Download File - Mr. Haan`s Science

C. SEVERE STORMS
1.
a.
b.
c.
Thunderstorms
Storm which generates lightning and thunder
Can produce strong winds, heavy rain, and hail
Form from cumulonimbus clouds
d. Occurrence of Thunderstorms
1) At any given pt 2,000 thunderstorms in progress
2) Most common by tropics
3) About 45,000 every day
4) 16 million occur annually
5) Fl – most common – 100,000
e. Development
1) Warm, humid air rises and is unstable
2) 3 stages
a) Cumulus stage
i. Strong updrafts supply moist air
ii. Causes cloud to grow vertically
b) Mature stage
i. Size and amount of precip
can’t be supported by updraft
ii. Heavy precipitation &
sometimes hail produced
iii. Most active stage – strong
winds, lightning, precipitation
c) Dissipating stage
i. Downdrafts dominate
throughout cloud
ii. Rain cools ground off
iii. “Fuel” source is cut off
STAGES OF THUNDERSTORM
HTTPS://WWW.YOUTUBE.COM/WATCH?V=GTPJNFR6P3I
SINGLE CELL
Pulse Thunderstorms
-
Form at peek heating of day
-
Rain themselves out
-
30min – hour and done
MULTICELL STORM
-
Last longer
-
Usually have wind shear
-
Can produce severe weather
f. Lightning
1) Electrical discharge
2) B/w ground and cloud
or b/w clouds
3) Electrical storm
CLOUD TO GROUND
CLOUD TO CLOUD
4) Formation
a) Top of cloud becomes + and bottom becomes –
b) Stepped leader – neg. electricity towards ground
c) Pulls + streamer from ground towards leader
d) Leader connects with the streamer
e) Return stroke – current back to cloud
f) Forked lightning – stepped leader branches
STRAIGHT BOLT
FORKED BOLT
LIGHTNING STREAMERS
HOW LIGHTNING WORKS
https://www.youtube.com/watch?v=Q3Awp-3CxSU
HOW LIGHTNING RODS WORK
https://www.youtube.com/watch?v=zhu5pIrPw7U
5) Types
a) Heat lightning
i. Distant lightning
ii. Can’t hear thunder
i) Heavy snow fall
ii) Curvature of earth/atmospheric conditions
iii. Happens more on hot summer nights
b) Ball Lightning
i. Scientists rely on eye-witness accounts
ii. Many hypotheses for how it forms
iii. Characteristics
i) Appear simultaneously w/cloud to ground
lightning
ii) Typically spherical w/fuzzy edges
iii) 1-100cm (commonly 10-20cm)
iv) Red, orange, or yellow
v) 1 second – over a minute
vi) Usually move horizontally (can be
vertical, stationary, or completely random)
vii) Can disappear silently or explode
viii) Often smells like sulfur or ozone
ix) Often has brightness of a lamp
https://www.youtube.com/watch?v=4XRzD-2iuGU
c) Bolt “from-the-blue”
i. Very dangerous
ii. Can strike when it
is still sunny
iii. Typically stronger
and more vertical
storms
DIFFERENT KINDS
OF LIGHTNING
6) Safety
a) Crouch
b) Balls of feet
c) Don’t go outside
d) Don’t go by electronics
e) Hair stands on end
LIGHTNING FUN FACTS
1.
25,000 volts is required to jump 1 inch
2.
Lightning has hundreds of millions of volts
3.
50,000° F
4.
Time b/w lightning and thunder/3 seconds = distance in
kilometers
5.
2006 – 2012 what percent of people struck by lightning
were male?
82% of people struck by lightning were male
g. Thunder
1) Lightning makes air expand rapidly from heat
2) Air expands rapidly
3) Causes sound waves in all directions