Transcript What happened at Lake Nyos?

What happened at
Lake Nyos?
A SCIENTIFIC
INVESTIGATION
A Beautiful Lake
Cameroon, Africa – August 26, 1986
The Story
 On the evening of August 26, 1986, without
warning, 1,700 people and 6,000 head of
livestock died near Lake Nyos, in Cameroon,
Africa without any signs of violence.
 1987, 37 people died at nearby Lake
Monoun.
 Is there a pattern?
The Legend
 Local folklore around Lake Nyos tells of a king who
hanged himself after being fooled by the leader of an
enemy tribe. According to the legend, the king’s
body formed a lake that later exploded, killing many
members of the rival tribe.
 Is there a scientific explanation for what happened at
Lake Nyos?
 Take 5 minutes and brainstorm what you think may
have caused these tragedies.
The findings of the response team
 Testing of the lake water revealed dissolved gases at
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a higher than normal rate.
Undisturbed lake bottom – no evidence of volcanic
eruption
Both incidents occurred in August (previous
incidents didn’t have a documented date)
Previous volcanic history in the area.
Killer Video
The Cause
 Killer Video
 Trapped gases in the bottom of the lake were
released in a large quantity.
 Possible causes of the pressure change that produced
this are:
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Heavy rain
Strong winds
Earth tremor
Landslide
Seasonal changes
 How Do We Convince The Government & United
Nations that this is the actual cause?????
Scientific Design Process
 GATHER INFORMATION: Describe the information needed and how to
collect that information.
 EXPLORE IDEAS: Describe several ideas including any useful scientific
concepts.
 PLAN SUMMARY: Write a summary of the plan including reasons for
choosing this solution.
 STEPS TO DO THE PLAN: Write the steps, including all materials used in
the Plan Summary and in the Diagram of Solution.
 DIAGRAM OF SOLUTION: Make a labeled diagram
 TEST SOLUTION: Describe the process to measure or observe how well
this solution may solver the problem
Scientific Method
 Lake Nyos Question –
 What Caused the deaths of all the people??
 Lake Nyos Hypothesis
 Trapped gases in the bottom of the lake were released in a
large quantity.
Your Task  The Government, UN & Public are skeptical that this
could actually happen.
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We need to convince the UN & Public that death by a giant bubble of
CO2 being released is possible
 Write a Hypothesis answering the experimental
question:
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Question –
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Can enough gas be produced to “snuff” out candles “below” the lake?
 Write a procedure to test your hypothesis
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Should provide evidence that released gases could in fact kill this
many people.
Manipulated Variable =
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Ratio of Vinegar to Baking Soda
Experiment
 Materials Available to
You:
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Baking Soda
Vinegar
Candles
“Hill”
Lighter
 Variables to think about
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Distance candles are…
Height of candles
Amount of Baking soda
Amount of Vinegar
 Manipulated Variable:
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Ratio of Vinegar to Baking
Soda
Experiment
On Monday:
1. Run the experiment you have designed once
approved by the teacher.
2. If you change your procedure design during the
process, include it in your lab notebooks.
3. Compile the data then analyze the data with your
group/then the class.
Lake Nyos
DAY 2
Follow up Questions
Find the atomic mass of each of the following gases:
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N2 (nitrogen gas)
O2 (oxygen gas)
CO2 (carbon dioxide)
NH3 (ammonia)
C3H8 (propone)
What gas was produced by the mixing of Vinegar and
Baking Soda? What kind of reaction was it?
What solutions to prevent this in the future did your group
come up with?
What are the steps of the scientific method?
What would your group recommend from your findings?
How did this compare to real life scientific testing method?