A SCIENTIFIC INVESTIGATION What happened at Lake Nyos?

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 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:  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.  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:  Question –  Can enough gas be produced to “snuff” out candles “below” the lake? Write a procedure to test your hypothesis  Should provide evidence that released gases could in fact kill this many people.  Manipulated Variable =  Ratio of Vinegar to Baking Soda

Experiment Materials Available to You:  Baking Soda  Vinegar  Candles  “Hill”  Lighter Variables to think about  Distance candles are…  Height of candles  Amount of Baking soda  Amount of Vinegar Manipulated Variable:  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.

DAY 2 Lake Nyos

Follow up Questions 1. Find the atomic mass of each of the following gases:  N 2 (nitrogen gas)  O 2 (oxygen gas)  CO 2 (carbon dioxide)  NH 3 (ammonia)  C 3 H 8 (propone) 2. What gas was produced by the mixing of Vinegar and Baking Soda? What kind of reaction was it? 3. What solutions to prevent this in the future did your group come up with? 4. What are the steps of the scientific method? 5. What would your group recommend from your findings? 6. How did this compare to real life scientific testing method?