UNIDAD DIDÁCTICA.
INTRODUCTION:
This unit, The Hydrosphere is fundamentally concerned with the dynamics
associated with water and the hydrosphere. To examine in detail the important
movements of water on the planet and the impact of the water cycle on the Earth’s
surface should help the students to understand the relevance of water in nature.
DIDACTIC AIMS:
1. To know what the hydrosphere is.
2. To distinguish how the hydrosphere was formed
3. To describe the main characteristics and distribution of sea water and continental
water.
4. To obtain and organise information in tables, concept maps and diagrams.
5. To describe the water molecule.
6. To know the water’s properties.
7. To describe the water cycle and to analyse what causes it.
8. To know the main water uses.
9. To describe the main water’s pollutants
10. To distinguish between fresh water and potable water
11. To discover differences between water purification and water depuration
12. To develop a favourable attitude to the rational use of water as a natural
resource.
13. To know the specific vocabulary about the hydrosphere.
CONTENTS:
1. How did the hydrosphere form?
2. Why is there water on Earth?
3. Where is there water on Earth?
4. Why does a water molecule consist of?
5. What are the properties of water?
6. What is water cycle?
7. Water uses
8. Water pollution
9. Water purification
10. Depurated water
SEQUENCE OF LEARNING ACTIVITIES:
We will use different kinds of learning activities.
We will start the unit making a hydrosphere “quiz”, several sort questions to discover
the knowledge level of our students, in order to adapt the learning activities.
During the class students will make “development activities” which will help them to
acquire and practice the main concepts. The main types of development activities will
be:
– Close questions.
– Open questions.
– Summarize questions.
– Fill the gap question.
o About unit texts.
o About videos and songs.
– Mach with arrows.
– Label diagrams.
– Find information by your own (extension question).
– Read text and find information.
Simulation activities, that will be carry on the laboratory and will be oriented to
kinesthetic learning.
Computer’s activities that will be carry on the computer room.
DIDACTIC RESOURCES AND MATERIALS
Computer presentations.
Unit handout which contain texts, activities (charts, questions, exercises...)
Experimental model of water depuration (laboratory).
Graphics and tables.
Educational films (Bill Nye).
Songs about water cycle (Tom Glanzes and Bill Nye).
Water study (internet)
http://concurso.cnice.mec.es/cnice2005/63_el_agua/actividades/activ_ag2.html
SPACE AND TIME ORGANIZATION:
We will use different spaces, the group class, the laboratory and the computer room.
The class structure will be:
5 – 10 minutes of “Spanish quiz”. We will make sort questions related to the unit to
know the real knowledge acquire by our students.
15 – 20 minutes to teach using Power Point presentation.
15 – 20 minutes to make activities.
10 – 15 minutes to correct activities.
One class will be in the laboratory to develop the water depuration practice, another
class will be in the computer room to make the virtual water study.
ASSESSMENT:
To assess the knowledge obtained by our pupils we will use:
Activities correction.
Student’s compositions about water pollution.
Student’s workbooks revision.
Written tests.
Start class quiz.
Written exams.
Student’s behaviour.
Label diagrams about saving water.
Work in small groups.
UNIT: THE HYDROSPHERE
Our Earth is mostly water. Approximately 70% of the Earth’s surface is water and
30% of the Earth’s surface is land.
1. Draw the percentages of water and land in the circle.
2. Why do we say that our planet could be called “Water” instead Earth?
3. Where is there water on Earth?
How did the hydrosphere form?
The hydrosphere was formed on early Earth around 4.500 billion years ago
•
Because volcanic eruptions released water vapour into the air.
•
Comets and water-rich asteroids fell on the early Earth.
When the Earth got cold, water vapour in atmosphere turned into water and it rained
for a long time and the hydrosphere was formed.
4. Remember. Changes of state:
 From liquid state to a solid state:………………………………………………
 From liquid state to a gas state:…………………………………………………
 From gas state to a liquid state:…………………………………………………
 From solid state to a liquid state:…………………………………………………
5. Name the different states of water we can find in our planet?
6. From where did the water o Earth originate?
7. When was the hydrosphere formed?
Why is there water on Earth?
The Earth is the only planet in the Solar System in which water exist in the three
states. It is because:
•
The Earth is the right mass to hold the atmosphere.
If the mass was smaller, the Earth’s gravity would be lower and the atmosphere
would be lost.
•
The Earth is the right distance from the Sun.
If the distance was longer the Earth’s temperature would be lower and the water
would be ice.
If the distance was shorter the Earth’s temperature would be higher and the water
would be vapor.
8. Is there water in other parts of the Solar system?
9. Why does the Moon have no atmosphere?
10. Could a planet have a hydrosphere without an atmosphere?
11. In what state would the water be if the distance between the Sun and the Earth
was shorter?
12. Why is Mars’s water frozen?
13. Can you name planet without water or ice on its surface?
Where is there water on Earth?
There is salt water (97%) and fresh water (3%) on Earth.
Salt water:
Oceans, seas.
Fresh water:
Ice from glaciers or at the North and South pole.
Groundwater, water below the Earth surface.
Water in the atmosphere or in living things.
Surface fresh water.
Rivers
Lakes
14. Can you build a chart using these words?Ice, Oceans, Atmosphere water, Fresh
water, Rivers, Groundwater, Seas, Salt water, Lakes, Surface fresh water.
15. Match with arrows.
OCEAN
FRESH
RIVER
SOLID
LAKE
ICEBERG
SALTY
STREAM
LIQUID
RESERVOIR
SEA
16. Improve your vocabulary. Match every word with its definition
BOREHOLE, RESERVOIR, OCEAN, GLACIER
It’s similar to a lake but it’s not natural, it’s made by men. What is it?
It’s
It’s
a
type
a
of
hole
water
and
to
get
it
contains
underground
many
minerals.
water.
What
What
is
is
it?
it?
It’s similar to a river but it’s not made of liquid water, it’s made of ice. What is it?
17. Classify the following locations of continental water and marine water: river,
ocean, stream, lake, spring, sea, marsh, underground water, reservoir, swimming
pools, well, iceberg, glacier, and lagoon.
CONTINENTAL WATER
MARINE WATER
What does a water molecule consist of?
A water molecule (H2O) is made up of three atoms, one oxygen atom and two
hydrogen atoms.
18. Draw a water molecule.
What are the properties of water?
•
Water is a powerful solvent: It dissolves many components (rocks, salts)
•
Ice has less density than water: Ice floats over the water, and permits life during
winter.
•
Water absorbs heat: Water moderates the Earth climate, by absorbing heat in
summer and emitting heat in winter.
•
Water molecules have cohesion. Attraction between particles of water.
19. Why does ice float in water?
20. What does water do during summer?
21. Where do you think temperature is lower during the winter, in Cartagena or in
Caravaca?
22. Match with arrows.
It dissolves many components
Absorbs heat
Ice floats over the water
Powerful solvent
Water moderates the Earth’s climate
Molecules have cohesion
Attraction between particles of water
Less density than water
What is water cycle?
Water on Earth is continuously moving from one place and state to another. This
continuous movement is called the water cycle. The water cycle involves several
processes.
•
Evaporation: water changes from a liquid to a gas (vapor).
•
Condensation: Water changes from a gas (vapor) to a liquid. It forms clouds in the
sky.
•
Precipitation: any form of water that falls from clouds after condensation has
taken place.
•
Transpiration. Water from plants and animals evaporates into the atmosphere.
•
Ground runoff. Rain, melted snow, or other water that flows in underground
streams.
•
Surface runoff. Rain, melted snow, or other water that flows on the surface,
streams and rivers.
23. Could you define a water cycle?
24. What are the main processes in a water cycle?
25. Read the definitions, then label the water cycle diagram.
Drinking water.
The majority of freshwater (70%) is beyond our reach. only 0.3% of the freshwater is
available from rivers, lakes and reservoirs. For this reason the water is a scarce
resource.
Drinking water or potable water is water pure enough to be used without risk for our
health.
Freshwate
r
Readily accessible
freshwater
Groundwater
0.592%
Ice caps
and
glaciers
0.592%
0.014
%
Lakes
0.0007
%
Soil
moisture
0.0005%
Biota
0.0001
%
Rivers
0.0001
%
Atmospheric
water vapor
0.0001%
26. Do you remember what the percentage of freshwater in the Earth is?
What is potable water?
Did You Know?
The adult human body is about 50 to 65 percent water, whilst a child’s body is
about 75 percent water.
The human brain itself is 75 percent water.
While the human body can live for weeks without food, it can only survive a few
days without water.
Agriculture consumes 60 to 80 percent of the fresh water resources in most
countries, and as much as 90 percent in others.
Ninety percent of urban sewage in the developing world is discharged into rivers,
lakes, and coastal water-ways without any treatment.
27. How many buckets of water do you think are used every time you do one of the
following? (Every bucket contains 8 litres)
QUESTIONS
A) Have a bath?
B) Have a shower?
C) Flush the toilet?
D) Wash the dishes by hand?
E) Wash dishes using a dishwasher?
F) Use a garden hose for 1 hour?
G) Wash one load in the washing machine?
28. Calculate how water is much used in one day, one week and one year.
Water uses.
Water is used in different way. The main uses are:
Agriculture.
–
Industry.
–
Domestic use.
% of total water used
–
80
70
70%
60
50
40
30
22%
20
8%
10
0
Agriculture
Domestic
Industry
Water uses
Water Pollution
Water pollution is a change in water’s properties that has a harmful effect on people
or other living beings.
Let's look at some of them:
Waste’s water from industries and farmland.
Sewage water from towns and cities
Agricultural fertilizers and pesticides which filter into the soil and pollute rivers and
groundwater
Water purification
Water may contain dissolved salts and minerals, microbes, pollutants and insoluble
materials like sand and stones.
Water is treated to remove any harmful components before being used into the public
supply.
This is achieved is several ways:
Filtration.
Sedimentation.
Chlorination.
29. Write the correct word!
FILTRATION, SEDIMENTATION, CHLORATION
Chlorine gas, injected into the water, kills microbes.  …………………
The water is sprayed onto specially prepared layers of sand and gravel 
……………………
A chemical is added which causes tiny solid particles to clump together into larger
particles.  ………………………
Depurated water.
If wastewater was discharged directly to rivers and streams without treatment we
would contaminate the water. For this reason we have to treat polluted water to
remove any pollutants before pour it to rivers or seas.
30. Read the text.
We all need water to live. The Earth has a lot of water but most of the water is not
good for drinking. 97% of water is sea water and we can´t drink it because it’s salty;
we can’t use sea water for irrigation. 2% of water in the Earth is ice in the poles and
glaciers. Just 1% of the water in our planet is fresh water, liquid fresh water. In
addition, some countries have much more water than others. We live in a country
with little water because our climate is dry. So we have to save water.
31. We want to encourage people in the school to be careful with water. Write three
slogans to get it.
Miguel Ángel Ruano Calvo