Water - source of Life!!!

Transcription

1 Water - source of Life!!!

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3 What is Water? H 2 O It is a tasteless and odourless, transparently clear and colourless liquid. It is made up of two of the most common elements of nature: hydrogen ( 2 parts) and oxygen ( 1 part) Water is irreplaceable as a natural substance and primary source of all life on earth.

4 Water as a solvent water is referred to as the universal solvent substances that dissolve in water are e.g. salts, sugar, acids, alkalis, and some gases (oxygen, carbon dioxide) fats and oils do not mix well with water

5 is a continuous exchange of water within the hydrosphere, between atmosphere, soil water, surface water, groundwater and plants consisting of the following transfer processes: Evaporation from oceans and other water bodies into the air. The water cycle Transpiration from land plants and animals into the air. Precipitation from water vapour condensing from the air and falling to earth or ocean. Runoff from the land usually reaching the sea.

6 2/3 of the globe is covered with water 2/3 of all cells contain water Water is the only substance in the world to be found naturally in all 3 states: solid ice liquid water gas water vapour Water freezes at 0 o C and boils at 100 o C

7 Water on Earth oceans hold 97% of surface water glaciers and polar ice caps 2,4% rivers, lakes, ponds 0,6% below ground in aquifers 1,6% clouds/vapour in the air 0,001% But only 2.4% of all the water resources are freshwater (glaciers/ice polar caps)

8 Water on Earth Ocean Glaciers and Polar ice Rivers, Lakes, Ponds Below ground in aquifers Clouds/vapour in the air freshw ater From these 2.4% only 10% can be used as drinking water. The global water resources are estimated at billion cubic kilometres The complete amount of fresh water is estimated at million cubic kilometres

9 Water over land has several forms: rain snow hail with contribution from fog and dew Condensed water in the air may also refract sunlight to produce rainbows

10 Marine Life During Winter The solid form of water (ice) is actually less dense than the liquid form. This is very unusual!!!!! Water has its highest density at 4 o C. That means that at the bottom of a body of water the water will usually be at least 4 o C. This is why aquatic organisms are able to live, even in the winter.

11 Water in organisms Organisms usually contain 60% to 90% water. human beings 55% -78% (depending on body size) lowest : plant seed 20% highest: jellyfish 99% green leaves: 80% 90% Water helps all organisms with metabolism, and specifically helps plants with photosynthesis and support.

12 Did you know? How much water food contains? spinach 98% carrots 89% eggs 86% flour 8% apples 84% potatoes 75% pork 58% butter 20%

13 Water in our human body People can live 14 days or longer without food, but only some days without water. Water cannot be replaced by anything else. A grown up person contains about 42 l of water. Water cannot be stored. That is why we have to take in 2,5 to 3 l of water a day. You die if your body loses 12% to 20% of water. Water is indispensable for the existence of all living beings, animal or vegetable.

14 Water is excreted from the body in multiple forms: through urine and faeces through sweating by exhalation of water vapour in the breath Humans require water that does not contain too many impurities. The single largest freshwater resource suitable for drinking is Lake Baikal in Siberia which has a very low salt and calcium content and is therefore very clean.

15 Water in Sexual Reproduction During fertilization the male sex cell, the sperm, must get to the female sex cell, the ovum, in order to make the zygote which makes a new individual In organisms adapted for internal fertilization, the sperm is transported in semen which contains mostly water In organisms using external fertilization the sperm can be transmitted through in the water habitat.

16 Water-Topic of the new millenium In all religions and cultures water was considered holy and the source of life. Paracelsus praised the precious liquid as a remedy. But unfortunately we no longer take good care of our water. Its waste and pollution has reached an alarming extent.

17 What can we do not to waste water and to keep it clean? Don t let it run without being used Use water savers on taps and sanitary installations Repair all leaks Comply with restrictions on watering gardens or washing cars Keep debris out of gutters and drains Use only small amounts of lawn and garden chemicals Have septic tank checked every 3 to 5 years Keep soil erosion on your property low by planting grass Respect it, preserve it, it s a question of survival!!!

18 Who does water belong to? Water is a common asset of all the inhabitants of the earth. But there s an unequal distribution. Hundreds of millions of people have to walk for hours to get water. More than 2 billion people do not have direct access to clean water. To survive we do not have the right to pollute or waste water. Water sources have to be used in a reasonable manner to be shared between billions of human beings, not forgetting future generations.

19 Climate Change Water Crisis glaciers in the Rocky Mountains and Sierra Nevada could disappear California will face a shortfall by 2020 nearly as great as the amount of water consumed today Temperatures rise and the Himalayan glaciers the sources of Asia`s biggest rivers ( Ganges, Indus, Brahmaputra Yangtze, Mekong ) could disappear by

20 Climate Change Water Crisis Experts warn for a long term ecological damage for the area of the Murray and Darling River. (Australia) Water deficits will not harm only smaller countries (Egypt, Algeria, Iran, Mexico, Pakistan) but also larger ones( China, India). India, China, Bangladesh, Nepal and Myanmar could experience floods followed by droughts in coming decades.

21 Average water consumption per person/ year in some countries USA 2200 m³ Australia 1300 m³ Germany 650 m³ India 600 m³ Algeria 150 m³ Ghana 50 m³ Uganda 30 m³

22 Principle manifestations of the water crisis inadequate access to safe drinking water for about 884 million people groundwater overuse leading to diminished agricultural yields overuse and pollution of water resources harming biodiversity regional conflicts over scarce water resources sometimes resulting in warfare The WHO ( World Health Organisation) estimates that 1.5 billion people in developing countries have no access to safe water and sanitation.

23 Contaminated water causes high mortality rates from cholera, typhoid, diarrhea, stomach worms and giardiasis. More than 4 million children die every year from preventable diseases like diarrhea. Unsafe drinking water is the world s no 1 killer. It s responsible for 80% of all sickness in the world. Access to clean water and efficient sanitation is a basic human right!!!!!

24 A 2006 United Nations report says: Water insufficiency is often due to mismanagement, corruption, lack of appropriate institutions, bureaucracy inertia and a shortage of investment in both human capacity and physical infrastructure. But it also says, There is enough water for everyone!!!

25 Did you know?

26 Did you know, that every 8 seconds a child dies by drinking contaminated water?

27 Did you know, if the entire ice on land melts, sea level will rise by 70m.

28 Did you know, ostriches stick their heads in the sand to search for water.

29 Did you know, the brain consists of about 75% water.

30 Did you know, in our life there are about litres of H 2 O, which we absorb.

31 Quiz

32 How much of the earth is covered with water? A 2/3 B 1/2 C 1/4 D 1/5

33 What is the boiling point of water? A 200 B 150 C 85 D 100

34 What is the freezing point of water? A -10 B -100 C 5 D 0

35 How much water is there on earth? A km³ B km³ C km³ D km³

36 What do we use most of the water for worldwide? A agriculture B household C industry D other

37 What is the chemical formula of water? A CO 2 B H O 2 C CH 2 D HCl

38 How long can people survive without water? A 3 or 4 days B 10 days C 7 days D 14 days

39 How much salt water covers the earth? A 71% B 4% C 50% D 32%

40 How else do we call the earth because of its high water content? A Water Earth B Blue Planet C Water Planet D Blue Earth

41 Designed by the Information Technology class 10