Science 5th primary 1st term unite 2 lesson 2

The Sun occupies the centre of the solar system and the Earth is one of the eight planets revolving around it.

The Earth is the planet that we live on, so we will study it in detail.Description of the Earth

Earth’s rotation around the Sun The Earth revolves around the Sun with the other planets by the action of gravity. The Earth completes one revolution around the Sun in 365.25 days.Earth’s location in the solar system The Earth occupies the third position according to its distance from the Sun. (It is preceded by Mercury and Venus).The distance between the Sun and the Earth is about 150 million kilometers.Earth’s shape It is spherical object which is about to be completely circular accompanied with: A slight flattening at the two poles.Indented outward at the equator.Where the tropical radius about 22 Km larger than the polar radius.Earth’s volume Concerning the volume, the Earth occupies the medium position in the solar system, where it occupies the fourth order regarding the volume because it is the biggest inner planet. Its average radius is about 6368 km.Earth’s mass It is considered the biggest in mass in the inner planets of the solar system.Its mass is 5.9×10 24 kilograms.

Characteristics of the planet Earth that support the continuity of life

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Science 5th primary 1st term unite 2 lesson 2

The atmosphere. The hydrosphereThe suitable temperature. The gravity. The suitable air pressure.

First: Earth’s atmosphere The Earth is surrounded by an atmosphere as it appears like a white Colour around the Earth in the picture captured from the moon’s surface.The Earth’s atmosphere consists of a group of gases that are shown in the following table

atmospheric air ratio

Oxygen 21%Nitrogen 78%Carbon dioxide 0.03 %Water vapour Veritable pervntage

* The importance of the Earth’s atmosphere :

1. It consists of very important gases which are: A. Oxygen gas: Its importance: It is used in respiration process of living organisms. It helps in combustion (burning) process of fuels.B. Nitrogen gas: Its importance: It lessens (reduces) the effect of oxygen gas during processes. Plants use it to form proteins. C. Carbon dioxide as: Its importance: 1-It is used by green plats n photosynthesis process to grow and produce food for other living organisms. 2- The great expansion of atmosphere in the space helps in: Burning millions of small falling meteors completely before reaching the earth’s surface. Reducing the high speed of large meteorites and burning a part of them before their hitting the earth’s surface.

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Science 5th primary 1st term unite 2 lesson 2

3. The weather ad climate phenomena that take place me the atmosphere such as: Wind movement. - Clouds formation.Rain falling to complete the water cycle.It participates in keeping the temperature suitable for the earth.It contains ozone layer which protects living organisms from the harmful ultraviolet rays.What will happen if the air contains only oxygen gas and is free of nitrogen gas?The combustion process will be fast and proceeds without any control.

Water is divided into : 1-Salty water: It represents 97 % of the water area o the water area on the earth’s surface. It exists in : Oceans * Seas 2- Fresh water: It represents 3% of the water area on the Earth’s surface. It exists in : Rivers * lakes * Snow at the two poles Ground water in the pores and cracks of the rocks that form the solid mass of the Earth’s crust.

* The importance of water to living organisms :

- Water is necessary for the life of all living organisms (plants, animals and human), Where:1. Plants use it in photosynthesis to from food. 2. Man and animal benefit from it on:Completing food digestion and absorption processes in the digestive system. Sharing in blood formation. Stabilizing the body temperature.Hydrosphere keeps the temperature on land during day and night within the proper limits for the living organisms. Hydrosphere makes a suitable environment for large numbers of living organisms, where more than 50% of known living organisms live in the aquatic environments.

Third : The suitable temperature :

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Science 5th primary 1st term unite 2 lesson 2

The temperature is suitable for the continuity of life of living organisms at day and night due to the Presence of the Earth in the third position according to its distance from the Sun.

Fourth: The gravity : The Earth has a force of gravity that makes the life possible through: Constancy and steadfastness of objects and living organisms on its surface.Steadfastness of the Hydrosphere position on its surface.Keeping the Earth surrounded by the atmosphere.

Fifth: The suitable air pressure : The Earth is characterized by the presence of suitable air pressure of about 76cm.Hg.This pressure suits the continuity of life on the Earth’s surface.G.R Planet Earth is suitable for life:Due to: - The presence of water The presence of atmospheric envelope containing oxygen gas which is needed for life. Its temperature is suitable during both day and night. Its atmospheric pressure and its gravitational force are suitable.

The inner structure of the Earth *The origin of the inner part of the Earth:The inner part of the Earth was in a molten form after the origin of the Earth due to the high temperature. As a result of the revolution of the Earth around the Sun and its axis and due to gravity:*The heaviest metals in density (iron and nickel) descended towards the center.*The lightest components in density ascended. This led to the formation of a number of layers. Each layer has its own characteristics that distinguish it from the others. The Earth (as the egg) consists of three layers. We can summarize the Earth’s layers from outside to inside in the following table:

Earth’s layers

Earth’s crust The mantle

The core

Formation: It is a relatively light outer layer.

It is a rocky layer.

It is a layer of molten

It is a solid in iron and nickel

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Science 5th primary 1st term unite 2 lesson 2

Thickness: Ranges between 8-50km

A bout 2885 km

About 2270 km.

About 1216km.

The earth's crust consists of group of different rocksThe earth's crust consists of two layers 1- Soil surface (superficial layer) A-it is fragmentedمفككه and loose B-its thickness is small صغير سمكها

C-it consists of mixture of mineral substance water air martial 2- Soil basis The lower layer beneath the soil represent consists of rocks G.R. The plant roots extend easily through the upper part of earth's crust?Because the upper part is fragmented and loose G.R. The plant roots can't extend through the lower part of earth's crust?Because the lower part consists of different types of rocks

The earth's rocksFirst: The igneous rocks :

The outer core of the earth contains molten metals which are called magma.When magma is extruded from (reaches) the Earth’s surfaceIn the form of volcano flows, it is called lavaWhen magma and lava cool and solidify, they from the igneous rocks.Magma: it is a very hot thick liquid underneath the Earth’s crust

Igneous rocksThey are rocks formed by solidification of the magma underneath theEarth’s crust or lava on the Earth’s surfaceIgneous rocks can be divided according to the site (place) of their formation in proportion to the Earth’s surface into two main divisions which are:A Plutonic rock. جوفية B surface or volcanic rocks. سطحية بركانية

A- Plutonic rocks:Ms. Marim 5

Science 5th primary 1st term unite 2 lesson 2

They are rocks that are formed inside the Earth’s crust at great depths.They are in the form of huge masses covering wide areas.They have coarse خشُن texture.

G.R. The crystals of minerals that form the plutonic igneous rocks are large-sized.

Because magma at depth gets cool slowly, therefore minerals take a longer time to crystallize so, their crystals are large-sized.

B Surface or volcanic rocks : They are the rocks that are formed when magmaReaches the Earth’s surface as it is extruded from volcanoes.They are in the form of a flow of lava.They have smooth texture.G.R. The crystals of minerals that form the volcanic rocks are small sized.Because the minerals that form them do not take the time required forCrystallization, where lava cools quickly on the surface, therefore their crystalsBecome small-sized.Volcanic rocks contain small circular holes.Due to the extruding of gases from volcanic flows during their cooling andFormation of rock. Examples : of igneous rocks : 1. Granite. 2. Basalt.

1 Granite : It is plutonic rock.Its colour is pink or grey. The minerals forming it are seen by the naked eye.It is heavy, rough, solid, cohesive and it isn’t easily broken.It exists in the Eastern Desert and Sinai Peninsula.The minerals that form the granite rockGranite rock consists of three main minerals which are:Quartz 2. Feldspar 3. Mica

1 . Quartz : It is silicon dioxide.It has a glassy luster.

2 Feldspar : It consists of aluminium silicate and other elements such as :

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Science 5th primary 1st term unite 2 lesson 2

Potassium, calcium or sodium.The colour of granite changes according to the type of feldspar.

3 Mica : It consists of thin bright sheets.Its colour is light (biotit)Or dark brown (muscotive).

2 Basalt : It is a volcanic rock.It is a dark coloured rock.Its components cannot be seen by the naked eye.It is formed by solidification of lava when it coolsOn the Earth’s surface.It is found in Egypt in Abou-Zabal, near Abou Rawash and El-Fayoum.

The minerals that form basalt rockBasalt rock consists of three main minerals which are :Olivine 2. Pyroxene 3. Feldspar

1 Olivine: It consists of magnesium and iron silicates.It is characterized by a green olive colour and it has a glassy luster.

2 Pyroxene : It consists of a mixture of calcium and iron silicates.It has a dark green colour and a prism shape.Comparison between granite rock and basalt rock:

Points of Comparison Graniteجرانيت rock Basalt بازلت rockKind : Igneous plutonic

rock. جوفية بلوتوني يةنار ةIgneous volcanic rock.

نارية بركانية

Colour: Pink or grey. Dark in colour.Components: Can be seen by naked

eye.Cannot be seen by naked eye.

Found in: Eastern Desert and Egypt in Abo-Zaabal, near

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Science 5th primary 1st term unite 2 lesson 2

Sinai Peninsula. Abou Rawash and El-Fayoum.

Minerals forming it:

Quartz, feldspar and mica.

Olivine, feldspar and pyroxene.

Second: The sedimentary rocks : They form a thin cover that wraps about 75% Of the surface of the Earth solid mass, although They represent 5% only of the total Volume of Earth’s crust rocks.

Formation of sedimentary rocks : The formation of sedimentary rocks takes place in three successive processes:Erosion (fragmentation) of the igneous, sedimentary or metamorphic rocks that previously existed.Transportation of the detritus (fragmented particles of rocks) by water current or by air where these particles are deposited.Sedimentation (deposition) of rock particles in an aqueous or an aerial medium, laterThese deposited particles adhere together forming the sedimentary rocks.

Activity 2 to show transportation and deposition processes :

Steps : Bring a rectangular basin and place it in an inclined position.Put a mixture of sand, shingle and gavel at its upper part.Pour water upon this mixture.Observation: Sand deposits at the lower part of the basin while shingle and gravel remain at its upper part.Conclusion: Water takes the smooth sand in its way and the sand deposits at the lower part, while shingle and gravel remain at the upper part.If the speed of water increases, the size of the transported grains increases.

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Science 5th primary 1st term unite 2 lesson 2

This represents what happens in rivers and seas and it produces sediments in the form of layers.N.B. The formation of sedimentary rocks undergoes three stages:1. Erosion. 2. Transportation. 3. Sedimentation.

الخليط هذا على الماء بصب وقم والزلط والحصى الرمال من خليطا اعالة فى وضع مائل بشكل وضعة الشكل مستطيل حوضا أحضر:- نشاط حجم زاد الماء سرعة زادت ولو أعاله فى تبقى والزلط والحصى الحوض أسفل فى وتترسب طريقها فى الناعمة الرمال المياه تأخذ:- الترسيب عند المالحظة طبقات صورة على رواسب عنة وينتج والبحار األنهار فى يحدث ما يماثل وهذا المنقولة الحبيباتالفتات حمل على والريح الجارية المياة قدرة تضعف عندما الترسيب ويحدث الجارية المياة و الرياح بفعل النقل يتم: االستنتاج

CitificationWhen the sediments of the bottom layers are exposed to high pressure resulted from the weights of the deposits above them. This causes a decrease in the ratioof water existing between the grains.As the pressure increases, more grains are deposited.By the time, the grains become solid and appear as layers above each other.The layers in the bottom are older and the above ones are more recent.

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