ncert.nic.in). This page provides NCERT Help study material — summary, vocabulary, practice questions, and FAQs — not a full reproduction of the textbook.
Read chapter online
This PDF is loaded from the official NCERT website (ncert.nic.in). Use the page buttons below to read — download is disabled on NCERT Help.
Read page by page below. PDF is streamed from the official NCERT website — no download button on this page.
Practice questions
- Why might Meera have been surprised to see the Moon during the day? Answer: Meera was surprised because she had always thought the Moon appeared only at night.
- What does it mean for the Moon to shine by reflecting sunlight? Answer: It means the Moon does not produce its own light but is visible because it bounces back the light from the Sun.
- What is the Patang Mahotsav? Answer: The Patang Mahotsav is the International Kite Festival.
- What should you document in Activity 11.1 regarding the Moon's appearance? Answer: You should document the date, time of observation (sunrise/sunset), the bright portion of the Moon, whether the bright portion is increasing or decreasing, and the Moon's position relative to the Sun.
Frequently asked questions
Why is the Moon sometimes visible during the day?
The Moon is sometimes visible during the day because it is bright enough to be seen even when the Sun is up, and its position in the sky allows for daytime visibility.
What causes the Moon's shape to appear to change?
The apparent change in the Moon's shape, known as phases, is caused by the changing angles at which we view the Moon's illuminated surface as it orbits the Earth.
How does the Moon shine?
The Moon shines by reflecting sunlight.
What is a full Moon day?
A full Moon day is when the entire face of the Moon visible from Earth is illuminated by the Sun.
What is the purpose of Activity 11.1?
Activity 11.1 is designed to help students observe and document the Moon's changing appearance over a month to understand its cycle.
When is it easiest to spot the Moon in the sky for Activity 11.1?
It is easiest to spot the Moon in the sky for Activity 11.1 on the sunrise after a full Moon day.
Related resources
Important topics
Topics covered
NCERT Class 8 Science — Curiosity — Chapter 11 — Keeping Time with the Skies. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.