Download Science 2nd prep 1st term unit 2 lesson 1 part 2 Troposphere is the

Science 2nd prep 1st term unit 2 lesson 1 part 2
Layers of atomospheric envelope
Troposphere
Mesosphere
Stratoshpere
Thermosphere
First layer: Troposphere
Troposphere is the frst layer of the atmosphere. It means the disturbed layer where
most of the weather changes occur in this layer.
Characteristics and importance of the troposphere:
1-It extends 13 km above sea level to the tropopause.
2-As we go up, the temperature decreases by a rate of
6.5 ºC per 1 km until it reaches the lowest value of about
(-60 ºC) at tropopause.
3-Atmospheric pressures decreases as we go higher,
where it reaches about 0.1 of the normal pressure at sea
level.
4-It contains about 75% of the atmosphere mass.This
explains why all atmospheric phenomena like rain, wind,
clouds …. that forms the weather conditions, and
consequently up the climate
5-It contains about 99% of the atmospheric water vapour, which organizes the earth’s
temperature.
6-The air movement in this layer is vertical as the warm air currents go up and the cold
currents go down.
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Ms. Marim
Science 2nd prep 1st term unit 2 lesson 1 part 2
Exercise
If the temperature at the base of Mount Everest is 20.6 ºC, how much is the temperature at its
top if the mountain height is 8862 m?
Solution:
Height (km) =8.862 km
The decrease in temperature = height (Km) v 6.5 = 6.5 ×8.862=57.603 ºC
Temperature at the top = temperature at the base – decrease in temperatur
=57.603 - 20.6= -37.003 ºC
Sceond layer: Stratosphere
Stratosphere is the second atmospheric layer, which is also called ozone atmosphere
Characteristics &importance of stratosphere:
1-It extends from tropopause (13 km above sea level)
to the stratopause (50 km) with thickness of 37 km.
2-At the lower part, the temperature is constant and
measure (– 60º C), then increases gradually until it
reaches 0º C at the end of the layer.
- This is due to the absorption of ultraviolet radiation
(emitted from The Sun) by the ozone layer that is present in the upper part of the layer.
3-The atmospheric pressure decreases on going higher where it reaches 1 mb.
4-It contains most of the atmospheric ozone which is concentrated between 20 - 40 km above
sea level.
5-lower part does not contain clouds or suffer from any weather disturbances.
The air moves in this part horizontally, making it suitable for fying planes
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Ms. Marim
Science 2nd prep 1st term unit 2 lesson 1 part 2
Third layer: Mesosphere
– Mesosphere is the third atmospheric layer.
– It means the middle layer. It is the coldest layer.
Characteristics and importance of the
mesosphere:
1-It is extended from the stratopause (50 km above
sea level) to the mesopause with thickness of about 35
km.
2-Temperature decreases with height rate until
reaches (– 90º C) at its end.
3-This layer is much vacuumed as it contains only a limited amount of helium and hydrogen
gases.
4-Meteors are formed in this layer and burnt due to friction with air molecules
Mesosphere layer is highly rarefied?
Because it contains limited quantities of helium and hydrogen gases only.
Fourth layer : Thermosphere
Thermosphere is the fourth atmospheric layer.
It means the heated layer as it is the hottest layer of the atmosphere.
characteristics and importance of the thermosphere :
1-It extends from the mesopause to 675 km above sea level with a thickness of about 590 km.
2-Temperatures increase rapidly with going higher until it reaches about 1200º C.
3-Its upper part contains charged ions. The distribution of the charged ions extends until 700
km above sea level; in a part known as ionosphere.
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Ms. Marim
Science 2nd prep 1st term unit 2 lesson 1 part 2
Ionosphere layer
It is a layer that contains charged ions and it has an important role in
wireless communications.
- Ionosphere plays an important role in wireless communication as it
refects radio waves transmitted by radio stations.
-it is surrounded by two magnetic belts known as Van Allen Belts, These two belts play an
important role in dispersing the harmful charged cosmic radiation away from the Earth. This
scattering causes the occurrence of Aurora phenomenon.
Van-Allen
belts:
They are two magnetic belts surrounding ionosphere and play an important role in scattering of
harmful charged cosmic radiations.
Aurora phenomenon:
It is a phenomenon that appears as brightly coloured light curtains seen from the both poles of the
earth.
Exosphere layer:
This is the area where satellites float around the Earth and transmit weather
condition information and TV prvograms.
* The Egyptian Satellite (Nile sat) transmits a number of different
educational channels that you can watch on digital space channels.
Exosphere:
It is a region in which the atmospheric envelope is inserted with outer space.
Ionosphere is very important in wireless communications?
Because it reflects radio waves transmitted by radio stations and communication centers.
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Ms. Marim
Science 2nd prep 1st term unit 2 lesson 1 part 2
The harmful charged cosmic radioations are scattered away from the earth before entering
ionosphere layers?
Due to the presence of Van-Allen belts.
Comparison between the layers of atmospheric envelope
Points
Troposphere
Stratosphere
Mesosphere
Thermosphere
Thickness:
13 kilometers
37 km
35 km
590 km
Temperature
- 60 at its top
-60 to 0 ºC
-90 at its top
1200 ºC at its top
Pressure:
100 mb
1 mb
0.01 mb
It contains:
75% of atmospheric Most of ozone gas
mass.
99% of atmospheric
water vapour
Air movement:
Vertically
Limited quantities
of helium and
hydrogen only
Charged ions in its
upper part.
Horizontally
Questions on lesson
Complete the following statements:
1 – troposphere contains about …………………% from atmospheric envelope mass and about ……………..
% from atmospheric water vapour.
2 – air movement is troposphere is …………………. , where hot air currents move ……………………. While
cold air currents move …………………………
3 – the stratosphere exteds with a thickness equals ……………. Km
4 – in the upper part of stratosphere, ………………… layer is found which absorbs …………….. rays
emitted from the sun.
5 – the atmospheric pressure in stratosphere layer …………… as we go up till it becomes
…………………. Of the normal pressure.
6 – pilots prefer to fly their planes in the ………………. Part of stratosphere due to the absence of
………………………… and turbulences.
7 - …………………… is the third layer in atmospheric envelope and its thickness is about ……………..
8 – mesosphere layer is highly rarefied because it contains limited quantites of ……………. And
…………………. Gases only.
9 - …………….. is the fourth layer in atmospheric envelope and also it is called …………………… layer
because it is the hottest layer in the atmospheric envelope.
10 – the temperature of thermosphere layer …………… as we go up until it reaches …………….. ºC
11 – the upper part of themospher layer is called ………………….. and it extends up to ………… km
above sea level .
12 – the highest temperature layer in the atomsphere is ………….. and the least one is ……………..
13 – ionosphere is surrounded by two magnetic belts known as ……………….. belts.
14 - ………………….. phenomenon appears as brightly coloured light curtains seen from the two
………………………. Of the earth.
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Ms. Marim
Science 2nd prep 1st term unit 2 lesson 1 part 2
15 – most of weather features occur in …………………. Layer. Whereas satellites swim through the
……………………… layer.
Chose the correct answer :
1 – all the atmospheric phenomena on the earth like rains, winds , clouds take place in …………
layer.
a. mesosphere
b. stratosphere
c. thermosphere
d. troposphere.
2 – water vapour in troposphere ………………….. the temperature on the earth.
a. organize
b. decreases
c. increases
d. has no effect.
3 - …………….. is the region between stratosphere and mesosphere.
a. thermopause.
b. mesopause
c. stratopause.
4 – ozone layer is found in ……………… layer.
a. troposphere
b. stratosphere
c. mesosphere
5 – the air moves ………………….. in the stratosphere layer.
a. horizontally
b. vertically
c. inclined
d. tropopause
d. thermosphere
d. no correct answer.
6 – the coldest atmospheric layer in the atmospheric envelope is ……………………
a. troposphere
b. stratosphere
c.mesosphere
d. thermosphere.
7 – the thickness of mesosphere layer is ………… km
a. 1000
b. 13
c. 37
d.35
8 – the temperature at the top of mesosphere layer reaches ……………..
a. 76
b. – 90
c. – 60
d. 1200
9 – the ………………. Layer is much vacuumed layer.
a. troposphere
b.stratosphere
c. mesosphere
d. thermosphere
10 – luminous meteors are formed in …………….. layer.
a. ionosphere
b. stratosphere
c. mesosphere
d. exosphere.
11 – the hottest atmospheric layer in atmospheric envelope is ………………..
a.troposphere.
b. stratosphere
c. thermosphere
d. mesosphere.
12 – ionosphere layer is located in the upper part of …………….. layer.
a. stratosphere
b. troposphere
c. mesosphere
d. thermosphere
13 – the charged cosmic radiations are dispersed in the ……………. Layer.
a. troposphere
b. stratosphere
c. mesosphere
d. ionosphere.
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Ms. Marim
Science 2nd prep 1st term unit 2 lesson 1 part 2
Write the scienctific term:
1 – the region between mesosphere and thermosphere.
2 – an atmospheric layer in which air moves horizontally
3 – the hottest atmospheric layer.
4 – two magnetic belts that help in scattering of harmful cosmic radiations away from
the earth.
5 – a phenomenon htat appears as brightly coloured light curtains seen from the both
poles of the earth.
6 – the region in which the atmospheric envelope is inserted with outer space.
7 – the region in which satellites orbit aournd the earth planet.
Give reasons for:
1 – the temperature is high in the upper part of stratosphere layer.
………………………………………………………………………………………………………………………………….
2 – stratspere layer is important for man's life.
…………………………………………………………………………………………………………………………………..
3 – the lower part of stratosphere is suitable for flying airplanes.
………………………………………………………………………………………………………………………………….
4 – mesosphere is the coldest layer.
………………………………………………………………………………………………………………………………..
5 – the upper part of thermosphere layer is called ionosphere.
………………………………………………………………………………………………………………………………..
6 – ionosphere is important for radio stations.
………………………………………………………………………………………………………………………………..
7 – occurrence of aurora phenomenon.
………………………………………………………………………………………………………………………………..
Compare between:
1 – Mesosphere and thermosphere
Concerning: temperature, importance and atmospheric pressure.
2 - Troposphere and stratosphere layers.
Write brief notes on the relation between rising abouve sea level and atmospheric
pressure.
** in one of the earth areas, we watch bright light curtains in the sky:
1 – what is this phenomenon called?
2 – whydoes this phenomenon happen?
3 – where do we can see this phenomenon?
** what is the similarity between the ionosphere and the house wall?!!
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Ms. Marim