CBSE Class 4 EVS Our Sky Worksheet Set 01

Fill in the Blanks

Question. On some nights, the Moon resembles the letter ________.
Answer: C
Explanation: When we only see a tiny sliver of the Moon, it curves beautifully like the letter 'C'. This is called a crescent moon!

Question. The Sun provides us ________ and light.
Answer: heat
Explanation: The Sun is a massive star made of burning gases. It sends energy to Earth in the form of bright light and warm heat.

Question. If the object is close to the origin of light, the shadow becomes ________.
Answer: bigger (or larger)
Explanation: When an object is close to a light source, it blocks a wider angle of light rays, casting a much larger shadow on the wall or ground.

Question. ______ is an instrument used to tell time using shadows.
Answer: Sundial
Explanation: A sundial has a stick that casts a shadow onto a plate with hour lines. As the Sun moves across the sky, the shadow moves to show the correct time.

Question. Shades are longest in the _______ and ____.
Answer: morning, evening
Explanation: When the Sun is low in the sky at dawn and dusk, it shines on objects from a low angle, stretching their shadows very far across the ground.

Question. Early people used the shape of the Moon to keep count of the ________.
Answer: days
Explanation: The Moon completes a full cycle of shapes every 29.5 days. Because this pattern never changes, ancient people counted the days by watching the Moon's phases.

Question. The Sun appears to travel from ________ to ________ during the day.
Answer: East, West
Explanation: Earth spins from West to East. This spin makes the Sun look like it is moving in the opposite direction, rising in the East and setting in the West.

True or False

Question. Shadows are created only in sunlight.
Answer: False
Explanation: Any light source can make a shadow! You can see shadows under streetlights, near candles, or when using a flashlight in your room.

Question. All creatures sleep at night.
Answer: False
Explanation: Some animals are nocturnal, meaning they are active at night and sleep during the day, like owls, bats, and foxes.

Question. The direction of shadows does not shift during the day.
Answer: False
Explanation: As the Sun moves from East to West across the sky, the shadows cast by objects shift directions, always pointing away from the Sun.

Questions / Short Question Answers

Question. How does the sky appear during sunrise and sunset?
Answer: During sunrise and sunset, the sky appears orange and reddish.
Explanation: When the Sun is low near the horizon, its light has to travel through a thicker layer of air. This scatters away other colors and leaves behind beautiful warm shades of orange and red.

Question. Describe different phases of the Moon.
Answer: The Moon changes shape every night—sometimes it is full (Poornima), sometimes half, sometimes a crescent, and sometimes not visible at all (Amavasya).
Explanation: The Moon doesn't actually change shape! As it travels around the Earth, we see different amounts of its sunlit side from our viewpoint.

Question. What is the purpose of the Chandrayaan mission?
Answer: Chandrayaan is India's mission to explore the Moon. In 2023, the Vikram Lander successfully landed on the Moon and gathered important data about its surface.
Explanation: This space mission was sent to study the Moon's surface, look for water ice, and help us learn more about how the Moon was formed.

Question. What conceals the stars during the day?
Answer: Sunlight (or the Sun's bright light).
Explanation: The stars are still in the sky during the day, but the Sun is so close and bright that its light spreads across the sky, making it too bright for us to see the dim stars.

Question. How do shadows assist us?
Answer: Shadows help us understand the position of the Sun and were used in ancient times to tell time using sundials.
Explanation: By looking at where a shadow falls, we can tell where the Sun is in the sky. For a long time, people used this to track the hours of the day!

Question. How do festivals connect to the Moon? Give examples.
Answer: Many festivals are celebrated based on the phases of the Moon. For example, Diwali is celebrated on Amavasya (no Moon), Guru Poornima on a full Moon, and Eid is celebrated after sighting the crescent Moon.
Explanation: People have used lunar calendars for thousands of years to decide when to celebrate special holidays and seasons.

Question. Who am I? “I change my appearance, but don’t wear a mask. I shine at night-that’s my task.”
Answer: The Moon
Explanation: The Moon shines by reflecting light from the Sun, and as it orbits the Earth, its shape appears to change night after night.

Question. Explain how shadows alter during the day.
Answer: Shadows are long in the morning, shortest at noon, and long again in the evening but in the opposite direction.
Explanation: Since the Sun moves across the sky, the angle of light hitting us changes, which stretches or shrinks our shadows throughout the day.

Question. Keep a “Sky Diary” for 5 days, recording what you observe in the sky in the morning, afternoon and night.
Answer: Look at the sky three times a day (morning, afternoon, and night) and write down what you see. You can also draw small pictures to show your observations.
Explanation: Keeping a diary helps you become a young scientist! You will observe how the sky's color, the clouds, and the Moon change every single day.

Question. What is the importance of the Full Moon (Poornima) and the New Moon (Amavasya)?
Answer: The Full Moon (Poornima) is when the Moon appears as a complete circle. The New Moon (Amavasya) is when the Moon is not visible at all in the sky.
Explanation: These represent the two opposite points of the lunar cycle. They are highly important for tracking time and celebrating many traditional festivals.

Question. Write about the path of the Sun in the sky.
Answer: The Sun appears to rise in the East, moves overhead at noon, and sets in the West.
Explanation: The Sun's path across our sky is an illusion caused by the Earth rotating on its axis like a giant spinning top.

Question. What happens to the sky's color as the day passes?
Answer: In the morning, the sky is orange and bright. In the afternoon, it is blue and clear. At night, it turns dark with twinkling stars.
Explanation: The sky changes color because of the angle of sunlight and how it interacts with the air surrounding our planet.

Question. When did Vikram lander safely land on the Moon?
Answer: 23 August, 2023
Explanation: This was a historic day when India became the first country to land a spacecraft safely near the Moon's south pole!

Question. If your shadow is short and directly below you, what time of day is it likely to be?
Answer: It is likely to be noon because at this time, the Sun is directly overhead, so the light falls straight down and creates a short shadow.
Explanation: When light shines directly from above, it doesn't spread out sideways, making your shadow pool right beneath your feet.

Question. Why do shadows in the morning and evening develop in different directions?
Answer: Shadows in the morning and evening form in different directions because the Sun appears to move from East to West. As the position of the Sun changes, the direction of the shadow also changes.
Explanation: Shadows always fall in the opposite direction of the light source. Since the Sun is in the East in the morning, shadows point West; in the evening, the Sun is in the West, so shadows point East.

Question. Name any three holidays that are celebrated based on the Moon.
Answer:
1. Diwali – celebrated on Amavasya (no Moon night)
2. Guru Poornima – celebrated on full Moon
3. Eid – celebrated after the sighting of the new Moon
Explanation: Many of our favorite holidays are scheduled by looking at the phases of the Moon instead of a standard calendar.

Question. How does observing the sky help us understand nature?
Answer: Studying the sky helps us track time, understand natural cycles, and observe celestial events like the movement of the Sun, Moon, and stars.
Explanation: The sky is like nature's calendar. Watching it tells us when to plant crops, when the seasons are changing, and how the solar system works.

Question. What is Chandrayaan Mission? Why is it significant?
Answer: Chandrayaan is India's space program to explore the Moon. It is important because it helps scientists learn about the Moon's soil, temperature, and search for water.
Explanation: Exploring space helps humans discover new things and build new technologies that can help everyone back on Earth.

Question. Describe the shifts in the sky during morning, afternoon, and night.
Answer: The sky appears orange in the morning, bright and blue in the afternoon, and dark with stars and the Moon at night.
Explanation: As the Earth spins, the changing position of the Sun changes the way light passes through our air, coloring the sky beautifully.

Question. What direction do the dusk shadows point?
Answer: East
Explanation: Since the Sun sets in the West in the evening, shadows are cast in the opposite direction, pointing toward the East.

Question. The Sun is the brightest body in the sky. Why cannot we see the stars during the day?
Answer: The Sun’s light is so bright that it hides the light of other stars during the day.
Explanation: Think of the stars like tiny candles and the Sun like a giant searchlight. The searchlight is so bright that you can't even see the candles burning nearby!

Match the Following

Question. Match the items in Column A with the correct choices in Column B:

Answer:

Explanation: "Poornima" refers to the night when the Moon is fully visible (Full Moon eve), while "Amavasya" is when the Moon is completely dark (No Moon eve). Shadows at noon are extremely short because the Sun is overhead, and in the evening, shadows stretch long pointing East because the Sun is in the West.

Question. Match the historical and scientific terms in Column A with their definitions in Column B:

Answer:

Explanation: These matches link Indian astronomical terms and scientific tools to their descriptions. For example, "Saptarshi" is the name for the seven wise stars constellation, and "Chandrayaan" is India's quest to study the Moon.

Vocabulary Activity - "Guess the Word"

Question. The phenomenon where an object obstructs light and forms a dark shape.
Answer: Shadow
Explanation: Light travels in straight lines. When a solid object blocks light from passing through, it creates a dark outline behind it called a shadow.

Question. A cluster of stars known as the Seven Sages in Indian astronomy.
Answer: Saptarshi
Explanation: Saptarshi is a famous group of seven bright stars in the night sky that looks like a giant bowl with a long handle.

Question. The instrument built by Raja Jai Singh that tells time accurately based on shadow.
Answer: Sundial (Samrat Yantra)
Explanation: Raja Jai Singh built massive stone sundials that allowed people to read the exact time of day simply by measuring where a shadow fell.

Question. The period of the day when the Sun is directly overhead and shadows are the shortest.
Answer: Noon
Explanation: At noon, the Sun is at its highest point in the sky. Since the light falls straight down on us, shadows are tiny and stay right under our feet.