secondary education 1º eso€¦ · web viewnatural sciences. unit 4. the hydrosphere....

SECONDARY EDUCATION 1 ESO

NATURAL SCIENCES

UNIT 4

THE HYDROSPHERE

a) Introductionb) Initial Assessmentc) Contentsd) Activitiese) Self-assessmentf) Other resources: bibliography and resources on the Internetg) Reinforcementh) Further Study / Research Project

Sistema Educativo SEK – Aula Inteligente Natural Sciences – 1ºESO – Unit 4 -1-

In order to complete this unit, you should know the meaning of these icons. They will help you know what kind of activity you are doing.

Oral activities Drawings

Use a separate piece of paper

Graphs

Reinforcement / Further study /Investigation project

@ Use Internet resources Self-assessment

Use daily press.

The activities of each one of the areas of interaction of the Middle Years Program (M.Y.P.) are indicated with the following symbols:

Approaches to learn Environment

Community and service

Health and social education

Homo faber


A/ INTRODUCTION

Reading

Henry Cavendish

Cavendish was an English chemist and physicist born in Nice (France) in 1731. From a noble family, he was educated in Peterhouse school in Cambridge and later moved to London where he lived for most of his life.

Very little is known about him, he never married and spent all of his time working on science experiments.

He conducted experiments in chemistry, heat measurement and electricity, but he never had any interest in publishing his work. After he died, twenty boxes of notes were found in his laboratory. When these were published it showed that Cavendish was one of the greatest scientists ever.

His first investigations were about arsenic and the temperatures at which gases became liquid. In 1776 he discovered hoydrogen (H2) as well as the composition of water (H2O).

He died in 1810 in London. He is known for his work in developing scientific experimentation. One of the laboratories in Cambridge University is named after him, where some of the most important experiments in modern physics have been done.


“The student will …”

1. To know the singularity the Earth as far as the water presence, its origin and distribution. 2. To know the characteristics oceanic and continental waters and the dynamics of the water in the nature. 3. To know the main properties of the water, their uses, the problems derived from these and the treatments that are realised envelope it.

Sciences Assessment Criteria

Criteria AssessmentA: One world 1-6B: Communication in science 1-6C: Knowledge & understanding of science 1-6D: Scientific inquiry 1-6E: Processing data 1-6


B/ INITIAL ASSESSMENT

REMEMBER

The water comes in three states on Earth: solid, liquid and gas. It is the only habitable planet.

Some of the techniques of separation of substances such as filtration, decanting and distillation are used to purify water and drinking water.

A dissolution is a homogeneous system formed by a solute and solvent, with which it is in greater proportion. Water is the best solvent.

LET’S BEGINWhat do you know about water?

The questionnaire will serve you propose to detect background that have on water and thus facilitate learning.1. Which would freeze at a lower temperature - a container with 1000 litres of water or another with 1 litre?

2. Name five solids and five liquids which contain water

Solids Liquids

3. Where would you float better, in oil or in water?

4. How many litres of water are there in a classroom 8m long, 5m wide and 3m high?

5. Write five domestic and five industrial uses of water.

Domestic Industrial

6. Where would water freeze first, on Everest or in your house?


7. Why does ice float on water?

8. Why is water used for washing clothes?

9. Can water clean itself?

10. Why is chlorine added to the water in swimming pools?


C/ CONCEPTS

The origin of water on Earth

Water on other planets

The water molecule – abundance, properties and importance

Sea water as a solution

Sodium, potassium and chlorine – abundance and properties

Continental water

Types of fresh water

Water vapour in the atmosphere

The water cycle

Water pollution

Water treatment and purification

Water and life

Water and health


CONCEPT MAP

WATER

Fresh Water Salt Water

Found in three states: (rivers, lakes, marshes)

TREATMENT

Treat TreatIce Liquid Vapour Drinking water Sewage Water

Sedimentation * Screening Physical Removal of oils, * Settling fats, solids etc * Filtration * Chlorination

* Fluoridation Oxidation -Organic

Biological decomposition

Sedimentation

Final stage Chlorination


D/ ACTIVITIES

THE ORIGIN OF WATER ON EARTH

There are several theories regarding the formation of the hydrosphere on Earth. The planet contains proportionately more surface water than comparable bodies in the inner solar system. Water in the form of gas coming from the interior of the Earth is not sufficient to explain the quantity of water, though some did come from the huge volcanic activity.

The early Earth was also hit by comets and water-rich asteroids. Much of the water on the surface today is thought to have originated from the outer parts of the solar system, such as from trans-Neptunian objects.

With the cooling of the Earth, the first lakes were formed in the craters left by meteors hitting the Earth’s surface.

1. Why does Earth have water in a liquid state?

2. In what form does water exist on Mars?

3. Explain the origin of water on Earth.

4. Make two graphs which represent:- The total distribution of water on Earth- The distribution of fresh water on Earth


http://en.wikipedia.org/wiki/Asteroid

http://en.wikipedia.org/wiki/Comet

http://en.wikipedia.org/wiki/Solar_system

5. Why were there no oceans on Earth during the first 500 million years?

6. What do the successive cycles of evaporation and condensation of water cause?

7. Make a table showing where water can be found on the various planets in the solar system.


REMEMBER THAT…

Ancient Greek explorers believed that the world was shaped like a flat disksurrounded by a large outer sea, Oceanus. The great philosopher, Tales (600 AD)thought that water was the origin of the Earth.

When chemists in the 18th century showed how water is a combination of hydrogenand oxygen, water lost its position as a primary element. However, the new scienceand philosophy discovered its importance in vital processes – dissolving carboncompounds which make up the basic substances of life forms.

Water has always influenced the development of human culture. Primitive manavoided dry deserts and impenetrable jungles. The great civilizations grew up wherelarge rivers (the Tiger, the Euphrates, the Indus, the Nile and the Yellow River)allowed man to water their land. Later, man added sails to their primitive boats andsailed the oceans.

Nowadays, water is fundamental to our lives. In some regions of the planet, the lackof water puts the future of those regions in danger, and the shortage of water is agrowing problem for the expansion of cities and industry.

Water is also a substance which evolves in nature in a cycle, in distinct stages,purifying itself continuously, which overcomes the effects of contamination.

As there is plenty of water on the Earth’s crust, in the atmosphere and in living beings,it must be managed well. Not only do we need drinking water, but also purifiedsewage for other uses.

8. Does water have shape? Why?

9. Who discovered the formula for water?

10. Compare water with vinegar and oil. Smell and taste these liquids. What conclusion do you reach?

11. What atoms does water have? What is its chemical formula?Sistema Educativo SEK – Aula Inteligente Natural Sciences – 1ºESO – Unit 4 -11-

12. Taking into account the previous questions, define water.

13. Explain the following types of water:

- drinking

- mineral

- thermal

- oxygenated

- distilled

- heavy

14. How do hydrogen and oxygen separate in water? Make a drawing to illustrate your answer and show the set up for this experiment.

15. What is sea water made of?

16. Where does the salinity of the seas and oceans come from?

17. The Dead Sea has around 225g of salt per kilo of water. What does this mean? Why is there such a high concentration of salt there?


DID YOU KNOW…

Sea water contains dissolved gasses, mainly oxygen, nitrogen and carbon dioxide. These dissolve in water with calcium and form calcium carbonate, needed for skeletons and shells of marine animals.

Elemental composition of Earth's ocean water (by mass)

Element Percent Element PercentOxygen 85.7 Sulphur 0.0885Hydrogen 10.8 Calcium 0.04Chlorine 1.9 Potassium 0.0380Sodium 1.05 Bromine 0.0065Magnesium 0.1350 Carbon 0.0026

18. Make a bar graph with the information in the table above.

19. Why is sea water salty? Does fresh water contain minerals?

20. Try washing a greasy plate with water. What happens? Try it again using soap or washing up liquid. What difference do you notice? What can you learn from these examples?

21. What are hard and soft water? Find out the properties of both.

22. What does an egg sink when you put it in pure water, but it floats when you put it in salt water?

23. What property of water means that it is usually not found in its pure state?


http://en.wikipedia.org/wiki/Carbon

http://en.wikipedia.org/wiki/Magnesium

http://en.wikipedia.org/wiki/Bromine

http://en.wikipedia.org/wiki/Sodium

http://en.wikipedia.org/wiki/Potassium

http://en.wikipedia.org/wiki/Chlorine

http://en.wikipedia.org/wiki/Calcium

http://en.wikipedia.org/wiki/Hydrogen

http://en.wikipedia.org/wiki/Sulfur

http://en.wikipedia.org/wiki/Oxygen

PROPERTIES OF WATER

1. Water is a bad conductor of heat.2. Pure water does not conduct electricity.3. Water is most dense at 3.8 degrees C. For this reason, ice (the solid state of water) floats on water.4. Water is a good solvent. Many substances can dissolve easily in it. This allows our blood (mainly water) to carry substances such as glucose which are dissolved in it.5. Water has a high heat capacity, which means that is requires a lot of heat to raise the temperature of water. However, once it is warm, it retains heat for a long time.

YOU SHOULD ALSO KNOW…

An unusual feature of water frozen at a pressure of one atmosphere (i.e. sea-level) is that the solid is 8% less dense than liquid water. Ice has a density of about 0.9 g/cm³ at 0°C, whereas water has a density of almost 1 g/cm³ at the same temperature. Liquid water is most dense, essentially 1 g/cm³, at 4°C and becomes less dense as the water molecules begin to form the hexagonal crystals of ice as the temperature drops to 0°C. (In fact, the word "crystal" derives from Greek word for frost.) This is due to hydrogen bonds forming between the water molecules, which line up molecules less efficiently (in terms of volume) when water is frozen. The result of this is that ice floats on liquid water, an important factor in Earth's climate.

If ice observed the usual pattern of expansion, rivers and lakes would freeze from the bottom to the top and those which froze in winter would not defrost in summer. The aquatic life in rivers and lakes would not be able to survive.

24.Why are the temperatures in Valencia milder than in Madrid?

25.What is a glacier and how is it formed?

26.What is an aquifer? Explain how it is formed.


http://en.wikipedia.org/wiki/Climate

http://en.wikipedia.org/wiki/Molecules

http://en.wikipedia.org/wiki/Hydrogen_bond

http://en.wikipedia.org/wiki/Ice_crystals

http://en.wikipedia.org/wiki/Crystal

http://en.wikipedia.org/wiki/Hexagonal_(crystal_system)

http://en.wikipedia.org/wiki/Density

http://en.wikipedia.org/wiki/Atmosphere_(unit)

COULD WE LIVE WITHOUT WATER?

Water is the source of life.

For humans, water is more important than food. We can survive many days without eating but we can’t survive more than four or five days without water.

More than 60% of our body is made of water. Our brains are 86% water, blood 79%, muscles 76% and bones 25%. Jellyfish are up to 95% water, spinach 92% and grapes 80%.

We need a lot of water because we also lose a lot of water. We consume about 2.5 litres a day. Water is needed to transport food, regulate body temperature and is used in chemical reactions which living beings carry out.

27. Make a bar graph using the information above to represent the different percentages of water there is in living beings.

28. Put the following information into diagrams:

a/ water use;agriculture 56%industry 36%domestic 8%

b/ domestic water use;toilet 32%bath/shower 30%waste 13%dish washing 10%gardens 3%drinking 3%

29. The standard of living in a country has a direct influence on the amount of water used in that country. Make a study of water use in different countries, comparing developed and developing countries.


THE WATER CYCLE

30. Draw a diagram of the water cycle in nature.

31. How does subterranean water contribute to the water cycle?

32. What would happen to life if there was no water cycle?

33. Why can we say that the Earth is like a great water cleaner powered by solar energy?

34. Does water appear in its three states in the water cycle? How so?


LEARN MORE…

All living beings have water inside them. Water is found inside their cells, in the spaces between the cells, in their blood and so on. Water has a very important function in the chemical changes that happen inside the body. Water dissolves all the substances that take part in these chemical changes. This is the reason why all living beings need water which they can get from their surroundings.

Humans also use water to improve their quality of life and for entertainment. Water is used in various industries (food, textiles, power plants... ).

In addition, because water takes such a long time to heat up and to cool down, it causes sea breezes. Cool breezes towards the land when it is hot and warm breezes when it is cold. This means that water is a major regulator of climate. Water has physical and chemical effects on nature. Physical effects include breaking materials, erosion, transport and sedimentation.

Limestone allows water to pass through the cracks, forming caves and underground water. Landscapes that develop in this way are known as karst landscapes.

35. Why is water so important for plants and animals?

36. Explain the effect of water and ice on the landscape.

37. Where do you think rain would cause more erosion, in desert areas or in areas with vegetation? Why?

38. What are icebergs and how are they formed?

39. Give some examples of how man uses water to improve his quality of life.

40. How is electricity generated from water?


CONTAMINATION AND PURIFICATION OF WATER

Our drinking water comes from rivers, lakes and subterranean water which flows in the aquifer mantle, but this water is not suitable for drinking. It may contain particles of dirt or disease-causing bacteria. It may also contain radioactive elements or toxic products. Water to our homes therefore has to be treated.

There are five steps in the treatment of drinking water. 1. Screening: The water is first passed through a wire mesh to remove larger

pieces of dirt and rubbish2. Settling: The water is then stored in large settling tanks or reservoirs, which

allows time for the large and medium sized dirt particles to settle out to the bottom.

3. Filtration: The water is then passed through filtration beds. These contain sand on top of gravel, through which the water filters. Even very small particles are removed in this way. The dirt stick to the sand and gravel as it passes through.

4. Chlorination: Small quantities of chlorine are added to kill any bacteria present.

5. Fluoridation: Small amounts of chlorine compounds are added to help prevent tooth decay.

Water deteriorates with use; once it has been used it becomes sewage. This sewage must be treated in order to remove toxic or dangerous substances which could harm the environment or people. The site where the process is conducted is called a sewage treatment plant. The flow scheme of a sewage treatment plant is generally the same for all countries:

1. Primary treatment is to reduce oils, grease, fats, sand, grit, and coarse solids. This step is done entirely with machinery, hence the name mechanical treatment.

2. Secondary treatment is designed to substantially degrade the biological content of the sewage such as are derived from human waste, food waste, soaps and detergents. Bacteria and protozoa consume biodegradable soluble organic contaminants (e.g. sugars, fats etc.), so we call this the biological treatment stage. The final step in the secondary treatment stage is sedimentation to separate the sewage water and filtered material.

3. Tertiary treatment provides a final stage to improve the quality to the standard required before it is discharged to the environment (sea, river, lake, ground, etc.). Sand filtration removes much of the remaining suspended matter.

41. What toxic substances or microorganisms does polluted water have?


42. What are the different types of pollution?

43. Find the meaning of the following terms in a scientific dictionary:

- pesticide- pathogen

44. Explain some of the reasons why we should avoid pollution in our rivers, seas and oceans.

45. Why is it important to find out whether there is subterranean water somewhere before choosing to put a rubbish dump there?

46. Is all fresh water drinkable? Explain your answer.

47. What useful products can we get from process of sewage treatment?

48. What is the relationship between water and health?


49. Why are ozone and chlorine added during the process of making drinking water?

50. How can you get salt from sea water? List some uses for salt.

51. What are the differences between making drinking water and purification of sewage?


GLOSSARY OF KEY WORDS

Desalination

Aquifer

Pure water

Transpiration

Self-purification

Oxygenated water

Pollution

Solvent

Hard water


E/ SELF-ASSESSMENT- UNIT 8 - NATURAL SCIENCES

Name .......................................................................... Group .................

1. Explain the origin of water on Earth.

2. On Mars and on Venus, in what state is water found?

3. How is water distributed on Earth?

4. Explain the water cycle.

5. What are the properties of water?

6. Define the following concepts:

Organic residue

Transpiration

Pesticides

Hail

Pollution

Self-purification

Aquifer

7. Explain the steps involved in water treatment.

8. What useful products can we get from the process of sewage treatment?


F/ OTHER RESOURCES: BIBLIOGRAPHY AND INTERNET RESOURCES

Sources of information:

Student’s Book: Ecosfera, tema 12. Editorial SM Cambridge Encyclopaedia Hutchinson Encyclopaedia Classroom Library

Software: Encarta Encyclopaedia 2000

Internet Resources:

Websites:

http://www.exploratorium.edu/climate/hydrosphere/index.html

www.altavista.es

www.enciclonet.com

www.arrakis.es/

www.pntic.mec.es

www.maseducativa.com

www.conicyt.cl/explora/agua/inicio.html

http://www.aillweecave.ie/

www.foe.co.uk


http://www.foe.co.uk/

http://www.aillweecave.ie/

http://www.conicyt.cl/explora/agua/inicio.html

http://www.maseducativa.com/

http://www.pntic.mec.es/

http://www.arrakis.es/

http://www.enciclonet.com/

http://www.altavista.es/

http://www.exploratorium.edu/climate/hydrosphere/index.html

G/ REINFORCEMENT

Name .............................................................. Group ................

R.1. In contrast with other liquids, water increases in volume when it becomes a solid. What happens as a result? At what temperature is water most dense?

R.2. Explain the origin of water on Earth.

R.3. Why are the oceans and seas important for life on planet Earth?

R.4. What are the most significant properties of water?

R.5. Describe how the water cycle works.

R.6. How is water found in its three states?

R.7. How does water influence the climate in coastal areas? Why does this happen?

R.8. Explain the types of water pollution.

R.9. List the main ways in which man uses water to improve his quality of life.

R.10. What residual substances, in suspension or dissolved, from industry or agriculture, does polluted water contain?


H/ FURTHER STUDY / RESEARCH PROJECT

1. Find out about alternative energy sources in Ireland. How is water used to generate electricity on the River Shannon? How about wind or wave energy?

2. Where in Ireland are there protected wetlands? What benefits do these areas have?

3. As it flows across the Earth, water changes, erodes, dissolves, transports and deposits materials. For this reason, water is considered a principal geological agent on Earth.

3.1 What phenomena result?3.2 Analyse the terms erosion, transportation and sedimentation in the light of the

previous question.3.3 How do the seas and oceans act as agents of erosion and deposition? What

are the most common coastal features that they produce?3.4 Investigate further to find out about the action of continental waters (rivers,

lakes, glaciers) and subterranean waters.3.5 Where in Ireland is there a good example of a karst landscape? What special

features are in the caves?

4. Water covers 71% of the surface of the Earth, but 97% of it is salt water. Therefore, only 3% is fresh water. Furthermore, 79% of the fresh water is locked up in polar icecaps and glaciers, meaning that only 1% is available to humans.

4.1 Find a map of water availability. Name three countries where there are problems finding water all year, and name three where there is always plenty of water. 4.2 Investigate the sources of water pollution and the consequences for the environment.


secondary education 1º eso€¦ · web viewnatural sciences. unit 4. the hydrosphere....

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