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Properties and importance of water

Hydrosphere

The hydrosphere is the total amount of water in the planet. It includes water on the surface of the planet, underground and in the air.

Water is a molecule which contains two hydrogen atoms and one hydrogen atom (H2O).

It is colourless (it is transparent), odourless (it has no smell) and tasteless (it has no taste). Water can exist in three states. arrow right

Gas

 GAS

Liquid

LIQUID

Ice

SOLID
Gas
Liquid
Solid
Deposition
Condensation
Freezing
Sublimation
Melting
Evaporation

When water heats or cools, it may change of state. Look at the possible changes.

Change of state of waterChanges of state of water. Yolanda Varela. (CC-BY-NC-SA)

Density

The density of a substance is its mass divided by its volume.

The density of a material changes when temperature and pressure vary.

Ice is less dense than water so when water  reaches its freezing point, 0º C, it floats on top of water.

Life in the water under frozen surfaces is possible.

Activity 1

1. Complete the words with the missing letters. Two letters in each gap.
H rosphere Tra parent Dens y S id Liq d
Odourl s Ox en Hy ogen Evap ation Su imation
Dep ition M s Me ing Fr zing Mol ule

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Activity 2

2. Listen and choose the words.
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Importance of water

Learn why water is essential for life.

Importance of water

Why is water important?. Yolanda Varela. (CC-BY-NC-SA)

4. Complete the statements with the corresponding words.

Water is important because...

1. It is the major of living

2. It serves to the

3. It contains that aquatic animals need to

4. It transports that plants and animals need to

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Ángeles Alvariño González

Ángeles Alvariño González was a research biologist and oceanographer.

She was born in 1916 in Ferrol, Galicia.

As a child she showed interest in science and reading. She attended the University of Santiago de Compostela and graduated in 1933. She studied English and French during the Spanish Civil War and when it finished, she resumed her studies at the University of Madrid, where she obtained a master's degree in Natural Science.

She taught biology, zoology, botany and geology in different colleges in Ferrol,  she worked as a fishery research biologist in Madrid and at the Spanish Oceanographic Institute in Vigo. In 1953 she researched in the Marine Biological Association laboratory in Plymouth, UK, in 1956 at the Woods Hole Oceanographic Institute on Cape Cod, Massachusets and in 1958-69 at the University of California.

Through her life she discovered 12 new Chaetognatha species, nine Sinophora and one medusa. She studied zooplankton in the Atlantic, the Pacific and Indian Oceans and its relation to pollution or ship movements.

In 1993 she received the Great Silver Medal of Galicia. In 2012 a research vessel of the Spanish Institute of Oceanography, named Ángeles Alvariño, was launched.

She died in San Diego, California, in 2005.

Angeles Alvariño

Ángeles Alvariño. Secretaría Xeral da emigración. (CC-BY-NC)
1. Read the text and write true(T) or false (F). Write in your notebooks the reasons why you think the statements are true or false.

Teamwork

2. In groups of three find answers for the following questions. Use the Internet, the school library or ask any member of your family.
1. Ángeles Alvariño didn't like studying.
2. She started studying at the University of Madrid after the Spanish Civil War.

a. Why couldn't Ángeles Alvariño reseach on board in the 50's in Spain? What other things couldn't women to in that period?

b. What is Aidanosagitta alvarinoae and Lizzia alvarinoae?

c. Can you place in a map all the places and oceans that are mentioned in the text?
3. In Spain she only worked in Vigo.
4. She worked on the west coast of the US for eleven years.
5. She discovered seventeen new marine species.
6. She based her studies on zooplankton in the Atlantic Ocean.

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