2. 2. Evidence for Rotation
Coriolis Effect – the tendency of objects moving over the
earth (air, water, planes, projectiles) to be deflected (curve
away) from a straight line path. The French scientist, Gaspard
Coriolis, first explained the deflection of objects moving over
the surface due to Earth’s rotation
The deflection is to the right in the Northern Hemisphere
and to the left in the Southern Hemisphere.
This deflection occurs because Earth’s surface is rotating with
respect to the objects.
6. North Pole Projectile
A hockey puck is launched from
the north pole. As it heads
south, the earth turns to the
east, causing the puck to appear
to deflect to the west as viewed
by an earthbound observer.
Legend:
Red: Path on rotating earth
Gray: Path on stationary earth
7. Coriolis
Effect
The tendency for any moving body on or
above the earth's surface, e.g., an ocean
current, wind or an artillery round, to drift
sideways from its course because of the
earth's rotation.
8. The true shape of the Earth called an
Oblate Spheroid.
The diameter from the North Pole to the South Pole
(the shortest diameter) is approximately 12,714 km.
The equatorial diameter (the longest diameter) is
approximately 12,756 km. This is not a big
difference, but it does make the Earth not quite a
sphere.
9.
10.
11.
12. Something hanging from a fixed
point which, when pulled back
and released, is free to swing
down by force of gravity and
then out and up because of its
inertia.
Inertia: means that bodies in
motion, will stay in motion;
bodies at rest, will stay at rest,
unless acted on by an outside
force.
13. Evidence of Earth’s Revolution around
the Sun
Seasonal Constellations: Because of the Sun’s annual
motion, some constellations are visible at night only
during certain seasons.
Constellations are visible when the dark side of Earth
(away from sun) faces toward the constellation.
16. Ingredients for a storm…
Heat From the Sun
Differences in Air
Pressure
Water
17. What is a hurricane?
A hurricane is a large, swirling, low-pressure system that
forms over the warm Atlantic Ocean.
18.
19.
20. Hurricanes form over warm
ocean water.
Near the equator, warm ocean water
provides the energy that can turn a low
pressure center into a violent storm.
As water evaporates from the ocean,
energy moves from the ocean water to
the air. This energy makes warm air
rise faster.
Tall clouds and strong winds develop.
21. As winds blow across the water from
different directions into the low, the
Coriolis Effect bends their path into a
spiral.
The winds blow faster and faster,
around the low, which becomes the
center of a storm system.
24. Parts of a Hurricane
Eye - The calm, center of the hurricane.
Eyewall - The wall of dense thunderclouds surrounding the eye. The
strongest winds of the hurricane are in the eyewall.
Spiral Rainbands - A series of long, spiraling bands of rain clouds in a
hurricane.
25. Why do hurricanes seem to
die over land?
As long as a hurricane is
over water, the warm, moist
air rises and provides energy
for the storm.
When a hurricane reaches
land, however, its supply of
energy disappears and the
storm loses power.
26. Tornadoes
•Tornadoes form from severe
thunderstorms. They are very
destructive because they have
a high energy density. They
also don't last very long. This
makes it hard to learn about
them. Since scientists don't
know much about tornadoes,
it's also hard to forecast them
27. Tornadoes
The fastest recorded wind
speed is 230 miles per hour and
occurred in New Hampshire in
1934. Although, winds can get
faster in tornadoes. The
windiest place in the world is in
Antarctica.
28. In severe thunderstorms, wind at
different heights blows in
different directions and at
different speeds.
This difference in wind speed
and direction, called wind shear,
creates a rotating column parallel
to the ground.
29. A thunderstorm’s
updraft can tilt the
rotating column
upward into the
thunderstorm
creating a funnel
cloud.
• If the funnel comes
into contact with
Earth’s surface, it is
called a tornado.
30.
31. Tornado Alley
This map shows where most tornadoes form in the United States.
The red area is known as "Tornado Alley".
Warm moist air from the Gulf of Mexico collides with
Cold dry air.
32.
33. Thunderstorms
It is late afternoon. The white puffy clouds that have been growing
all day are replaced by a greenish sky. A distant rumble is
heard...then another. It starts to rain. A flash of light streaks the sky,
followed by a huge BOOM. Welcome to a thunderstorm.
37. How are thunderstorms created?
There are three ingredients for thunderstorms to form:
1. The air near the earth’s surface must be warm and moist. It rises or
moves upward, which is called an updraft.
2. The atmosphere must be unstable- the surrounding air is colder than
the rising air mass. As the warm air mass rises, it cools and turns into
water vapor, condenses and forms CUMULONIMBUS Clouds.
38. Vertical Air Movement
As the cloud continues to
build, ice particles form
near the top of the cloud.
As they get large-they
form H-A-I-L. As the ice
particles or H-A-I-L falls,
cold air moves down with
it, causing a downdraft.
39. Let’s Investigate!
How do updrafts form???
Draw and describe what happens.
In what ways is this demonstration
of water similar to warm air in a
thunderstorm?
Challenge: How could you create a
downdraft in this experiment?
40. Building Characteristics
Preventing Hurricane, Tornado
The foundation
Wind acting on the roof surfaces of a building can cause negative pressures
that create a lifting force sufficient to lift the roof off the building.
Once this occurs, the building is weakened considerably and the rest of the
building will likely fail as well. To minimize this vulnerability, the upper
structure ought to be anchored through the walls to the foundation.
Several methods can be used to anchor the roof. Typically, roof trusses are
"toenailed" into the top of the walls, which provide insufficient force to resist
high winds. Hurricane ties nail into the wall and wrap over the trusses to
provide higher force resistance.
41. Building Characteristics Preventing
Hurricane, Tornado
Earth-sheltering
Earth-sheltered construction is generally more resistant to strong
winds and tornadoes than standard construction. Cellars and
other earth sheltered components of other buildings, can provide
safe refuge during tornadoes.
42. Building Characteristics Preventing
Hurricane, Tornado
Dome homes
The physical geometry of a building affects its aerodynamic properties and
how well it can withstand a storm. Geodesic dome roofs or buildings have
low drag coefficients and can withstand higher wind forces than a square
building of the same area. Even stronger buildings result from monolithic
dome construction.
44. Building Characteristics Preventing
Hurricane, Tornado
Log house
A CAT 5 hurricane-proof log house is resistant to the winds up to
245 mph. Wall logs in such construction have to be made
of glued laminated timber and all other components of the
house have to be hurricane-resistant.
