YEAR 7 SCIENCE HOMEWORK –1 /PLANET EARTH & SOLAR SYSTEM
THE SPHERES
 COMPREHENSION: Read and answer the questions below.
Read and answer the questions below in single complete sentences
 The lithosphere is the outside layer of the Earth. It consists of pieces of crust,
called plates, which move very slowly over the surface of the Earth. The
lithosphere is made of solid rock. The continents are part of these plates.
 The asthenosphere is the part of the Earth which moves the plates. It is the
bottom of the crust and the top of the mantle. It is slowly moving. It provides
the driving force that pushes the plates over the surface of the Earth.
 The atmosphere is the layer of gases around the Earth. These gases are what
we call air. The atmosphere is densest at the surface of the Earth, and gets
thinner as you go higher.
 The biosphere is the layer inhabited by living things. It extends deep
underground where newly discovered bacteria live, into the deepest parts of
the oceans, and many kilometres up in the atmosphere.
 The hydrosphere is the layer of water around the Earth. It is the oceans, but
also includes the water in the ground and rocks, and the vapour and ice high in
the sky.
1. What does the lithosphere consist of?
2. Describe the role of asthenosphere.
3. Describe the density of atmosphere.
4. Describe the size of biosphere.
5. Describe hydrosphere.
 QUIZ: Write True or False next to numbers 1 to 5
1. Pieces of crust are known as plates.___________
2. Asthenosphere is located at the bottom of mantle.___________
3. The gases in atmosphere are known as air.____________
4. Living things only exist on the surface of the Earth.____________
5. Snow on top of Mount Everest is an example of
hydrosphere._____________
Paste this homework sheet in your science book.