Exam practice

Planets go round the Sun.

Heavenly bodies that go round the planets are called satellites.

The Sun is a medium-sized star.

The Moon takes about a month to go round the Earth.

The Moon is the Earth’s only satellite. (“Planet” is not needed.)

(14 is left over: it was once given for Neptune.) These are older counts. As of 2026, Jupiter has 115 known moons and Saturn 293. Mars, Venus and the Earth haven’t changed.

The Sun, the Moon, stars, the planets (such as the Earth, Mars and Jupiter), comets, asteroids and meteors.

• Stars have their own light. Planets have no light of their own; they shine because sunlight falls on them.
• Stars are huge balls of very hot gas. Planets are much smaller and cooler.
• Planets go round the Sun. Stars don’t go round the Sun.
• Stars twinkle. Planets shine with a steady light.

Draw the Sun in the middle, and a big ring (the Earth’s orbit) around it. Draw the Earth on that ring. Draw a small ring around the Earth (the Moon’s orbit), and the Moon on it. Add arrows going the same way round, anticlockwise. Label the Sun, the Earth, the Moon and both orbits.

• The Earth is at the right distance from the Sun. It is not too hot, like Mercury and Venus, and not too cold, like Mars and the planets beyond it.
• It has liquid water.
• It has air, with oxygen to breathe and carbon dioxide for plants.
• Its air keeps the temperature right, and its ozone layer shields life from the Sun’s harmful rays.

Yes. Many other stars have planets going round them. Planets of other stars are called exoplanets. Astronomers found the first ones in the 1990s. As of 2025, more than 6,000 had been found. Some of them have moons too. Scientists are looking for ones that might have water and life.

An imaginary line through the center of the Earth, joining the North and South Poles, is called its axis.

The Earth’s axis is tilted at an angle of 66.5° to the plane of its orbit. (That is 23.5° from straight up.)

If sunlight fell evenly on every side of the spinning Earth, day and night would be equal.

On the Earth, the time in the east is faster (ahead) than the time in the west.

• Daily motion is the Earth spinning on its axis. Annual motion is the Earth going round the Sun.
• Daily motion takes 24 hours (one day). Annual motion takes about 365 days (one year).
• Daily motion gives us day and night. Annual motion, with the tilted axis, gives us the seasons and the change in the length of days.

Any two:

• Day and night.
• The time is different in different places.
• The Sun, the Moon and the stars seem to rise in the east and set in the west.

• There would be no seasons. Each place would have nearly the same weather all year.
• Day and night would be equal (12 hours each) everywhere, every day of the year.

Reason: neither half of the Earth would ever lean towards or away from the Sun. So every place would get the same sunlight all year round.

• The Earth is round. Near the equator, sunlight falls straight down, so it is hot. Near the poles, sunlight falls at a slant and spreads out, so it is cold.
• The Earth’s axis is tilted. When the northern half leans towards the Sun, it has summer while the southern half has winter, and the other way round.
• Height matters too: high mountains, like the Himalaya, are colder than low plains, like the Terai.

At places 1 and 2, the North Pole leans away from the Sun: winter in the north (December). At 5 and 6, it leans towards the Sun: summer in the north (June). At 3 and 4, and at 7 and 8, the axis leans sideways, so day and night are equal everywhere (March and September).

The time from the new moon to the full moon is called the bright half (Shukla Paksha).

One day has 24 hours.

When the Moon is between the Earth and the Sun, it is called the new moon (Aunsi).

The size and brightness of the Moon decrease during the dark half (Krishna Paksha). (“60”, “full moon” and “increase” are not needed.)

The changing shapes of the Moon that we see from the Earth, day by day through a lunar month, are called the phases of the Moon: from the new moon, through a thin curve, a half Moon, to the full moon, and back again.

• New moon: the Moon is between the Sun and the Earth, in one line: Sun, Moon, Earth.
• Full moon: the Earth is between the Sun and the Moon, in one line: Sun, Earth, Moon.

In each drawing, shade the half of the Moon and the half of the Earth that face away from the Sun.

On the new moon day, the Moon is between the Sun and the Earth. The Sun lights up only the half of the Moon that faces it. That lit half faces away from us. The dark half faces the Earth, so we see nothing. The Moon is also in the sky with the Sun, in the daytime, lost in the Sun’s glare.

It would always look full and round, every night. There would be no phases. Reason: its whole face would glow by itself. It would not matter where the Sun was, or which part of it the Sun lit up.

They should start on the full moon day (Purnima), and harvest in the early mornings of the next week or so (Krishna Pratipada to about Krishna Ashtami).
Reasons:

• On Purnima, the full Moon shines all night. Before dawn, it is still in the western sky, big and bright.
• After Purnima, the Moon rises later each night. So it is still high in the sky in the early morning, and it is still fairly big and bright for about a week.
• In the bright half, the Moon sets before dawn: in the evening at first, then later each night. So the hours before sunrise are dark, except for a day or two before Purnima. That is no good for harvesting before sunrise.