Artificial Intelligence In Microbiology by Dr. Prince C P
Water Cycle.ppt
1.
2. Could you be drinking
the same water a saber
tooth tiger lapped up?
What do you think? Is
the water we have on
earth today the same
water that was here
millions of years ago?
Are you drinking the
same water a dinosaur
drank?
Water on earth moves in a
continuous cycle. This is called
THE WATER CYCLE. There
is about the same amount of
water on earth now that there
was when the dinosaurs
roamed our planet.
3.
4. The cycle starts when the sun's heat provides
energy to evaporate water from the surface.
Then, winds lift the water vapor from the ocean
over the lands into the atmosphere. The water
vapor cools and condenses into droplets to form
clouds, and when the conditions are just right, the
clouds release water as rain or snow. About 80%
of the rain falls in the oceans, but the rest falls
onto land. Rivers and streams collect water from
the ground and return it to the ocean so the whole
cycle can start all over again. The water cycle
never ends because the salty ocean water
constantly supplies fresh water to the continents.
5.
6. One process which transfers water from the ground back
to the atmosphere is evaporation. Evaporation is when
water passes from a liquid phase to a gas phase. The gas
phase of water is water vapor. Water vapor is invisible.
Rates of evaporation of water depend on factors such as
solar radiation, the temperature, humidity, and wind.
Water that is held in lakes and rivers evaporates directly
into the atmosphere, but some of the water in the ground
may also be returned to the atmosphere by way of
evaporation through the
soil surface. Of course,
the ocean is the greatest
source for water
evaporated into the
atmosphere.
Evaporation
7. Condensation is the change of water from its gaseous form
(water vapor) into liquid water. Condensation generally
occurs in the atmosphere when warm air rises, cools and
looses its capacity to hold water vapor. As a result, excess
water vapor condenses to form cloud droplets.
8. Precipitation is the main way for transporting water from
the atmosphere to the surface of the earth. There are
several forms of precipitation, including rain, hail, snow,
sleet, and freezing rain.
9. Groundwater is all the water that has gone through the
earth's surface and is found in one of two soil layers. The
one nearest the surface is the "zone of aeration", where
gaps between soil are filled with both air and water. Below
this layer is the "zone of saturation", where the gaps are
filled with water.
10. Transpiration is the process by which plants return
water to the atmosphere. After absorbing water from
the ground, plants release water through their leaves.
Transpiration helps plants stay cool, in the same way
perspiration keeps humans and animals cool.
11. Runoff is the movement of land water to the oceans, mostly
in the form of rivers, lakes, and streams. Runoff consists of
precipitation that hasn’t evaporated, transpired or
penetrated the surface to become groundwater. Even the
smallest streams are connected to larger rivers that carry
billions of gallons of water into oceans worldwide.
12.
13. The Sun's heat
provides energy to
evaporate water from
the Earth's surface
(oceans, lakes, etc.).
14. Evaporation occurs when
heat acts on water until
the temperature becomes
warm enough to change
water into a gas.
15.
16. Condensation is
the cooling of
water vapor until
it becomes a
liquid. As the dew
point is reached,
water vapor
forms tiny visible
water droplets.
When these
droplets form in
the sky and other
atmospheric
conditions are
present, clouds
will form.
17.
18. When the clouds meet cool air over land, precipitation
(rain, sleet, or snow) is triggered, and water returns to the
land (or sea).
19.
20.
21. A long, long, long time later, two very bored drops of
water emerge from the bottom of the glacier.
Most of the water flows downhill as runoff (above ground
or underground), eventually returning to the seas as
slightly salty water.
Editor's Notes
Define cycle: Any complete round or recurring series. Have kids brainstorm cycles they know about, and why the term water cycle makes sense.
Yes, the water we have on earth has been here since the beginning. There always remains the same amount. It may become polluted, but it always recycles and is used over and over again.
The description below is taken from the next slide. You might want to talk through this information with the picture to guide students through it.
The cycle starts when the sun's heat provides energy to evaporate water from the surface. Then, winds lift the water vapor from the ocean over the lands into the atmosphere. The water vapor cools and condenses into droplets to form clouds, and when the conditions are just right, the clouds release water as rain or snow. About 80% of the rain falls in the oceans, but the rest falls onto land. Rivers and streams collect water from the ground and return it to the ocean so the whole cycle can start all over again. The water cycle never ends because the salty ocean water constantly supplies fresh water to the continents.
In view slideshow mode, you can click on each of the underlined words and it will take you to a website about that word. I wouldn’t suggest doing it, as kids will get tired of it, but you might want to select one that you think needs explanation. I sort of think these words don’t need much explanation for fifth graders.
Note how the arrows lead you through the cycle. Heating-evaporation; cooling-condensation; precipitation; ground water to oceans and other bodies of water.
Stress that water vapor is invisible. You cannot see it.
Students have difficulty getting the idea that clouds are not vapor. Vapor is invisible. Vapor must be cooled in order to condense into the water droplets that mass together to form clouds.
Note the streams that carry runoff to the ocean.
Ask the students what is going on now. (The sun is heating the water and the droplets are being evaporated.
Use this graphic to review the water cycle, including all of the vocabulary.
Now see if kids can identify what’s happening at each number.
The Sun heats the ocean.
Ocean water evaporates and rises into the air.
The water vapor cools and condenses to become water droplets which form clouds.
When enough droplets gather, they become heavy enough to fall to Earth as precipitation.
Some water collects into the ground. The rest goes flows by rivers back to the ocean.