Class 3 Science

The Sun, Moon and Stars – Class 3

The Sun, Moon and Stars

The Sun

The Sun is a star. It is only one of millions and millions of stars in the Galaxy. It is the star closest to the Earth. It is the brightest object in the sky. It is a huge ball of very hot gases. It is made of 92.1% hydrogen gas and 7.8% helium gas. All stars are huge balls of very hot gases. The heat and light of the Sun gives life to the Earth and the Earth would have no life at all without the energy it receives from the Sun. It takes about 8 minutes for the sunlight to reach the Earth after it has left the Sun.

The Sun’s family

Solar System

The Sun and the eight planets that revolves around the Sun are part of the solar system. The Earth is one of these planets. The Earth completes one revolution around the Sun in its orbit in 365 days and 6 hours. The planets do not have their own light. All eight planets of the Sun’ family are mercury, venus, earth, mars, jupiter, saturn, uranus and neptune.

The Sun is at a distance of 149.6 million kilometres from the Earth.

The Moon

The Moon is the only natural satellite of Earth. It is a ball of rock that revolves around our planet Earth. We can see the Moon with our eyes at night. It is our nearest neighbour. We can see the surface of the Moon by using a pair of binoculars or a small telescope. Unlike the Earth, the Moon has no atmosphere.

The Moon has no light of its own. It is lit up by the light from the Sun. When the Moon goes around the Earth, different parts of it are lit by the Sun on different days. We can only see the part that is lit up. Due to this it seems to us that the Moon changes its shape every day.

From the Earth we can only see one side of the Moon, the other side is always turned away from us. When the Moon is between the Sun and the Earth, the side of the Moon facing us does not get sunlight. We cannot see the Moon at all because its dark side faces us. This is called New Moon. After a day or two we see a small portion of the Moon.

After seven days we can see half of the Moon. It is called Half Moon.

Half Moon

Half Moon

After two weeks, the Moon is on the opposite side. The full side facing us gets sunlight. We can then see the Full Moon.

Full Moon

Full Moon

It takes the Moon nearly 28 days to go around the Earth. So the number of days between one New Moon and the next is 28 days.

The first person to walk on the Moon was the American astronaut, Neil Armstrong.

The Stars

As already mentioned above, there are millions and millions of stars in our galaxy and the Sun is one of those stars. On a clear night we can see stars twinkling in the sky. People used their imagination to link several stars together to form a pattern or shape in the sky. These patterns and shapes are called constellations.

There are various names of constellations. It has been named after animals or people from ancient myths. Some of the constellations are The Great Bear, Ursa Major, Ursa Minor, Orion, Scorpius, Leo and Canis Major.

Click Next button for Exercises on the chapter – The Sun, Moon and Stars for Class 3.

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Mamta