GASES: a volcano and a lake killed a village of people in Africa (VIDEO)

What will happen if you put 2 pounds of dry ice into a sink of water?

https://www.youtube.com/watch?v=vPhZzsAgc7Q

Go here       This could be for Week 2 Labs (a "wow" factor with dry ice)

http://tinyurl.com/sungaskilledvillage

LESSON PLAN FROM CPALMS

A remarkable video that demonstrates the power of carbon dioxide

Keywords: gas, gas pressure, temperature, compression, concentration, 

kinetic molecular theory, 

diffusion, 

intramolecular forces, 

combined gas law, gas solubility, Henry’s law, density

Facts About Carbon Dioxide Gas:

You can’t see it or smell it.   It’s a gas that we breathe every day.   In small doses, carbon dioxide is harmless, but in high concentrations, it can be fatal.   Why???

• There is a small amount of carbon dioxide in the air we breathe everyday (makes up only 0.039% of the atmosphere).  The rest of the atmospheric air is predominantly nitrogen (80%) and oxygen (20%).
• Four percent of the air we breathe out is CO₂ as compared to the 0.039% we breathed in.  We also only use about 4% of the oxygen we breathe in, so we exhale about 16% oxygen.  Nitrogen is not used by our bodies so we breathe out the same amount breathed in (80%). 
• Carbon dioxide is odorless and is denser than oxygen.  Oxygen is easily displaced in the presence of carbon dioxide.
• Breathing 1% concentration of CO₂ can cause drowsiness with prolonged exposure.  At 2% it is mildly narcotic and causes increased blood pressure and pulse rate.  At concentrations above about five or six percent, CO₂ acts as a sensory hallucinogen, meaning you smell things and feel things that aren’t really there.  Unconsciousness quickly follows.
• Hyperventilation can cause death because the person breathes so shallowly that no oxygen enters the lung and CO₂ levels increase to dangerous amounts within the body.  A paper bag helps slow your breathing, which in turn, allows the person to take deeper breaths thereby allowing oxygen back into the lungs.
• Carbon monoxide is another colorless and odorless gas.  It has similar effects on the body as carbon dioxide, which is why many people fall asleep and subsequently die from asphyxiation.

Follow-up Questions

1.     If you breathe out CO₂, then why is it possible to resuscitate someone using mouth-to-mouth breathing?  Be specific.  Using the same logic, why do you blow on a fire to get it going?

2.     Propane is another gas denser than air.  Why should you NEVER “stop, drop, and roll” if you catch on fire near a BBQ grill?

3.     Helium is less dense than air.  Your vocal cords vibrate at a higher frequency when less dense air moves across them, which is why your voice sounds like a chipmunk after inhaling it.  What would your voice sound like if you inhaled carbon dioxide?  Explain.

4.     Most soda tastes ‘flat’ while being in the fridge.  Why is this so?  If you were to allow a cool beverage from the fridge to warm up to room temperature, would it taste any differently?  Explain why or why not.

5.     Why does soda fizz up as soon as you uncap the bottle?  Hint: this is the same phenomena that occurred at Lake Nyos.

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FOR THE TEACHER (but some students can read the steps below and help move the class along)

A FOLLOW UP LAB with Carbon Dioxide (DRY ICE)

The cost is about $10 for the dry ice

QUIZ

1.An opened Coke bottle at room temperature will have (more, less, the same) carbon dioxide in the gas space above the liquid than an ice cold bottle.

2.The amount of dissolved oxygen in a mountain lake at 10,000 ft and 50oF is (greater, lesser, the same) than the amount of dissolved oxygen in a lake near sea level at 50oF

3.Champagne continues to ferment in the bottle. The fermentation produces CO2. Why is the cork wired on a bottle of champagne?

4.Thermal pollution is merely waste heat that has been transferred to water or air. Aquatic life can die from thermal pollution.  The concentration of dissolved oxygen in water (increases, decreases, is unaffected) by thermal pollution. 

5.What 2 factors allow carbon dioxide to dissolve easily in water?  Be specific.

ANSWERS 

1.More

2.Lesser

3.More gas is produced and builds up gas pressure over time

4.Decreases

5.Low temperature; high pressure

• Lesson Plan Template: 

  Confirmatory or Structured Inquiry

• Learning Objectives: What will students know and be able to do as a result of this lesson?

  
  Students will be able to explain what determines the density of a substance. Students will be able to predict the behavior of a gas relative to air using density.
  
  Students will be able to explain how a substance can change state and discuss what factors affect state change.
  
  Students will be able to predict the conditions under which gases can be dissolved in water.
  
  Students will be able to explain, using the kinetic molecular theory, why gases expand or contract with varying temperature and pressure. Students will predict the behavior of gases under varying conditions of temperature and pressure.
  
  Students will be able to discuss the relative density (high or low), relative boiling point (high or low) and relative intermolecular forces (high or low) of a given substance based on its boiling point and other witnessed gas behavior.
  
  Students will be able to explain gas pressure in terms of the kinetic theory, and relate temperature and average kinetic energy of particles of a gas.
  
  Students should be able to recognize that the factors increasing the solubility of solids actually decrease the solubility of gases (inverse relationship between solubility of gases vs solubility of solids).

• Prior Knowledge: What prior knowledge should students have for this lesson?

  
  Students should be familiar with the factors that affect the physical state of a substance.
  
  Students should know the characteristics that distinguish gases, liquids and solids.
  
  Students should be able to explain density.
  
  Students should know that some things dissolve in water and others do not. Students should be able to briefly discuss what factors affect the solubility of solids (think of how you would dissolve sugar easily in water).
  
  Students should recognize that gases are compressible.
  
  Students should know that particles of matter are in constant random motion.
  
  Students need to be familiar with particle motion being influenced by temperature or pressure.
  
  Students should know that gases travel from areas of high pressure to areas of low pressure.
  
  This prior knowledge will be assessed through preliminary questions as well as through open discussion of the material.

• Guiding Questions: What are the guiding questions for this lesson?

  
  Why does an air balloon rise? Ans: Warmer air is less dense than cooler air. Less dense air in the balloon will cause it to rise.
  
  Why do you have to boil pasta for a longer duration at high altitudes? Ans: Less air pressure pushing down on the water makes it easier to boil. However, the boiling water is now at a lower than normal temperature, so the pasta requires a longer cook time to offset the lower boiling temperature.
  
  Why does an inflated balloon shrink in the freezer? Ans: The cooler temperature slows gas particle movement. With less movement, there are fewer particle collisions, thus lowering the pressure inside the balloon relative to the outside air pressure. Subsequently, the balloon shrinks. The opposite is true if the balloon were put in boiling water.
  
  Why is propane, normally a gas at room temperature, a liquid (as evidenced when you shake the canister) inside your grill's tank? Ans: The propane is under extreme pressure. The particles are much closer together, thereby increasing attractive forces between particles. The chain of these events causes the gas to condense into a liquid.

• Introduction: How will the teacher introduce the lesson to the students? 

  
  Script: "Every time you burp, you release carbon dioxide. Imagine if one burp released enough carbon dioxide to suffocate an entire town. Is this possible? The tragedy at Lake Nyos suggests, 'yes'."
  
  To demonstrate the differences in gas behavior, the teacher can place dry ice on the lab table. Students should notice immediately that the solid becomes a gas. Students should be able to infer that carbon dioxide has a very low boiling point (as evidenced by how cold it must be to be a solid AND how easily it becomes a gas at room temperature. Students should witness how dense carbon dioxide is based on how it flows downward off the lab bench. Finally, if the teacher places a piece of dry ice in a beaker of water, the students will be able to witness first hand the "burping" that Lake Nyos underwent.
  
  Nyos provides a memorable introduction to the concept that water contains dissolved gases, and under certain conditions, those gases can escape.

• Investigate: What question(s) will students be investigating? What process will students follow to collect information that can be used to answer the question(s)?

  
  How do gases behave (solubility, diffusion, density, volume, etc.) under different conditions?
  
  The students will follow a structured inquiry activity to recognize that density, intermolecular forces, pressure and temperature all affect how a gas behaves.

• Analyze: How will students organize and interpret the data collected during the investigation?

  
  Through class discussion, the students will be able to explain the mechanisms governing the behavior of everyday gases (weather balloon, carbonated beverages, aerosol products, etc.).
  
  Through the reading exercise and lab activity, the students will be able to explain the factors affecting gas behavior in the everyday environment.

• Closure: What will the teacher do to bring the lesson to a close? How will the students make sense of the investigation?

  
  As a summary explanation of the events that unfolded at Lake Nyos in 1986, the class will watch a brief video (3.5 min) of the tragedy at Lake Nyos. The teacher will then proceed to give the "exit" quiz; upon completion, the answers to the quiz will be reviewed to ensure understanding.

• Summative Assessment

  
  Each group will be responsible for handing in a "lab report" with a record of their findings and answers to the questions. A short quiz involving free response and multiple choice questions will be administered to assess the individual's understanding of the material.

• Formative Assessment

  
  After engaging the students with a brief video of the tragedy at Lake Nyos, the students will divide themselves into five groups of five. Their task is to answer one question from the formative list of topics given by the teacher. The topics will be assigned randomly by the teacher. To aid with the discussion, a list of factual information relevant to the topic will be provided. Each group will then discuss the topic among themselves, answer the posed question using prior knowledge and the facts provided, and finally present their findings to the class. In this fashion, the teacher can asses each group's general strengths and weaknesses regarding the topic of gases and their properties. In addition, each group will strengthen their understanding by listening to the other presentations.

• Feedback to Students

  
  Immediate feedback will be given by the teacher to each group after their presentations to the class. Following presentations, each student will individually read a literary piece on the tragedy at Lake Nyos. A list of key concepts will be listed on the board to help guide the students in their reading. The goal during reading is for each student to be able to cite five key facts regarding the cause and effect of the disaster.
  
  The teacher will ask pointed questions regarding the key concepts from the reading. For each question by the teacher, students will hold up a white board with their answer above their heads (while looking straight ahead). In this fashion, the teacher can appreciate the scope to which students know the necessary backgroundinformation for the day's activity, and students will NOT be able to see each other's answers.
  
  The day's lab activity will be closely observed and monitored by the teacher. Members of the same group will cooperate to record all necessary information, as well as answer all follow-up questions regarding the lab activity. During this time, all students will have a chance to confirm with the teacher their findings and answers to the lab questions.

ACCOMMODATIONS & RECOMMENDATIONS

• 
  

  Accommodations: 

  Students will be given accommodations according to their Individualized Education Program (IEP) or 504 Plan. Auditory and visually impaired students will be placed in the front of the class with direct line of sight to the teacher. Students with emotional impairments will be given the opportunity to work independently or on an alternative assignment which would still cover and explain the pertaining material. ESOL students will be paired with a peer to check their work; they will also be given extended time to complete assignments and/or tasks. In addition, any student will be given a visual representation of the notes/instructions/lesson plan if requested.
• 
  

  Extensions: 

  This lesson could be extended to include the investigation of the density of solids, liquids and gases. An inquiry activity could compare the densities of various solids (ice, salt, aluminum, iron, cork) as compared to various liquids (water, alcohol, corn syrup, corn oil). Students could record the properties of each sample and comment on intermolecular forces, boiling point, solubility, etc.
  
  A further extension could incorporate the observation of gases such as helium, sulfur hexafluoride (video illustration only), and propane (video illustration only). Each has its own unique characteristics and behavior at normal room temperature and pressure.
• 
  Suggested Technology: Computer for Presenter, Internet Connection, LCD Projector, Speakers/Headphones, Adobe Flash Player, Microsoft Office, Computer Media Player, Java Plugin
• 
  

  Special Materials Needed:

  tea light candles: 2 per group of five students
  
  metal trough or shallow tray
  
  baking soda
  
  vinegar 
  
  1 Lg beakers (for baking soda)
  
  1 100 mL graduated cylinder (for vinegar)
  
  long stem lighter (teacher only)
  
  tracing paper: 1 sheet per group of five students
• 
  

  Further Recommendations: 

  Demonstrate the behavior of carbon dioxide visually by putting dry ice out onto a lab table. Proceed to put it in water. Proceed to put a tiny bit into a balloon, and then tie off. Another demonstration regarding density of substances can be performed using dyed alcohol, dyed corn syrup and water. If each of the dyed liquids is slowly poured into a beaker filled with the water, a series of layers will form. These layers will stay separated indefinitely unless the conditions are disturbed: stirring or heating. One could relate the trigger of events at Lake Nyos to be similar to disrupting the balance of the layers in the beaker.

Additional Information/Instructions

By Author/Submitter
Dry ice sublimes quickly. Be sure to purchase as close to the day of activity as possible. Store in a well insulated styrofoam container (not air tight!). Be sure dry ice sample is tightly wrapped in newspaper. Use gloves when handling. Most meat departments in supermarkets sell dry ice.

Use tea lights having an aluminum housing (not plastic...plastic melts giving off toxic fumes!). 

Contributed by: Bryan Wilk

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TOO MUCH READING

How did Lake Nyos suddenly kill 1,700 people?

by Susan L. Nasr

Citation:

Nasr, Susan L..  "How did Lake Nyos suddenly kill 1,700 people?"  24 March 2009.  HowStuffWorks.com. <http://science.howstuffworks.com/environmental/earth/geophysics/lake-nyos.htm>  07 July 2012.

Lake Nyos had long been quiet before it happened. Farmers and migratory herders in the West African country of Cameroon knew the lake as large, still and blue.

But on the evening of Aug. 21, 1986, farmers living near the lake heard rumbling. At the same time, a frothy spray shot hundreds of feet out of the lake, and a white cloud collected over the water. From the gro­und, the cloud grew to 328 feet (100 meters) tall and flowed across the land. When farmers near the lake left their houses to investigate the noise, they lost consciousness.

The heavy cloud sunk into a valley, which channeled it into settlements. People in the affected areas collapsed in their tracks -- at home, on roads or in the field -- losing consciousness or dying in a few breaths. In Nyos an­d Kam, the first villages hit by the cloud, everyone but four inhabitants on high ground died.

The valley split, and the cloud followed, killing people up to 15.5 miles (25 kilometers) away from the lake. Over the next two days, people from surrounding areas entered the valley to find the bodies of humans and cows lying on the ground.

By Aug. 23, the cloud had mostly blown away, and the silence had lifted. After being unconscious for up to 36 hours, some people revived to find, horrifically, that their family members, neighbors and livestock were dead.

The lake had changed, too. It was now shallower; plants and leaves floated in it; and its formerly picturesque blue hue had darkened into rust. What was the deadly force at Nyos?  

Investigating the Nyos Disaster

Scientists soon learned that the cloud contained carbon diox­ide (CO₂). That finding explained the cloud's heaviness, since CO₂ is denser than air. The cloud was actually CO₂ mixed with air. The CO₂ killed directly by shutting off people's consciousness and breathing. When the CO₂ concentration was 15 percent or less, people lost consciousness and later revived. Individuals who inhaled more than 15 percent CO₂ stopped breathing in minutes and died.

As for why the lake ejected CO₂ -- up to a third of a cubic mile of it -- scientists disagreed. One camp believed a volcanic eruption released CO₂ and blew up the lake. Another camp thought CO₂ was gradually leaking into and being stored in the lake. When the lake exploded, it released the gas in a gigantic, deadly burp.

"While the two camps of scientists were fighting, they agreed that CO₂ killed the people, and the people would be safer on higher ground," says William Evans, a geochemist with the U.S. Geological Survey who investigated the disaster. The Cameroonian government acted accordingly.

Evans' team installed CO₂ monitors on the lakeshore. The monitors were hooked to sirens that would sound if too much CO₂ entered the air. People knew the alarms meant they should go to high ground.

As years passed, scientists resolved the debate about the origin of the CO₂. After measuring gas at the bottom of Lake Nyos, they found a CO₂-rich layer, where levels of the gas were rising over time, suggesting gradual leakage into the bottom of the lake.

Scientists looked for markers of a volcanic eruption, such as sulfur and chloride in the lake. They also installed seismometers around the body of water to record tiny earthquakes that would follow a volcanic eruption. "It was the quietest area that the British Geological Survey had ever monitored," says Evans. The volcano hypothesis died. CO₂ was bubbling into the lake from below.

Scientists reasoned that CO₂ had been trapped in the bottom of Lake Nyos for a long time, held down by 682 feet (208 meters) of water. On the day of the eruption, however, something external triggered the release of gas. Most likely, it was a rockslide from one of the lake's walls. When the falling rocks sunk to the bottom of the lake, they pushed up some gas. Then most of the gas bubbled up.

If this sounds like a freak occurrence to you, read on to learn about the lake that exploded in an eerily similar fashion just two years before.

Lake Monoun and Other Exploding Lakes

Almost two years earlier, on the evening of Aug. 15, 1984, Cameroonians about 62 miles (100 kilometers) southeast of Nyos had heard similar rumblings near a lake. The site of this prior explosion, however, was the smaller Lake Monoun. Around 11:30 p.m., CO₂ shot out of the lake and sunk into a valley, near a road. As people from the nearby village of Njindoun walked down the road on their way to work before dawn, they entered the cloud, collapsed and died.

By 10:30 a.m. or so, wind had swept the cloud away. A doctor and police officer arrived on the scene to find most of the 37 dead on a short stretch of road, including a man slumped over his motorcycle [source: Sigurdsson].

The Cameroonian government suspected the explosion was an act of terrorism or the result of someone dumping chemicals into the lake. More traditional villagers in Njindoun believed legends that evil spirits periodically left the lake and killed neighboring people. "Probably these legends came about because of gas bursts in the past," says Evans.

Another lake in Africa may be building toward a burst. Lake Kivu, situated between Rwanda and the Congo in the African Rift Valley, is a legitimate worry. It's more than twice as deep as Nyos and can store more gas. Bacteria in the lake are chugging out methane, and CO₂ is leaking in from magma below. Sediment layers suggest the lake may have erupted 7,000 to 8,000 years ago, says Varekamp. Because 2 million people live near Kivu, the lake's gas pressure is being monitored. "If that ever were to go, that would be a natural disaster on a scale we haven't seen, except for the tsunamis in 2004," says Varekamp.

There's also Lake Quilotoa in Ecuador, which is rich in CO₂, deep and in a tropical climate. "Some scientists consider it a potential analog of Nyos," says Varekamp.

You may be wondering whether any lake can explode. Could it happen to the pond in your backyard? Let's return to our historic lakes to find out.

Recipe for a Killer Lake

Exploding lakes are rare, and the backstories of Lakes Nyos and Monoun explain why. In Cameroon, there are weak spots in the Earth's crust at which magma, or liquid rock, rises from the Earth's mantle. The magma shoots up quickly and vertically, cutting a tube toward the surface. If it reaches the surface, the magma may spurt out and rain a big pile of rock, depositing a cinder cone volcano.

If the magma hits wet rock as it rises, it explodes, blasting a crater in the ground. More than 18,000 years ago, such a blast formed the crater at Lake Monoun [source: Sigurdsson]. A si­milar blast happened a few hundred years ago to form Nyos [source: ­Kling]. Water filled the craters, and they became lakes.

At the bottom of each lake, the old tube where magma first rose to the surface remains. If you follow the tube some 3 to 6 miles (5 to 10 kilometers) down, you'll hit magma. The pressure down there forces out one of the most abundant gases in liquid rock: CO₂. The gas rises up the tube into the lake. Researchers have identified more than 100 places in Cameroon where CO₂ leaks in large, but not dangerous quantities out of the ground, says Evans.

Several factors -- not just CO₂ -- have to align to create an exploding lake. First, the lake must be deep. When little water holds down the gaseous bottom water, the lake needs only a small disturbance -- wind -- to release the gas. In deep lakes, the overlaying water acts as a cork in a champagne bottle. Every 10 meters (33 feet) of water adds 1 atmosphere of pressure, so in a 100-meter (328-foot) lake, 10 atmospheres of pressure hold down the gas at the bottom, says Evans. Wind can't stir it up.

Second, the climate must be stable all year, which is why exploding lakes cluster in the tropics. Lake Superior in the United States, for instance, charges with gas from decaying matter until the season changes. Every fall, the lake's surface cools and gets denser, then sinks to the bottom. The gaseous bottom water rises. The lake turns over, or exhales -- most lakes do at least once a year, says Varekamp. In places where it's warm or cold year-round, lake layers hold their temperature and position. Third, it takes a trigger like a landslide, earthquake or too much gas to unsettle the gas layer.

Cameroon has all the right ingredients for exploding lakes: magma releasing CO₂­ into deep lakes, a tropical climate and a trigger.

Degassing Lakes with Big Straws

After Lake Nyos burst, an international team began discussing ways to degas bot­h lakes and avert future disasters. They talked about bombing the lakes to blow out the gas. But scientists worried a bomb would also blow out one of Lake Nyos's walls, causing an enormous flood. "That would be a disaster in its own right," says Evans. As early as November 1986, French scientists proposed a pipe.

"The pipe idea won out because it's simple, and there's not much risk associated with it," says Evans. "You could eliminate the gas in a controlled fashion."

Pipes were slow to be installed. Money and roads into Nyos weren't plentiful. "When we left Cameroon in 1986, we were certain that we had done good science, recommended how to fix the problem and said aid groups will come in next week and start piping the gas out. It was a wake-up call for all of us for how long this type of stuff takes," says Evans.

The first pipe went into Lake Nyos in 2001. A French engineering team sunk a 6-inch (15-centimeter) plastic tube 666 feet (203 meters) into the lake until it reached the gas layer [source: Halbwachs]. Again, froth shot out like champagne from an uncorked bottle, but this time it wasn't a deadly surprise.

Today, Nyos is degassed to about 80 percent of the level after the 1986 explosion, says Evans. "The lake is safer today than it was in 2000, but it is still hazardous." A big enough input of energy, like a large earthquake or a landslide, could cause the lake to erupt, he says.

Another problem is Nyos' weak wall. "That natural dam could rupture any day," says Evans. "If the dam were to suddenly fail, the upper 40 meters [131 feet] of the lake would empty in a huge flood, and that would release the pressure on the gas remaining in the deep water. You could have a combination of a flood and a gas release." Evans says the gas should be piped out as soon as possible, and then the wall should be fixed. Two more pipes are planned, with the first possibly going in in spring 2009.

Lake Monoun has three pipes: one installed in 2003 and two in 2006. "Another eruption is probably not possible there, given that the lake is almost completely degassed," says Evans. "Monoun now would be a very nice place to live."

So the next time ­you smell the sulfurous gas as your local lake turns over, think of it as a lake exhalation -- and be thankful that it's not a burp.

Sources

·       Barberi et al. "The Gas Cloud at Lake Nyos (Cameroon, 1986): Results of the Italian Technical Mission." Journal of Volcanology and Geothermal Research. Vol. 39, no. 2-3, 1989.

·       Evans, William. Personal interview. Conducted 2/27/2009.

·       Halbwachs et al. "Lake Nyos Degassing Project: First Results Pertaining to the Degassing Under Way." European Geophysical Society XXVII General Assembly. April 2002. (3/19/2009)http://adsabs.harvard.edu/abs/2002EGSGA..27.6051H

·       Kling, George W. et al. "The 1986 Lake Nyos Gas Disaster in Cameroon, West Africa." Science. Vol. 236. no. 4798. April 10. 1987.

·       Sigurdsson, H. et al. "Origin of the Lethal Gas Burst from Lake Monoun, Cameroun." Journal of Volcanology and Geothermal Research. Vol. 31. no. 1-2. 1987.

·       Varekamp, Johan. Personal interview. Conducted 3/5/2009.

=============================  

LAKE NYOS PRE-LABORATORY ACTIVITY

1.  This is a map of Lake Nyos and the surrounding area.  **Trace** the picture below and complete the topographic map by creating contour lines (connect identical numbered elevations by a line). Start at 91 meters and work your way outward.  

2.     Using the letters (A, B, C) marked on the map, what is the highest point and what is the lowest point?  Which direction would cool air travel?  Explain why cool air would travel in this fashion.  Hint: cool air behaves differently than warm air. 

3.      Why are no gas bubbles visible when a soda bottle is unopened?  Explain why the eruption at Lake Nyos is similar to the opening a bottle of soda. 

4.      Air has a density of approximately 1.2 kg/m³ where as carbon dioxide (CO₂) has a density of 1.98 kg/m³.   If both gases were put into a glass, which gas would be on the bottom and which would be on the top of the glass?  Explain your answer.

    

       5.   The people and animals in the villages surrounding Lake Nyos died by asphyxiation, which means they suffocated to death.   By looking at your topographic map that you made and knowing the density of carbon dioxide, explain why the village was the hardest hit.  

STANDARDS
SC.912.N.1.1 :Define a problem based on a specific body of knowledge, for example: biology, chemistry, physics, and earth/space science, and do the following:

Pose questions about the natural world, (Articulate the purpose of the investigation and identify the relevant scientific concepts).

• SC.912.N.1.1 :Define a problem based on a specific  body of knowledge, for example: biology, chemistry, physics, and earth/space science, and do the following:  
  
  1. Pose questions about the natural world, (Articulate the purpose of the investigation and identify the relevant scientific concepts).
  2. Conduct systematic observations, (Write procedures that are clear and replicable. Identify observables and examine relationships between test (independent) variable and outcome (dependent) variable. Employ appropriate methods for accurate and consistent observations; conduct and record measurements at appropriate levels of precision. Follow safety guidelines).
  3. Examine books and other sources of information to see what is already known,
  4. Review what is known in light of empirical evidence, (Examine whether available empirical evidence can be interpreted in terms of existing knowledge and models, and if not, modify or develop new models).
  5. Plan investigations, (Design and evaluate a scientific investigation).
  6. Use tools to gather, analyze, and interpret data (this includes the use of measurement in metric and other systems, and also the generation and interpretation of graphical representations of data, including data tables and graphs), (Collect data or evidence in an organized way. Properly use instruments, equipment, and materials (e.g., scales, probeware, meter sticks, microscopes, computers) including set-up, calibration, technique, maintenance, and storage).
  7. Pose answers, explanations, or descriptions of events,
  8. Generate explanations that explicate or describe natural phenomena (inferences),
  9. Use appropriate evidence and reasoning to justify these explanations to others,
  10. Communicate results of scientific investigations, and
  11. Evaluate the merits of the explanations produced by others.