Water exists on Earth in three main forms: solid (ice), liquid (bodies of water), and gas (water vapor). About 71% of the Earth's surface is covered by water, mostly in oceans. Water cycles between these forms through natural processes. A key property of water is that solid ice floats on liquid water, due to hydrogen bonding causing ice to have a less dense crystalline structure than liquid water. This allows ice to survive on water surfaces like lakes and oceans, an important factor for life.

2. Presented By:
Name : Deep S. Mistry
Roll No. : 06
Water Forms

3. What is Water?
 Definition:
 A colourless, transparent, odourless, liquid which forms the seas, lakes,
rivers, and rain and is the basis of the fluids of living organisms.
 If earth’s map is observed keenly, it is found that most of the area is
blue in color, indicating the presence of water.
 About 71% of earth’s surface is covered with water. Water is present in
oceans, seas, lakes, rivers, ice caps, as ground water and in the
atmosphere.

4. Portion of Water on Earth

5. Forms of Water
 Forms of Water:
 Water is being continuously used and water conservation is the major
concern in the present scenario.
 Water cycle has helped in maintaining water on the surface of earth for
millions of years.
 The water circulated in water cycle takes three different forms –
• Solid
• Liquid
• Gas

6. Forms of Water (Conti…)
 The solid form of water – ice, is found
at the poles of the earth, the snow covered
mountains and the glaciers.
 Liquid form is present in the rivers,
lakes, seas and oceans.
 The gaseous form of water, water
vapour is present all around us.

7. Solid Water Form
 Solid Water:
 When water freezes, its molecules move further apart, making ice less
dense than water.
 Water freezes at 0° Celsius, 32° Fahrenheit. Celsius is scale that
measures temperature.
 This means that ice will be lighter than the same volume of water, and
so ice will float in water.
 Ice, snow, icicles, ice on a skating rink and frost are examples of water
in the solid state.

8. Solid Water Form (Conti…)

9. Liquid Water Form
 Liquid Water:
 Liquid water is wet and fluid.
 We use liquid water in many ways, including washing and drinking.
 Pure liquid water is free of salt, rocks, soil, and garbage.
 The formation of hydrogen bonds is an important quality of liquid
water that is crucial to life.
 In liquid water, hydrogen bonds are constantly formed and broken as
the water molecules slide past each other.
 The breaking of these bonds is caused by the motion (kinetic energy)
of the water molecules due to the heat contained in the system.

10. Liquid Water Form (Conti…)

11. Gas Water Form
 Gas Water:
 Vapor is always present in the air around us. You cannot see it.
 When you boil water, the water changes from a liquid to a gas or water
vapor.
 As some of the water vapor cools, we see it as a small cloud called
steam. This cloud of steam is a miniversion of the clouds we see in the
sky.
 At sea level, steam is formed at 100° Celsius, 212° Fahrenheit.

12. Gas Water Form (Conti…)

13. Biological Significance
 Biological Significance of Ice's Ability to float on water:
 As water is boiled, kinetic energy causes the hydrogen bonds to break
completely and allows water molecules to escape into the air as gas
(steam or water vapor).
 When water freezes, water molecules form a crystalline structure
maintained by hydrogen bonding.
 Solid water, or ice, is less dense than liquid water.
 Ice is less dense than water because the orientation of hydrogen bonds
causes molecules to push farther apart, which lowers the density.

14. Biological Significance (Conti…)
 For other liquids, solidification when the temperature drops includes
the lowering of kinetic energy, which allows molecules to pack more
tightly and makes the solid denser than its liquid form.
 Because ice is less dense than water, it is able to float at the surface of
water.