1. Water Dagmar Štelclová Petr Musil

2. Water atoms of water are connected by a covalent bond atoms of water are connected by a covalent bond the bond is polar, with one end slightly negative charged (δ – ) and the other slightly positive charged (δ + ) the bond is polar, with one end slightly negative charged (δ – ) and the other slightly positive charged (δ + )

3. Physical properties of water water is the only substance that exists in all three physical states under the climatic conditions of the Earth´s surface water is the only substance that exists in all three physical states under the climatic conditions of the Earth´s surface

4. Physical properties of water liquid water´s extremely high heat capacity–its ability to store large amounts of heat without a large temperature change liquid water´s extremely high heat capacity–its ability to store large amounts of heat without a large temperature change liquid water is a superior solvent, able to dissolve large amounts of variety of compounds liquid water is a superior solvent, able to dissolve large amounts of variety of compounds this ability of water to act this ability of water to act as a solvent also means as a solvent also means that it is easily polluted that it is easily polluted

5. pH–Why Is it Important? the pH of a sample of water is a measure of the concentration of hydrogen ions the pH of a sample of water is a measure of the concentration of hydrogen ionspHhydrogen ionspHhydrogen ions the term pH was derived from the manner in which the hydrogen ion concentration is calculated - it is the negative logarithm of the hydrogen ion (H + ) concentration the term pH was derived from the manner in which the hydrogen ion concentration is calculated - it is the negative logarithm of the hydrogen ion (H + ) concentrationion the pH scale ranges from 0 to 14 the pH scale ranges from 0 to 14pH scalepH scale pH of 7 is considered to be neutral, substances with pH of less that 7 are acidic; substances with pH greater than 7 are basic pH of 7 is considered to be neutral, substances with pH of less that 7 are acidic; substances with pH greater than 7 are basicacidic

6. pH of some more common substances

7. Standard values of water

8. Water –the medium of life essential to all life, water constitutes from 50% – 97% of the weight of all plants and animals and about 70% of your body essential to all life, water constitutes from 50% – 97% of the weight of all plants and animals and about 70% of your body is necessary for agriculture, manufacturing, transportation and countless other human activities is necessary for agriculture, manufacturing, transportation and countless other human activities

9. about 96,5% of the Earth´s total supply of water is found in the oceans and is too salty for drinking, growing crops and most industrial purposes except cooling about 96,5% of the Earth´s total supply of water is found in the oceans and is too salty for drinking, growing crops and most industrial purposes except cooling the remaining 3,5% is fresh water, but over ¾ of it is unavailable for use by plants, humans and other animals;because it lies too far under the Earth´s surface or is locked up in glaciers, the remaining 3,5% is fresh water, but over ¾ of it is unavailable for use by plants, humans and other animals;because it lies too far under the Earth´s surface or is locked up in glaciers, polar caps, polar caps, atmosphere and soil atmosphere and soil

10. What is the water cycle? i can easily answer,it describes the existence and movement of water on, in, and above the Earth i can easily answer,it describes the existence and movement of water on, in, and above the Earth Earth's water is always in movement and is always changing states, from liquid to vapor to ice and back again Earth's water is always in movement and is always changing states, from liquid to vapor to ice and back again the water cycle has been working for billions of years and all life on Earth depends on it continuing to work the water cycle has been working for billions of years and all life on Earth depends on it continuing to work

12. Vocabulary Earth´s surface slightlychargedderive manner in consideragriculturecountlesssupplycroppurposeglaciervapor,steam zemský povrch slaběnabitýodvodit tímto způsobem považovat, vzít v úvahu zemědělstvínesčetnězásobaúrodaúčelledovecpára

13. References Ecology, Ch. J. Krebs, Benjamin Cummings,2001 Ecology, Ch. J. Krebs, Benjamin Cummings,2001 Living in the environment, G. T. Miller jr. Wadsworth publishing company, Belmont, California, 1988 Living in the environment, G. T. Miller jr. Wadsworth publishing company, Belmont, California, 1988 http://ga.water.usgs.gov/edu/watercycles ummarytext.html http://ga.water.usgs.gov/edu/watercycles ummarytext.html http://waterontheweb.org/under/waterqua lity/pH.html http://waterontheweb.org/under/waterqua lity/pH.html