BIOGEOSPHERE
Bilingual Biology and Geology
I.E.S. "J.S.Elcano (Sanlúcar Bda.)
1. Composition and structure
The atmosphere is the gaseous outer layer that surrounds the Earth.
a) Composition
The Earth's atmosphere is a mixture of gases called air.
Air is composed by:
- 78 % Nitrogen (N2)
- 21% Oxygen (O2)
- 0.03% Carbon dioxide (CO2)
- 0.97% other gases (water vapour,
Argon, etc)
The atmosphere was very different 4,600 million years ago.
The primitive atmosphere was made up of water vapour, carbon dioxide, nitrogen, hydrogen, ammonia and methane and it did not have oxygen.
The first living beings (bacteria) produced oxygen by photosynthesis.
It provoked a change in the atmosphere’s composition 2,000 million years ago to become what it is nowadays.
b) Structure
The atmosphere has four main layers. The separation in layers is caused by variation in temperature with respect to altitude.
- Troposphere
This is the nearest layer to the Earth.
The temperature decreases
from 15ºC to -50ºC
It is about 12 km thick.
It contains 80% of the air
in the atmosphere.
Meteorogical phenomena occur here.
The upper limit of this layer is called
Tropopause.
- Stratosphere
The temperature increases
from -50ºC to 0ºC.
It goes from 12 km up to 50 km.
It includes the ozone layer,
which absorbs the ultraviolet radiation.
The upper limit of this layer is called
Stratopause.
- Mesosphere
The temperature decreases
from 0ºC to -100ºC.
It goes from 50 km up to 80 km in height.
Here is where most meteors burn up
upon entry (shooting stars).
The upper limit of this layer is called Mesopause.
- Thermosphere
It is also called ionosphere.
The temperature increases
from -100ºC to more than 1000ºC.
This layer does not contain many gases.
It absorbs infrared radiation and other very harmful radiation from the Sun and reflects radio and television waves
back to the Earth
Here aurora borealis takes place.
READING ACTIVITIES
After reading the text, copy and answer the following questions into your notebook:
Remember: you must make complete sentences.
1.1. Copy and complete, with the information of the text, the following
chart about the layers of the Earth's atmosphere.
Then, listen and indicate to which layer each characteristic belong.
|
Layer of the atmosphere |
Temperature variation (ºC) |
Thickness (km) |
Name of its upper limit |
Important events that occurs here |
|
Troposphere |
||||
|
Ozone layer (absorbs the ultraviolet radiation) |
||||
|
From 0ºC to -100ºC |
||||
|
From 80 km upward |
||||
|
|
||||
1.2. Answer these questions about the atmosphere:
a. Which is the closest atmosphere's layer to the Earth? And the farthest one?
b. Which layer reflects the radio and television waves back to the Earth?
c. Where do the meteorogical phenomena take place?
d. Where is the ultraviolet radiation absorbed? And the infrared radiation?
1.3. Listen and identify the atmospheric gas that is described:
a. Nitrogen
b. Oxygen
c. Carbon dioxide
d. Water vapour
Now,
check
your
answers!
LISTENING ACTIVITIES
Download this worksheet
and complete it,
while you listen this audio.
SPEAKING ACTIVITIES
Now, in turns with your partner,
answer the questions in the worksheet.
(Diccionario Ing-Esp)
(Juegos de vocabulario)
(Visual dictionary)
(Visual dictionary)
(Glosario de C. Naturales)
(Science audio-glossary)
(Science audio-glossary)
(Pronunciación)
(Enciclopedia de C. Naturales)
(Tabla periódica)
Eva Mª
López Rodríguez
Departamento
Biología y Geología
IES " J. S. Elcano"
Sanlúcar de Barrameda