4. The Water Cycle
Water is constantly moving between sea, air and land
The sun shines and
the sea is heated
heat
5. The Water Cycle
Water is constantly moving between sea, air and land
Evaporation
The water
evaporates and
forms clouds
6. The Water Cycle
Water is constantly moving between sea, air and land
Condensation
As air rises it cools
and condenses. It
reaches the
ground as rain,
snow, sleet or hail.
7. The Water Cycle
Water is constantly moving between sea, air and land
The snow
melts and
flows
Lakes
form
Snow forms
10. Humidity
It is the amount of water vapor in the air .
The higher the temperature the more water
vapor it can hold
Warm air can absorb much more water vapor
than cold air
11. Relative Humidity
The amount of water vapor in the air compared to the
total amount that air can hold at that temperature .
When water can’t hold water vapor anymore the relative
humidity is 100%
12. • When the air is saturated or filled with water vapor
,any additional water vapor will condenses in to a
liquid ….This temperature is called “Dew point “
16. Naming clouds
• we can call the clouds according to their altitude by
adding prefix or suffix.
Example:
Prefix “Cirro “ Clouds formed at high altitude
“Alto “ Middle altitude
“Nimbo” They are clouds bringing thunder
storm
Suffix Nimbus They are clouds bringing
thunder storm
29. Stratus cloud
• Long lasting precipitation with smaller raindrops and snow
flakes
30. Measuring amount of rainfall
• People have measured rainfall for thousands of years.
• It is especially important for farmers to know how much
rain will fall this year.
• The instrument used to measure rain fall is called “Rain
Gauge”
31. Thunderstorm
• It begins to from when warm humid air moves upwards rapidly
• The sun heats a place on Earth’s surface ,which , in ,turn , warms the
air mass above it.
32. • Then a cold front may push under the warm air mass , or wind
may force it upward.
• The higher surrounding air is colder than the rising air mass.
• As the warm air cools, the water vapor in it condenses into air
droplets, which forms a cloud
33. • Soon the water droplets become heavy enough to fall as rain
.
• The falling rain pulls in cool air with it.
• Winds blow both upward and downward in the cloud .
• Negative electric charges build up in the bottom of the cloud.
34. • The charges travel through the air in a lightning discharge .
• The air along the path of a lightning bolt extremely hot
• The air along the path of a lightning bolt extremely hot
• The intense heat makes the air expand so fast that sound
waves are produced .
35. Tornado
• It is a violently rotating column of air that extends
downward from thunderclouds and touches the
ground.
36. • A tornado starts when winds spin a column of air that bulges
from the bottom of the cloud .
• Strong updrafts ,or rising air ,are already present inside this
bulge.
• Next warm, humid air is pulled into the often funnel-shaped
column.
• The air spins so fast that an area of very low pressure forms in
the center.
37.
38. • The swirling funnel starts to descend.
• Because of the low pressure air in the near by area
rushes into the funnel.
• The air in the funnel rotates upward around the
center, joining the storm above.
• The wind speed in the tornado can reach 400km/hr or
more.
39. • The force of the tornado ‘s winds destroy houses ,
cars and anything in its path.
40. Hurricane
It is a large ,rotating tropical storm
system with wind speeds of at least
119km/hr
41. What is a hurricane?
A hurricane is a very destructive and dangerous
storm. It forms in stages. The hurricanes are filled
with rain, strong winds, lightning, thunder, hail
and tornadoes.
Stages of the hurricane :
1)Tropical depression
2)Tropical storm
3)Hurricane (wind speed 120km/hr)
42.
43.
44. What is eye of a hurricane?
While some hurricanes, are
small, others can be quite
large. Hurricanes are mighty
storms.
In the center of a hurricane
is an eye. Ironically, the eye
is actually a calm area in a
hurricane.