2 for moving objects:



2 for moving objects:

According to the speed by which the object moves, the state of the object can be divided into:

A. Object move with regular speed

- The car moves equal distances every one second in certain direction.

|Displacement (m) |10 |20 |30 |40 |50 |

|Time(sec.) |1 |2 |3 |4 |5 |

B. Objects move with irregular speed

- The car moves unequal distances every one second in certain direction.

|Displacement (m) |5 |9 |20 |35 |55 |

|Time(sec.) |1 |2 |3 |4 |5 |

N.B.

• The speed can be defined as follows

The speed is the displacement covered by an object in one second.

• Point of origin is the point where the two axes are intersected.

EX: The opposite graph represents the motion of a body:

1. Mention the kind of the motion of this body. Why?

2. Calculate the distance covered by this body after 3 seconds and 5 second.

Answer:

1. It moves with regular speeds.

Because the displacements covered by the body every second equal.

2. Distance after: 3 seconds is 60 meters.

5 seconds is 100 meters.

Lesson 1 celestial bodies

- The celestial body is anybody swims in the space such as stars, planets, moons and rocky or gaseous bodies.

- All celestial are in a permanent motion according to the will of Allah.

Stars: - When you look at the sky in a clear maples night, you will see a huge number of bright bodies called “Stars”

Stars

They are big-sized bodies emit enormous amounts of heat and light.

- Stars appear small although they are big-sized, because they are millions of kilometers away from us.

- The dist between the stars are very large, so astronomers don’t measure them by kilometers, but with the “ Light year”

Light year

It is the distance covered by light in one year and it equals 9.467* 10 12 km.

What is meant by: The distance between the Sun and a star is three light years?

This means that the distance between the sun and this star = 3*9.467*1012

28.401*1012km.

Ex: Calculate the distance in light year between two stars, if the distance between them equals 37.868*1012km.

Distance = 37.868*1012/ 9.467*1012 = 4 light years

Star form groups called “Galaxies”

Galaxies

• They are the grand (bigger) units forming this universe.

• They are a tremendous collection of stars.

• They are system that consists of thousands of millions of stars.

The galaxy system that our Solar system belongs to it is known as “the way of chopped hay” galaxy or “The milky way galaxy”

- Milky Way galaxy takes an oval shape with coiled spiral arms extend from it, the sun lies on one of these spiral arms.

Solar System

Through the astronomical expedition, astronomers knew the solar system.

The sun

- It is the star of our solar system

- It is the biggest body in the solar system

- The planets

- - They are eight spherical opaque bodies revolve around the sun in one direction ( counter clock wise)

- They revolve around the sun in semi- circular or elliptical (oval) paths (orbits).

- The paths of planets lie in one plane perpendicular to the Sun’s axis of rotation rotation around itself

The planets of the solar system are divided into two groups according to their distances from the Sun:

A. The inner planets group (the nearest to the Sun).

B. The outer planets group (The farthest planets from the Sun).

A- The small or inner planets group

- They are the nearest four planets to the Sun in the solar system.

- They are arranged according to their distances from the Sun (begin from the nearest) as follows: Mercury, Venus, Earth and Mars.

Characteristics of the inner planets:

1. They are small bodies, so they are called small planets.

2. They have a solid surface. (all of them have an atmosphere except Mercury).

3. Their densities are high (ranging between 3.3 to 5.5 gm/cm.3)

4. They have a few numbers of moons rotating around them except Mercury and Venus which have no moons.

Notice

- Earth is the planet that we live on it and it is the highest density in the inner planets.

- The nearest two planets to the Earth are Venus and Mars?

B- The big or outer planets group

- They are the farthest four planets from the Sun in the solar system.

- They are arranged according to their distances from the Sun (begin from the nearest) as follows: Jupiter, Saturn, Uranus and Neptune.

Characteristics of the outer planets:

1- They are big so they are called giant planets.

2-they are gaseous bodies that are formed of gaseous elements (the most important of them are the hydrogen and helium).

- Hydrogen gas is present in a solid state on the surface of outer planets due to the high pressure and extreme coldness on the surfaces of these planets.

3- Their densities are low (ranging from 0.7to 1.3gm/cm)

Because they consist of gaseous elements.

4-They have large number of moons rotating around each of them.

The difference of Gravity force on the planets, surfaces

• Isaac Newton attributed the falling of an apple on his head to the gravitational force of the Earth (which causes the Falling of that apple)

• Then he proved that there is attraction force among objects in the space depends on:

1. The mass of each object.

2. The distance between them.

- So, the planets revolve around the Sun in fixed orbits by the action of the Sun s gravitational force on them .

- The gravitational force on the surface of the planets are variable as shown in the following table :

|Planet |No. of Moons |

|Mercury |- |

|Venus |- |

|Earth |1 |

|Mars |2 |

|Jupiter |22 |

|Saturn |60 |

|Uranus |27 |

|Neptune |12 |

- They are celestial bodies of thousands of different sized rocky masses that rotate around the Sun in a certain region called “the belt of the wanderer asteroids " which lies between the orbits of mars and Jupiter .

The belt of the Wander asteroids

It is a region separates the group of the inner planets from the group of the outer planets.

When small rocky masses fall within the atmosphere of the Earth, they could burn up completely as a result of the heat produced from their friction with air forming luminous arrows in the sky.

These objects are called meteors.

Meteors can be seen with the naked eye at the clear nights.

When large rocky masses Fall within the atmosphere of the Earth and did not burn up completely, some parts of them which are called meteorites reach to the Earth s surface.

- The biggest meteorite till now has a mass of 80 tons and exists at the southern west of Africa.

-They are masses of rocks, ice and solidified gases.

- They revolve around the Sun in more elongated elliptical orbits intersecting with the orbits of the planets.

- The comet consists of two parts which are:

1- The head It contains:

• Icy spheres which are a mixture of solidified gases (carbon dioxide nitrogen and methane gases).

• Rocky parts.

• Dust and water molecules.

2- The tail it is considered a gaseous cloud.

- The most famous comet is Hilly which completes its revolution around the Sun each 76 years.

- Astronomers discovered the celestial by instruments called Telescopes

The Function of telescope

- It is used in identifying the celestial bodies.

The Kinds of telescopes

• Reflecting telescope Refracting telescope.

The Earth

• You learned in the previous lesson that 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

1. The atmosphere.

2. The hydrosphere.

3. The suitable temperature.

4. The gravity.

5. 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

The major component of the atmosphere is the nitrogen gas.

*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:

- 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.

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.

Question

- 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 :

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:

1. Constancy and steadfastness of objects and living organisms on its surface.

2. Steadfastness of the Hydrosphere position on its surface.

3. 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 |It is a rocky |It is a layer of |It is a solid in iron and |

| |outer layer. |layer. |molten |nickel |

|Thickness: |Ranges between 8-50km |A bout 2885 km |About 2270 km. |About 1216km. |

First: The igneous rocks:

You know from the previous lesson, the outer core of the

Earth contains molten metals which are called magma.

When magma is extruded from (reaches) the Earth’s surface

In the form of volcano flows, it is called lava

When 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 rocks

They are rocks formed by solidification of the magma underneath the

Earth’s crust or lava on the Earth’s surface

Igneous 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. B surface or volcanic rocks.

Plutonic rocks:

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 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 magma

Reaches 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 for

Crystallization, where lava cools quickly on the surface, therefore their crystals

Become small-sized.

Volcanic rocks contain small circular holes.

Due to the extruding of gases from volcanic flows during their cooling and

Formation 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 rock

Granite rock consists of three main minerals which are:

1. 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 :

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 cools

On the Earth’s surface.

It is found in Egypt in Abou-Zabal, near Abou Rawash and El-Fayoum.

The minerals that form basalt rock

Basalt rock consists of three main minerals which are :

1. 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 |Granite rock |Basalt rock |

|Comparison | | |

|Kind : |Igneous plutonic rock. |Igneous volcanic rock. |

|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 Sinai Peninsula. |Egypt in Abo-Zaabal, near Abou Rawash and |

| | |El-Fayoum. |

|Minerals forming it: |Quartz, ffeldspar 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:

1. Erosion (fragmentation) of the igneous, sedimentary or metamorphic rocks that previously existed.

2. Transportation of the detritus (fragmented particles of rocks) by water current or by air where these particles are deposited.

3. Sedimentation (deposition) of rock particles in an aqueous or an aerial medium, later

4. These 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.

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.

Citification

When 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.

-----------------------

- Jupiter is the biggest planet in the solar system.

-Mercury is the nearest planet to the Sun , while Neptune is the Farthest one from the sun. Import.

Notice

Notice

- Saturn planet has the large number of moons revolving around it.

Asteroids

Meteors

Meteors

They are luminous arrows that can be seen in the sky.

N.B.

Meteorites:

Meteorites:

The remaining part of the rocky masses without burning that falls on the surface

Of the Earth.

Comets:

Discovering the celestial bodies

Lesson 2

N.B.

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