Page 90 - Active Science 5 Ebook and Activity

floor to about 70 km below the land. On this layer, all the continents and oceans are
situated. It contains all the things essential for life.

Let’s Recapitulate

Fill in the blanks with correct word.
1. Objects seen in sky are called _______________ (satellite/heavenly objects).

2. The moon and eight planets revolve around the _______________ (earth/sun).
3. Planets revolve around the sun in _______________ (orbit/eclipse).
4. The sun has a thin outer layer called _______________ (core/corona).

5. The middle layer of the earth is called _______________ (mantle/crust).
6. _______________ and helium gases are the major constituents of the sun.

Moon

Moon is the only natural satellite of earth. A satellite is an object which revolves around
a planet. There are two types of satellites –

1. Natural Satellites: These are naturally existing objects which revolve around

a planet.

2. Artificial Satellites: These are man-made satellites.

Moon revolves around the earth in an orbit at an average speed of 3683 km per hour. It
orbits at a distance of about 3,84,400 km from the earth. It moves slowest when it is at

furthest distant from earth and fastest when it is closest to the earth. The moon has a
diameter of 2000 miles (3476 km).
Factual Study
As moon reflects the sunlight falling on its surface, Moon is much closer to the
it shines in the sky. The moon has no light and earth as compared to the sun.
atmosphere of its own. Therefore, the day on the If a car has to travel so much

moon is very hot and the night is very cold. There distance at 95 km/hrs, it would
are a lot of craters on the surface of the moon. When take 5 months 15 days to reach
huge rocks hit the surface of the moon, meteorites the moon from earth.
are formed.

Landing on the Moon

The first man who landed on moon was Neil Armstrong, followed later by Edwin Aldrin
on 20th July 1969. They belonged to the American space mission Apollo 11.

90 Active Science-5