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Lesson 18 of 19

7 min

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Here are the rules this track used. Read them, then try the questions.

Earth, Moon and the Sun — the rules
IdeaThe rule
Two motionsEarth turns once a day. It goes round the Sun once a year.
One faceThe Moon turns once in each trip round Earth. So one face always points at us.
Three in a lineA body in the way makes a shadow. If it lands on another body, that is an eclipse.
Solar eclipseIn a solar eclipse the Moon is between the Sun and Earth. Its shadow lands on a small part of Earth.
Lunar eclipseIn a lunar eclipse Earth is between the Sun and the Moon. Earth shades the Moon.
Not every monthThe Moon's path is tilted about 5°. At most New Moons, its shadow misses Earth.
Watching safelyNever look straight at the Sun, even in an eclipse. A lunar eclipse is safe to watch.
Sun across the skyEarth turns from west to east. The Sun seems to rise in the east. It seems to set in the west.
Day and night placesHalf of Earth faces the Sun, so it is day there. Places in the east see sunrise first.
Pole StarThe Pole Star sits almost over Earth's north pole. So it hardly moves. Other stars circle it.
Night sky in a yearA star rises about 4 minutes earlier each night. After one year it is back at about its first time.
SeasonsEarth's axis leans. In June the north leans toward the Sun. So its sunlight is stronger.
Longest dayIn the north, the longest day is near 21 June. The shortest is near 22 December.

Which motion of Earth causes day and night?

  • Its turning on its own axis
  • Its trip round the Sun
  • The Moon going round it

About how long does Earth take to go once round the Sun?

  • About 24 hours
  • About 365 days and 6 hours
  • About 30 days

We see the same face of the Moon every night. Why?

  • The Moon does not turn
  • The Moon turns once in each trip round Earth
  • The far side is always dark

When does a solar eclipse happen?

  • The Moon is between the Sun and Earth
  • Earth is between the Sun and the Moon
  • The Sun is between Earth and the Moon

When does a lunar eclipse happen?

  • The Moon is between the Sun and Earth
  • Earth is between the Sun and the Moon
  • The Moon is far from Earth

The Moon is much smaller than the Sun. How can it hide the Sun in an eclipse?

  • It is much closer, so both look about the same size
  • It is hotter than the Sun
  • It is bigger than the Sun

Why is there no eclipse every month?

  • The Sun moves away
  • The path of the Moon is tilted, so its shadow usually misses
  • Earth stops turning

Which is a safe way to watch a solar eclipse?

  • Looking straight at it for a second
  • Looking through sunglasses
  • Watching a picture on a screen set up by your teacher

Why does the Sun seem to rise in the east?

  • The Sun moves round Earth
  • Earth turns from west to east
  • Earth goes round the Sun in a day

Two places are far apart. One is in the east. Which sees sunrise first?

  • The one in the east
  • The one in the west
  • Both together

Why does the Pole Star seem to stand still?

  • It is the nearest star
  • It is the brightest star
  • It sits almost over the north pole

A star rises at 11 pm tonight. When will it rise tomorrow?

  • About 4 minutes earlier
  • About 4 minutes later
  • At exactly 11 pm

What gives us the seasons?

  • Earth is nearer the Sun in summer
  • The Sun gives out more heat in summer
  • Earth's leaning axis and its round shape

In the north, near which date is the longest day?

  • 22 December
  • 23 September
  • 21 June

Now open Chapter 12 in your NCERT book. Its eclipse pictures will look familiar.

The next track is The World of Metals and Non-metals. It is a chapter about materials, not the sky.

Reveal every answer to finish this lesson.

That is the end of this subject for Class 7

Nicely done. There is more waiting at this same level — pick whichever you like.