Planet Earth: The Surface of the Earth

Question 1

What do we call the hard, rocky layer on the surface of the earth?

Answer 1

The earth’s crust.

Question 2

True or False. The earth’s crust stops at the sea.

Answer 2

False. The crust surrounds the whole earth, including under the sea and oceans.

Question 3

What is the earth made from?

Answer 3

Rock. Even under the soil, water, sand there is always rock.

Question 4

What four things things does life on earth need to survive?

Answer 4

Soil
Water
Air
Sunlight

Question 5

What is the top layer of the earth called? Describe it.

Answer 5

Topsoil.
Dark in colour.
And it has the remains of dead plants and animals in it.
Must nutrient rich layer.

Question 6

What is the second layer of the earth called? Describe it.

Answer 6

Subsoil.
Under the topsoil.
Not as nutrient rich as topsoil.
Nutrients go to this layer when it rains.

Question 7

What is decompose?

Answer 7

When a plant or animal dies and it breaks down into smaller parts and the nutrients go into the soil.

Question 8

What is below subsoil?

Answer 8

Broken pieces of rock mixed with some soil.

Question 9

What are the layers of soil?

Answer 9

Topsoil
Subsoil
Pieces of rock and soil (sandy soil)
Solid rock/crust (bedrock)

Question 10

Name two ways rocks are broken into tiny pieces of grain to make topsoil?

Answer 10

Root of plants growing in the cracks in the rock can split the rock.
Chemicals in the water and air cause the rock to weaken and crumble,

Question 11

What is fertile soil?

Answer 11

Soil in which the plants can grow well.

Question 12

Name three types of soil?

Answer 12

Sandy soil.
Clayey soil.
Loamy soil.

Question 13

Does coarse grain have large or small grains?

Answer 13

Large.

Question 14

What size are fine grains?

Answer 14

Very small.

Question 15

What are soil grains?

Answer 15

Small pieces of broken rock.

Question 16

What is humus?

Answer 16

Dark material in the soil made of fully decomposed remains of plants and animals.

Question 17

Describe sandy soil:

Answer 17

More coarse grains than fine grains.

Feels gritty when you rub it between your fingers.

Question 18

Describe clayey soil:

Answer 18

More fine grains than course grains.
If feels smooth when you rub it between your fingers.
Feel sticky when wet.

Question 19

Describe loamy soil:

Answer 19

Equal amounts of a sandy and clayey soil.

Contain humus.

Question 20

What is the difference between compost and humus?

Answer 20

In compost not all the vegetable and plant matter is fully decomposed. In humus it is full decomposed.

Question 21

True or false. Can soil hold air and water?

Answer 21

True.

Question 22

Why is loamy soil the best soil for growing plants?

Answer 22

It has a mixture of coarse and fine grains. It does not get too wet or too dry.

Question 23

Name four kinds of mals that live in soil.

Answer 23

Earthworms
Termites
Crickets
Spiders

Question 24

What do animals that live in soil help with?

Answer 24

Mixing the soil up so that it takes material on the top into the soil.
They make open spaces for more air and water so that it makes it easier for plants to grow.

Question 25

What is soil erosion?

Answer 25

When the soil is washed away by water or blown away by wind.

Question 26

How long does topsoil take to form?

Answer 26

Many thousands of years.