2. • Water is a very common type of matter and it exist in all three states. Running
or flowing water is in a liquid state.
• Ice is water in a solid state.
• You cannot see water or smell water in its gaseous state because water gas is
invisible and odourless.
• However, there is water gas in the air around you all the time. We call water
gas in the air water vapour
3. WATER CYCLE
When matter changes from solid to liquid or from liquid to gas, we say it has
undergone a change of state. Water is one of the few types of matter
that we can observe changing from one state to another.
This diagram shows how water changes state in nature. This process is
called the water cycle.
4. • Remember that clouds are not
clouds of water vapour.
• They are actually made up of
tiny drops of liquid water.
• The drops join up and when
they get too heavy, they fall to
the ground in the form of rain.
• If it is really cold, then the
drops freeze and fall to the
ground as solid snow or
hailstones.
5. Water Cycle: From the Sky to the Land and Back Again
• All over the world precipitation falls from
the clouds as rain, snow or hail. In
mountainous areas with snow when the
weather warms up snowmelt runs down
toward sea level.
• As the runoff reaches lower elevations it
can end up in lakes, rivers eventually
leading to the ocean, or filter down to
groundwater.
• Subsurface, or ground, water can stay
below ground for a very long time in large
aquifers. Sunlight heats up the earth’s
surface and draws water out into the
atmosphere; this process is called
evaporation.
• It even draws water from plants! This is
called transpiration. In the sky, clouds are
created through condensation of water
vapor, continuing the water cycle
6. CONDENSATION
• Condensation is the process where water
vapor becomes liquid. It is the reverse of
evaporation, where liquid water becomes a
vapor. Condensation happens one of two
ways: Either the air is cooled to its dew point
or it becomes so saturated with water vapor
that it cannot hold any more water.
7. PRECIPITATION
• Precipitation is any liquid or frozen
water that forms in the atmosphere and
falls back to the Earth. It comes in many
forms, like rain, sleet, and snow. Along
with evaporation and condensation,
precipitation is one of the three major
parts of the global water cycle.
8. TRANSPIRATION
Transpiration is the loss of water from a
plant in the form of water vapor. Water is
absorbed by roots from the soil and
transported as a liquid to the leaves via
xylem. In the leaves, small pores allow
water to escape as a vapor.
9. PERCOLATION
• In physics, chemistry and materials
science, percolation (from Latin
percolare, "to filter" or "trickle through")
refers to the movement and filtering of
fluids through porous materials.
• Percolation is the process of a liquid
slowly passing through a filter.
10. EVAPORATION
• Evaporation is the process of a
substance in a liquid state changing to a
gaseous state due to an increase in
temperature and/or pressure.
• Evaporation is a fundamental part of the
water cycle and is constantly occurring
throughout nature.
