The document discusses the properties and states of water, explaining that water is essential to life on Earth and can be found naturally in its solid, liquid, and gas forms. It moves continuously through the hydrologic cycle of evaporation, precipitation, and flow towards the oceans due to solar energy and gravity. Proper management of water resources is needed to ensure a sustainable supply of fresh water for all uses including human consumption, agriculture, industry, and recreation.

1. UNIT: 6.- LA HIDROSFERA
EL AGUA ES UNA SUSTANCIA ASOMBROSA.
• El agua: Es una sustancia muy común en la Tierra y en otros lugares del Universo. En la tierra es la única sustancia
que se encuentra en los tres estados de forma natural.
Es un compuesto químico formado por moléculas. Cada molécula está formada por dos átomos de hidrógeno y un
átomo de oxígeno (H2O).
La forma y la naturaleza de su molécula le dan al agua propiedades asombrosas:
- Al bajar la temperatura de 4 ºC a 0 ºC, el agua se dilata (lo contrario que las demás sustancias). Esto hace que
cuando se congela (a los 0 ºC), la densidad disminuye.
- El agua congelada, al tener menos densidad, flota en el agua líquida. Gracias a esto, en ríos, lagos y mares, los
peces pueden vivir en invierno aunque la superficie esté congelada.
PROPIEDADES DEL AGUA.
• El agua como disolvente: El agua es el mejor disolvente conocido. Lo disuelve casi todo, menos las grasas.
• Salinidad del agua: El agua puede disolver sales minerales, la cantidad de sales minerales disuelta en agua se llama
salinidad.
- Agua dulce: Se llama agua dulce si contiene menos de un 1 % de sales disuelta.
- Agua salada: Se llama agua salada si contiene más de un 1 % de sales disuelta.
• Propiedades térmicas del agua: El agua necesita mucho calor para que su temperatura aumente, pero también pierde
calor muy despacio (las demás sustancias pierden calor más rápidamente).
LOS ESTADOS DEL AGUA.
• El agua en estado líquido: La mayor parte del agua de la Tierra está en estado líquido.
El agua líquida se encuentra en:
- Océanos y mares: están formados por agua salada y cubre las tres cuartas partes de la superficie de la Tierra.
- Aguas continentales: están formadas generalmente por agua dulce. La encontramos en: ríos, lagos, arroyos,
torrentes, lagunas, charcas, pozos, aguas subterráneas, etc.
- Las nubes: están formadas por acumulaciones de pequeñísimas gotas de agua dulce.
• Agua en estado gaseoso: Es una mínima parte del total y forma parte de la atmósfera.
• Agua en estado sólido: La mayor parte del agua en estado sólido se concentra en las regiones polares. El resto está en
zonas muy frías, como las cumbres de las montañas.
Se distribuye así:
- Las banquisas polares: son las capas de hielo que cubren los océanos Ártico y Antártico (en los Polos Norte y
Sur).
- Los glaciares: son grandes masas de hielo, acumuladas sobre la Tierra.
EL CICLO DEL AGUA.
• Ciclo del agua: La energía del Sol y la gravedad hacen que el agua de la Tierra esté en continuo movimiento.
Tiene tres grandes etapas:
1.- El agua pasa a la atmósfera: la energía del Sol calienta el agua de océanos, mares, ríos, lagos, etc. El agua se
evapora y pasa a la atmósfera.
Los seres vivos con su
transpiración también transmiten
agua a la atmósfera.
2.- El agua vuelve a la superficie
terrestre: Al llegar a las capas altas
y frías de la troposfera, el vapor de
agua se enfría y se condensa. Se
forman las nubes y el viento las
desplaza.
En determinadas condiciones, el
agua cae en forma de lluvia, nieve o
granizo.
3.- El agua circula por la corteza
terrestre: La gravedad terrestre
hace que el agua se desplace hacia
abajo. Se forman: torrentes, arroyos,
ríos, etc. hasta llegar a lagos, mares u
océanos.
Parte de esta agua se infiltra y
forma las aguas subterráneas.

2. USOS DEL AGUA.
• ¿Para qué usamos el agua?: El consumo de agua se ha incrementado alarmantemente.
La usamos para:
- Satisfacer las necesidades básicas: alimentación, higiene, etc. (unos 5 litros diarios por
persona).
- Mejorar nuestra calidad de vida: lavar, limpiar, etc. (unos 80 litros diarios por persona).
- Generar riqueza: agricultura, industria, transporte, etc. (unos 3.200 litros diarios por
persona).
- Actividades recreativas: mantenimiento de instalaciones, etc.
Para la mayor parte de estas actividades se necesita agua potable. El agua potable es una
pequeñísima parte del agua terrestre (el 2,5 %).
DESTRUIMOS LA HIDROSFERA.
• Contaminación de las aguas: Es cualquier alteración de las propiedades del agua que puede
perjudicar nuestra salud y la de los demás seres vivos. Esta contaminación se puede producir por
vertidos de aguas residuales, vertidos de sustancias químicas, metales, plásticos, pilas, etc.
• Agotamiento de las reservas: Si consumimos el agua a un ritmo mayor al de su regeneración.
• Modificación del entorno: Grandes construcciones como presas, embalses o carreteras pueden
modificar profundamente el paisaje.
GESTIÓN DEL AGUA.
• Agua de calidad para todos: Debemos vigilar la calidad de las aguas y comprometernos en su
cuidado:
- En ríos, lagos, embalses, aguas subterráneas, etc. debemos evitar arrojar sustancias
contaminantes y no debemos transformar los cauces naturales.
- Ahorro de agua sobre todo en la agricultura, industrias y en los hogares.
- Depurar y reutilizar las aguas, para ello debemos depurar el agua de las ciudades antes de
verterla sobre ríos o mares, o utilizarla para riego o limpieza de las calles.
• Medidas para gestión sostenible del agua:
1.- Extracción racional: Es decir coger el agua en épocas de abundancia y almacenarla para las
épocas de escasez.
2.- Tratamiento y distribución: Para que llegue a todos los puntos en cantidad suficiente y en las
condiciones adecuadas.
3.- Reducción del consumo: Por medio de ahorro en agricultura, industria y en nuestros hogares.
4.- Depuración de las aguas residuales: Para que se puedan reutilizar o ser vertida a la naturaleza
sin que peligre la salud de las personas ni de los ecosistemas.

3. NAME: _________________________________________ DATE: ________ 1º ESO ___ (Bilingual)
UNIT: 6.- THE HYDROSPHERE
WATER IS AN AMAZING SUBSTANCE.
• Water: is a very common substance on the Earth and in other places of the Universe. On Earth, it
is the only substance that can be found in the three states in a natural way.
It is a chemical compound formed by molecules. Each molecule is formed by two atoms of
hydrogen and one oxygen atom (H2O).
The form and the nature of its molecules give water some astonishing properties:
- When the temperature goes down from 4 ºC to 0 ºC, water expands (the opposite of the other
substances). Therefore, when it freezes (at 0 ºC), the density diminishes.
- Frozen water, having a lower density, floats on liquid water. Thanks to this, in rivers, lakes and
seas, fish can live in winter although the surface is frozen.
1.- Copy this information:
2.- Translate the following words:
Water: molecule:
Hydrogen oxygen:
Atom: chemical compound:
Expand: density:
Frozen water: frozen surface:
3.- Look at the picture on the right and draw a water molecule
4.- How is the water molecule formed?:
5.- Why does ice float?
Answer: Ice floats because frozen water, when having
__________ density, _________ on the liquid water.
6.- Why is it important that the ice floats?:

4. 7.- Which is the chemical formula of water:
8.- Complete:
The ________ and the ___________ of its molecules give ____________ some astonishing
properties:
- When the __________________ goes down from ________ to ________, water ____________
(the opposite of the other substances). Therefore, that when it ______________ (at 0 ºC), the
_____________ diminishes.
-___________ water, having a lower ____________, _________ on _______________________.
Thanks to this, in rivers, lakes and seas, _________ can live in winter although the surface is
_____________.
9.- Why is water an amazing substance?
10.- Look at the chart and complete the graphic. Use a red pen for water, a blue pen for iron and a
black pen for aluminium.
-5 ºC -4 ºC -3 ºC -2 ºC -1 ºC 0 ºC 1 ºC 2 ºC 3 ºC 4 ºC 5 ºC 6 ºC 7 ºC 8 ºC 9 ºC
Water 1cm3 1.1cm3 1.2cm3 1.3cm3 1.4cm 1.5cm 1.4cm 1.3cm 1.2cm 1.1cm 1.2cm 1.3cm 1.4cm 1.5cm3 1.6cm3
3 3 3 3 3 3 3 3 3
Iron 1cm3 1.05cm3 1.1cm3 1.15cm3 1.2cm3 1.25cm3 1.3cm3 1.35cm3 1.4cm3 1.45cm3 1.5cm3 1.55cm3 1.6cm3 1.65cm3 1.7cm3
Aluminium 1cm3 1.1cm3 1.2cm3 1.3cm3 1.4cm3 1.5cm3 1.6cm3 1.7cm3 1.8cm3 1.9cm3 2cm3 2.1cm3 2.2cm3 2.3cm3 2.4cm3
10º C
9º C
8º C
7º C
6º C
5º C
4º C
3º C
2º C
1º C
0º C
–1º C
–2º C
–3º C
–4º C
–5º C
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4
3
Volume (cm )

5. NAME: _________________________________________ DATE: ________ 1º ESO ___ (Bilingual)
PROPERTIES OF WATER.
• Water as a solvent: Water is the best known solvent. It dissolves almost everything, except fats.
• Salinity of water: Water can dissolve mineral salts, the quantity of mineral salts dissolved in water
is called salinity.
- Fresh water: It is called fresh water if it contains less than 1 % of dissolved salts.
- Salt water: It is called salt water if it contains more than 1 % of dissolved salts.
• Thermal properties of water: Water needs a lot of heat for its temperature to increase, but it also
loses heat very slowly (the other substances lose heat more quickly).
1.- Copy this information:
2.- Translate the following words:
Solvent: fats:
Salinity: fresh water:
Salt water: thermal properties:
3.- Complete:
____________ of water: Water can dissolve ___________________, the quantity of mineral
salts dissolved in water is called ______________.
- _________ water: It is called fresh water if it contains ______than ____ of dissolved salts.
- _________ water: It is called salted water if it contains ______ than ____ of dissolved salts.
4.- Write down whether the water in the pictures is fresh water or salt water.
5.- What is fresh water?
6.- What is salt water?

6. 7.- If water dissolves these substances write “Yes”. If water doesn’t dissolve these substances write
“No”
8.- What are the differences between the thermal properties of water and the thermal properties
of other substances?
9.-Why is water a good solvent?
10.- Look at these pictures. The percentage is the salinity of each glass of water. Write down ‘fresh
water’ or ‘salt water’
0.1 %
1.1 %
2.1 % 0.7 % 0.99 %
0.19 % 2.01 % 3.1 %
1.01 % 10.1 %

7. NAME: _________________________________________ DATE: ________ 1º ESO ___ (Bilingual)
THE STATES OF WATER.
• Water in liquid state: Most of the water on the Earth is in liquid state.
There is liquid water in:
- Oceans and seas: They are formed by salt water and cover three fourths of the Earth’s surface.
- Continental water: It is generally formed by fresh water. We find it in: rivers, lakes, streams,
torrents, lagoons, ponds, wells, underground waters, etc.
- The clouds: they are formed by accumulations of very small drops of fresh water.
• Water in gaseous state: It is a minimum part and it is part of the atmosphere.
• Water in solid state: Most of the water in its solid state is concentrated in the Polar Regions. The
rest is located in very cold areas for example on mountain tops.
It is spread this way:
- The polar icefields: they are the ice layers that cover the Artic and Antarctic oceans (in the
North and South Poles).
- The glaciers they are big masses of ice, accumulated on the Earth
1.- Copy this information:
2.- Translate:
Liquid state: solid state: North Pole:
Gaseous state: oceans: Glaciers:
Seas: continental water: underground waters:
Rivers: torrents: Icefields:
Lakes: lagoons: Cloud:
3.- Complete:
a) __________ in liquid state: Most of the water of the Earth is in _________________.
There is liquid water in:
b) ____________ and ___________: they are formed by _____________________ and cover
_______________________ of the Earth’s surface.
c) ______________________ water: It is generally formed by ______________________. We
find it in: __________, lakes, streams, ____________, ______________, ponds, wells,
_________________ waters, etc.

8. 4.- Match the three columns with arrows
Rivers
Lakes Solid state:
Fresh water Oceans
Torrents
Water vapor Gaseous state:
Lagoons
Salt water Glaciers
Seas Liquid state
Polar icefields
5.- How much salt water is there on the Earth?
6.- What are the glaciers?
7.- What are the polar icefields?
8.- Where are the icefields?
9.- Order the water on the Earth from the highest amount to the lowest amount: ‘liquid state’,
‘gaseous state’, ‘solid state’
1.- ________________________
2.- ________________________
3.- ________________________
10.- a) Where is the liquid water found?
b) Where is the gaseous water found?
c) Where is the solid water found?

9. NAME: _________________________________________ DATE: ________ 1º ESO ___ (Bilingual)
THE WATER CYCLE.
• The water cycle: Solar energy and gravity put the water of the Earth in continuous movement.
It has three big stages:
1.- The water goes up into the atmosphere: Solar energy heats the water of oceans, seas, rivers,
lakes, etc. The water evaporates and goes up into the atmosphere.
The living beings also transmit water to the atmosphere with their transpiration.
2.- The water returns to the terrestrial surface: When it arrives to the high and cold layers of the
troposphere, the water vapor
cools down and condenses.
Clouds are formed and the
wind makes them move.
Under certain conditions,
the water falls down in the
form of rain, snow or hail.
3.- The water circulates
through the terrestrial
crust: The terrestrial gravity
makes the water move down.
Torrents, streams, rivers, etc.
are formed, until they arrive
to lakes, seas or oceans.
A part of this water
infiltrates and forms the
underground waters.
1.- Copy this information (only the text):
2.- Translate the following words:
the water Cycle: water storage in oceans:
Gravity: Evaporation:
Precipitation: Infiltration:
Ground water storage: Surface runoff:

10. 3.- Complete:
The water cycle has three big stages:
1.- The water _____________________________________________________________
2.- The water _____________________________________________________________
3.- The water _____________________________________________________________
4.- Draw the water cycle and write down the words in English (with a red pen) and in Spanish
(with a blue pen):
5.- What does the water cycle put in continuous movement?
6.- How do the living beings transmit water to the atmosphere?
7.- How does the water return to the Earth’s surface?
8.- How does the water circulate through the terrestrial surface?
9.- What are the underground waters?
10.- The water falls down as: ________________, ___________________ or ___________.

11. NAME: _________________________________________ DATE: ________ 1º ESO ___ (Bilingual)
USES OF WATER.
• What do we use the water for?: The consumption of water has increased alarmingly.
We use it:
- To satisfy the basic needs: feeding, hygiene, etc. (about 5 daily liters per person).
- To improve our quality of life: to wash, to clean, etc. (about 80 daily liters per person).
- To generate wealth: agriculture, industry, transport, etc. (about 3,200 daily liters per person).
- For recreational activities: maintenance of facilities, etc.
For most of these activities drinkable water is needed. Drinkable water forms a very small part of
the terrestrial water (2.5 %).
1.- Copy this information:
2.- Translate:
Recreational activities: Consumption:
Maintenance of facilities: To wash:
Drinkable water: To clean:
basic necessities: Generate wealth:
3.- Write a “T” if the phrase is true and “F” if the phrase is false.
a) The consumption of water has increased alarmingly.
b) We use water to satisfy the basic arithmetic.
c) To generate wealth about 100 daily liters per person are used.
d) Drinkable water forms a very small part of the terrestrial water.
4.- How many liters of water do we need to satisfy the basic needs?:
5.- Is the terrestrial water drinkable?

12. WE ARE DESTROYING THE HYDROSPHERE.
Water pollution: It is any alteration of the properties of water that can harm our health and the health
of other living beings. This pollution can be produced by waste waters, chemical substances, metals,
plastics, batteries, etc. .
• Exhaustion of the reserves: If we consume water faster than it regenerates.
• Changes of the environment: Big constructions like dams, reservoirs or highways can gravely
modify the landscape.
6.- Translate the following words:
Water pollution: Chemical substances:
Exhaustion of the reserves: Changes of the environment:
Batteries: waste waters:
7.- Complete:
Water __________________: It is any alteration of the _______________ of _________ that can harm
our _____________ and the hearth of other ___________ __________. This pollution can be produced
by __________________, chemical substances, metals, ___________, ____________, etc.
8.- What can change the environment?
9.- When can there be an exhaustion of the reserves?
10.- Write below every picture “polluted landscape” or “non polluted landscape”.

13. NAME: _________________________________________ DATE: ________ 1º ESO ___ (Bilingual)
WATER MANAGEMENT.
• Quality water for all: We should watch over the quality of the water and commit to take care of it:
- In rivers, lakes, reservoirs, underground waters, etc. we should avoid putting in polluting
substances and we should not transform the natural riverbeds.
- Saving water mainly in agriculture, industries and in homes.
- To purify and to recycle water, we should purify the water of the cities before draining it into
rivers or seas, or use it for watering or cleaning the streets.
• Measures for sustainable water management:
1.- Rational extraction: That is to say to catch the water in times of abundance and to store it for
times of shortage.
2.- Treatment and distribution: So that it arrives to all the points with quantity and in the
appropriate condition.
3.- Reduce the consumption: By means of saving in agriculture, industry and in our homes.
4.- Purification of the waste waters: So that it can be reused or drained into nature without
endangering people’s health or the ecosystems.
1.- Copy the measures for sustainable water management:
2.- Translate the following words:
Quality water: Agriculture, industry and home:
Rational extraction: Purification of the waste water:
Riverbed: Reduce consumption:
Ecosystems: Sustainable water management:
3.- Complete:
Measures for sustainable management ______________:
a) _____________________: That is to say to catch the water in times of abundance and to store it for
times of shortage.
b) _______________________: So that it arrives to all the points with enough quantity and in the
appropriate condition.
c) ____________________________: By means of saving in agriculture, industry and in our homes.
d) ____________________________: So that it can be reused or drained into nature without
endangering people’s health or the ecosystems.
4.- How can we reduce consumption?:

14. 5.- Should we purify the waste waters?:
Answer: Yes, So that it can be reused __________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
6.- How can we have quality water for all?:
_____________________________________________, ___________________________________
and __________________________________________.
7.- What does ‘rational extraction’ mean?
8.- Where do we mainly save water?:
9.- When should we purify the water?
10.- Draw a clean landscape and then the same landscape contaminated