Practise Class 8 Science Chapter 11 – Keeping Time with the Skies with this easy NCERT Curiosity worksheet. Includes important questions and revision exercises to strengthen understanding of the sky, time and related scientific concepts and prepare effectively for class tests and exams.

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Class 8 Science – Chapter 11

Keeping Time with the Skies – Fresh Worksheet

Section A – Multiple Choice Questions

1. Why does the Moon appear to have different shapes during a month?

(a) The Moon changes its shape every day

(b) We see different portions of its illuminated side

(d) Clouds cover different parts of the Moon

2. Which phase of the Moon occurs when the illuminated portion facing Earth cannot be seen?

(a) Full Moon

(b) Gibbous Moon

(d) Crescent Moon

3. The Moon takes approximately how long to complete one cycle of its phases?

(a) 7 days

(b) 15 days

(d) 365 days

4. A waning Moon is generally easier to observe around:

(a) Sunrise

(b) Noon

(d) Midnight only

5. A solar year is related mainly to:

(a) Rotation of the Moon

(b) Revolution of Earth around the Sun

(d) Revolution of the Sun around Earth

6. Which calendar mainly follows the phases of the Moon?

(a) Lunar calendar

(b) Solar calendar

(d) Sidereal calendar only

7. What is added in a luni-solar calendar after a few years to keep it in step with the solar year?

(a) Extra day every month

(b) Extra week

(d) Extra season

8. Which of the following is an artificial satellite?

(a) Moon

(b) Earth

(d) Sun

Section B – Fill in the Blanks

1. The Moon shines because it reflects __________ from the Sun.

2. The period during which the bright portion of the Moon increases is called the __________ period.

3. The period during which the bright portion of the Moon decreases is called the __________ period.

4. One complete cycle of the Moon’s phases takes about __________ days.

5. A year based on the cycle of seasons is called a __________ year.

6. The extra day added to February in a leap year makes February have __________ days.

7. Human-made objects that revolve around Earth are called __________ satellites.

8. ISRO stands for Indian Space __________ Organisation.

Section C – True or False

1. The Moon produces its own light.

2. The phases of the Moon are caused by Earth’s shadow falling on the Moon every month.

3. A full Moon occurs when the illuminated portion facing Earth is visible almost completely.

4. The Moon rises at exactly the same time every day.

5. The Gregorian calendar is a solar calendar.

6. Luni-solar calendars use both lunar and solar cycles.

7. Artificial satellites can be used for weather monitoring.

8. Space debris can be harmful to working satellites.

Section D – Match the Following

Column A	Column B
1. New Moon	A. Human-made object orbiting Earth
2. Full Moon	B. Solar calendar
3. Gregorian calendar	C. Illuminated portion is not visible from Earth
4. Artificial satellite	D. Entire illuminated portion faces Earth
5. Luni-solar calendar	E. Uses lunar and solar cycles

Answers:

Section E – Very Short Answer Questions

1. Why can the Moon sometimes be seen during the daytime?

2. What is meant by the phases of the Moon?

3. What is a gibbous Moon?

4. What is a crescent Moon?

5. Why does the Moon rise about 50 minutes later each day?

6. What is a lunar calendar?

7. What is a solar calendar?

8. What is an intercalary month?

9. Name any two uses of artificial satellites.

10. What is space debris?

Section F – Short Answer Questions

1. Explain why the Moon does not have its own light.

2. Why does the shape of the illuminated Moon appear to change even though the Moon itself does not change shape?

3. Explain the difference between waxing and waning of the Moon.

4. Why do lunar calendars gradually lose synchronisation with the seasons?

5. Why are leap years needed in the Gregorian calendar?

6. How do artificial satellites help people on Earth?

Section G – Think and Reason

1. A student says, “The Moon disappears during the new Moon because Earth’s shadow covers it.” Is this explanation correct? Give a reason.

2. Why is a full Moon generally visible for a much longer period during the night than a crescent Moon?

3. Why cannot a purely lunar calendar remain aligned with the seasons for a long time?

4. Why is an artificial satellite able to move around Earth without falling directly onto the ground?

5. Why is space debris considered a problem for space missions?

Section H – Moon Phase Challenge

1. Complete the sequence:

Stage	Moon Phase
Beginning of cycle	________________________
About one week later	________________________
About two weeks later	________________________
About three weeks later	________________________
About four weeks later	________________________

2. Arrange these phases in the correct order:

Full Moon, New Moon, Crescent, Gibbous

3. Draw a simple diagram showing the positions of the Sun, Earth and Moon during a Full Moon.

4. Draw a simple diagram showing the positions of the Sun, Earth and Moon during a New Moon.

Section I – Calendar Challenge

1. Complete the table.

Unit of Time	Natural Cycle
Day	____________________________
Month	____________________________
Year	____________________________

2. A lunar year is about 354 days while a solar year is about 365 days. What is the approximate difference?

3. Why does the Gregorian calendar sometimes have 366 days?

4. What is the main purpose of a luni-solar calendar?

Section J – Artificial Satellites

1. Write any four uses of artificial satellites.

2. Match the satellite or mission with its broad purpose.

Satellite/Mission	Purpose
Cartosat	____________________________
AstroSat	____________________________
Chandrayaan	____________________________
Aditya L1	____________________________

3. What could happen if large pieces of space debris collide with working satellites?

Section K – Application-Based Questions

1. Meena observes a thin crescent Moon shortly after sunset. Is the Moon likely to be waxing or waning? Explain.

2. Rahul observes a bright Moon rising around sunset and remaining visible for most of the night. Which phase is he most likely observing?

3. A village wants to use satellites to receive weather information before heavy rainfall. Which use of artificial satellites is involved?

4. A calendar based only on 12 lunar months is shorter than the solar year. Suggest one method used by luni-solar calendars to correct this difference.

Section L – Numerical and Logical Questions

1. The Moon’s phase cycle is approximately 29.5 days. About how many days are there in two complete phase cycles?

2. A lunar year has approximately 354 days and a solar year has approximately 365 days. Calculate the difference between them.

3. If an artificial satellite takes about 100 minutes to complete one orbit, approximately how many complete orbits could it make in 500 minutes?

4. If the Moon rises approximately 50 minutes later each day, approximately how much later would it rise after 3 days?

Section M – Explore and Create

1. Moon Observation Diary

Observe the Moon for at least seven days. Record its approximate shape, direction and time of observation.

Day	Date	Time	Direction	Moon Shape
1
2
3
4
5
6
7

2. Design a simple calendar based on Moon phases.

Draw the four main stages of the Moon and label them.

3. Space Mission Idea

Imagine that you are a space scientist. Design an artificial satellite for one useful purpose. Write its purpose and what information it would collect.

Section N – Quick Revision

Complete the concept map.

Concept	Key Idea
Moon	________________________________________
Phases	________________________________________
Lunar calendar	________________________________________
Solar calendar	________________________________________
Luni-solar calendar	________________________________________
Artificial satellite	________________________________________

Section O – Challenge Question

Why can two people living in different parts of Earth generally see nearly the same phase of the Moon on the same day?

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Class 8 Science Chapter 11 – Keeping Time with the Skies | NCERT Curiosity Worksheet