Exhaust, Gas and Pollution

Standard V

Students will understand that Earth's atmosphere interacts with and is altered by the lithosphere, hydrosphere, and biosphere.

Objective 01

Describe how matter in the atmosphere cycles through other Earth Systems.

Indicator c

Interpret evidence suggesting that humans are influencing the carbon cycle.

Intended Learning Outcomes:

  1. Use Science Process and Thinking Skills
    1. Observe objects, events and patterns and record both qualitative and quantitative information.
    2. Use comparisons to help understand observations and phenomena.
    3. Plan and conduct experiments in which students may:
      • Identify a problem.
      • Formulate research questions and hypotheses.
      • Predict results of investigations based upon prior data.
      • Identify variables and describe the relationships between them.
      • Plan procedures to control independent variables.
      • Collect data on the dependent variable(s).
      • Select the appropriate format (e.g., graph, chart, diagram) and use it to summarize the data obtained.
      • Analyze data, check it for accuracy and construct reasonable conclusions.
      • Prepare written and oral reports of investigations.
    4. Distinguish between factual statements and inferences.
  2. Manifest Scientific Attitudes and Interests
    1. Accept responsibility for actively helping to resolve social, ethical and ecological problems related to science and technology.
    2. Evaluate scientifically related claims against available evidence.
  3. Demonstrate Understanding of Science Concepts, Principles and Systems
    1. Know and explain science information specified for the subject being studied.
  4. Communicate Effectively Using Science Language and Reasoning
    1. Provide relevant data to support their inferences and conclusions.
    2. Use precise scientific language in oral and written communication.
    3. Use proper English in oral and written reports.
  5. Demonstrate Awareness of Social and Historical Aspects of Science
    1. Cite examples of how science affects human life.
  6. Demonstrate Understanding of the Nature of Science
    1. Understand that science and technology may raise ethical issues for which science, by itself, does not provide solutions.
Summary: The teacher will demonstrate how bromthymol blue is used to indicate presence of CO2 in gas(refer to sequence below). Following this demonstration, the students will design their own experiments to test gases which are suspected of containing CO2. A variety of sources should be encouraged by the teachers (i.e. exhaust from different types of cars, smoke, cigarette smoke, wood stoves, natural gas). A variety of testing procedures should also be encouraged.

Category: Inquiry lesson

Learning Objectives:

  1. Students will isolate the sources of CO2 emissions.
  2. Students will develop investigative skills.(i.e. bromthymol blue as an indicator, development of hypothesis and experiments.)
  3. Students will discover how carbon dioxide relates to acid rain and the greenhouse effect.
  4. Students will learn the following terms: carbon dioxide, acid rain, greenhouse effect.
  5. Students will discover a cause effect relationship between fuel consumption and atmospheric polution.

Materials:

  • Pencil
  • Balloons
  • Test tubes
  • Bromthymol blue
  • String
  • Tape
  • Straws
  • Bicycle pump (can be used to inflate balloons from a smokey source).

Background:
An effective way to collect car exhaust is with a two inch, two hole rubber stopper. Tubes are inserted into the stopper. One tube is to allow the car to idle properly, the other is used to inflate balloons. Place the rubber stopper into a car that is not running. Start the car. Also, a bicycle pump is effective in collecting gas. It can be put in a smoke source, expanded, put into a balloon and compressed to inflate it.

If students have not had exposure to bromthymol blue, a bit of background may be necessary for students to put in their notes. Humans exhale nitrogen, oxygen, CO2, and water vapor. Among these things, the CO2 will react with the water to form a weak carbonic acid. This acid will cause the bromthymol blue to turn green or even yellow due to its acidic nature.

Sequence and duration of each part of lesson:
Encourage students to take notes on the following demonstration and discussion. The teacher may even choose to write ideas on the board. Instruct students that these notes will be included as part of their lab report.

This activity begins by the teacher modeling the characteristics of bromthymol blue. The teacher will mix a 5% solution of bromthymol blue/water in a test tube. This is done in front of the students so they can learn how to run their own test. The teacher inserts a straw into the test tube and begins lightly blowing into the bromthymol solution (or have a student blow), being careful not to blow too hard or the solution will spill. The solution will change colors in less than a minute. The teacher then asks the students inquiry questions such as:

Why did it change color?
What makes it change color?
Could there be something in my breath that causes it?
What other gasses or exhausts could cause such an effect?

After the inquiry questions, the students should be able to deduct that the cause of the color change is due to the presence of CO2.

The teacher then should lead a discussion as to -"What harm is caused by CO2 in the atmosphere?" Answers may vary but important points should include greenhouse effect, global warming, weather patterns, effect on agriculture, pollution, acid rain.

The teacher should then ask,"What are major causes of CO2?" Answers may vary but should include automobiles, factories, animals, coal fire generation etc.

A challenge to the students is then issued by the teacher. The students are to:

  1. Select and collect a gas or exhaust by any means they can develop (encourage the use of balloons.)
  2. Design an experiment to test for CO2 or other acid causing emissions. This experiment must be pre approved by the teacher to ensure safety. This experiment must in include a hypothesis about their chosen gas as to whether it contains CO2 or other potentially acidic properties.
  3. The experiment should also include a lab report which includes:
    • Pre-lab notes
    • Title
    • Hypothesis
    • Procedure
    • Materials
    • Data
    • Conclusion
    • Peer review
  4. Conduct the experiment.
  5. Record the results. Encourage students to be as quantitative as possible.(i.e. amount of gas collected, duration of exposure to bromthymol, concentration of bromthymol, shade of color change).
  6. Report the results to the class.
  7. Conclude by conducting a peer review in which the students compare their conclusions to classmates that tested a like product. Students should look for results that would support or contradict their own findings.

Evaluation: Rubric for evaluating the experiment.

Score
Identifying behaviors
4 The students are able to work independently on all aspects of the task. They formulate a hypothesis and run an appropriate experiment to test their hypothesis. They collect accurate data and are able to interpret data. They clearly communicate results and answer questions concerning data.
3 The students are able to work independently after minimal assistance. They formulate a hypothesis and run an appropriate experiment to test their hypothesis. They collect data and interpret with few mistakes. They are able to correct errors when pointed out, and they are knowlegable concering information.
2 The students need prompts and assistance in devolpment of an hypothesis, procedure and collecting data. The student runs an experiment but data and interpretation are subject to error. Attempts are made to correct inconsistancies.
1 Cannot complete task as assigned. The students run an experiment but has little relevance to hypotheses. The data is inacurate and there is no attempt to interpret or corect procedures.
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Updated March 18, 2005 by: Glen Westbroek

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