ATMS 120 Exam 3 With
Complete Solution
Lightning: 50 year average (in US) - ANSWER ~600 struck per year
~60 die per year
Lightning: 10 year average (in US) - ANSWER 30 die per year
Cost of Lightning in US per year - ANSWER $4-5 billion
Lightning basics - ANSWER - Lightning=electrical discharge
- Contains 1+ billion volts, 30,000+ amps
- Length = typically about 5 km long
- Width = 1 inch (2-3 cm)
- 100 strikes per second on earth
- 9 million per day
- Temp = 30,000 degrees C (5 times hotter than the surface of the sun)
How does a cloud become electrified? - ANSWER the negative charges move
up to the positive charges building up at the top of the cloud
in order for a cloud to produce lightning, it must contain... - ANSWER ice
4 types of lightning stokes - ANSWER 1) intra-cloud
2) cloud to cloud
,3) cloud to air
4) cloud to ground
Types 1-3 makes up 80% of lightning strokes
Type 4 makes up 20% of lightning strokes
The negative Polarity Lightning strike - ANSWER ~95% of all
cloud-to-ground strikes
Steps of the negative polarity lightning strike - ANSWER 1) stepped leader
2) when they meet = return stroke
3) return strike opens an "ionized path"
4) when it meets the positive charge = second return stroke
stepped leader - ANSWER - electrons come down from cloud base searching
for a path of least resistance to a positive charge
- fork-like patter
- traveling spark of positive charge moves up to meet it
- can barely see any of this
when they meet = return stroke - ANSWER - electrons from cloud base
suddenly rush down the open path
- current travels back up producing the bright flash
- heats air to 30,000 degrees C
return stroke opens an "ionized path" - ANSWER - any left over electrons
from cloud base can then rush back down the same path
, - called the "dart leader"
when the "ionized path" meets the positive charge = second return stroke -
ANSWER - second bright flash
- can occur multiple times
Thunder - ANSWER the lightning heats the air around the bolt to 30,000
degrees C
-> the air rapidly expands, creating a huge pressure surge
math equation of thunder - ANSWER 750 mph X 1 hour/3600 sec = .2 mi/sec
--> 1 mi/5 sec
initial strike - ANSWER - high frequency and high amplitude
- loud, high pitched crack
echo - ANSWER - low frequency and low amplitude
- quieter, low pitched rumble, lightning farther away
heat lightning - ANSWER - a flash of lightning that is seen but not heard
- lighting from a distant t-storm that flashes across the sky but is not heard
Cumulonimbus clouds - ANSWER - develops vertically
- contain lightning and thunder
thunderstorm season - ANSWER March - September, can happen any time of
year
problems of thunderstorms - ANSWER - Human life loss: 200+ deaths per
year (10 year)
Complete Solution
Lightning: 50 year average (in US) - ANSWER ~600 struck per year
~60 die per year
Lightning: 10 year average (in US) - ANSWER 30 die per year
Cost of Lightning in US per year - ANSWER $4-5 billion
Lightning basics - ANSWER - Lightning=electrical discharge
- Contains 1+ billion volts, 30,000+ amps
- Length = typically about 5 km long
- Width = 1 inch (2-3 cm)
- 100 strikes per second on earth
- 9 million per day
- Temp = 30,000 degrees C (5 times hotter than the surface of the sun)
How does a cloud become electrified? - ANSWER the negative charges move
up to the positive charges building up at the top of the cloud
in order for a cloud to produce lightning, it must contain... - ANSWER ice
4 types of lightning stokes - ANSWER 1) intra-cloud
2) cloud to cloud
,3) cloud to air
4) cloud to ground
Types 1-3 makes up 80% of lightning strokes
Type 4 makes up 20% of lightning strokes
The negative Polarity Lightning strike - ANSWER ~95% of all
cloud-to-ground strikes
Steps of the negative polarity lightning strike - ANSWER 1) stepped leader
2) when they meet = return stroke
3) return strike opens an "ionized path"
4) when it meets the positive charge = second return stroke
stepped leader - ANSWER - electrons come down from cloud base searching
for a path of least resistance to a positive charge
- fork-like patter
- traveling spark of positive charge moves up to meet it
- can barely see any of this
when they meet = return stroke - ANSWER - electrons from cloud base
suddenly rush down the open path
- current travels back up producing the bright flash
- heats air to 30,000 degrees C
return stroke opens an "ionized path" - ANSWER - any left over electrons
from cloud base can then rush back down the same path
, - called the "dart leader"
when the "ionized path" meets the positive charge = second return stroke -
ANSWER - second bright flash
- can occur multiple times
Thunder - ANSWER the lightning heats the air around the bolt to 30,000
degrees C
-> the air rapidly expands, creating a huge pressure surge
math equation of thunder - ANSWER 750 mph X 1 hour/3600 sec = .2 mi/sec
--> 1 mi/5 sec
initial strike - ANSWER - high frequency and high amplitude
- loud, high pitched crack
echo - ANSWER - low frequency and low amplitude
- quieter, low pitched rumble, lightning farther away
heat lightning - ANSWER - a flash of lightning that is seen but not heard
- lighting from a distant t-storm that flashes across the sky but is not heard
Cumulonimbus clouds - ANSWER - develops vertically
- contain lightning and thunder
thunderstorm season - ANSWER March - September, can happen any time of
year
problems of thunderstorms - ANSWER - Human life loss: 200+ deaths per
year (10 year)
