Presentation on theme: "Studying Ozone and Air Quality Steve Schneider Deborah Carlisle."— Presentation transcript:
Studying Ozone and Air Quality Steve Schneider Deborah Carlisle
Measuring Ground-level Ozone VOCs + NO X + sunlight O 3 Motor vehicles are the single largest contributor to ground- level ozone.
Measuring Ground-level Ozone O 3 levels above 120 ppb are considered unhealthy. They can be generated by some electrical equipment or from photochemical reactions with smog: VOCs + NO X + sunlight O 3 Motor vehicles are the single largest contributor to ground-level ozone. In this project we are adapting the relatively easy-to-make Schoenbein papers for classroom use, and using ADI to analyze the color changes quantitatively.
Commercial Papers: Ecobadge, Ozone badge
Findings: Commercial cards had significant variability and were expensive. Researched making Schoenbein papers Inexpensive and safe to make
Schoenbein Papers Ozone was discovered by C.F. Schoenbein in He developed an ozone-sensitive test paper that was widely used historically, and more recently in classrooms. The standard protocol for using the papers calls for an 8-hour exposure to the air out of direct sunlight. Various studies have shown a dependence on humidity, and there are a variety of recommendations for moistening the strips prior to exposure. Control low O 3 high O 3 exposure exposure
History Despite the method's early limitations, starting in the mid-1800s, more than 300 stations recorded ozone exposures in countries such as Austria, Australia, Belgium, England, France, Germany, Russia, and the United States.
Learning Goals : Analyze different relative amounts of ozone found in various locations using test results. Understand that ozone is found near the earths surface (ground level) in the troposphere as well as the stratosphere. Understand that ozone test strips/Schoenbien paper detect ozone gas through a chemical reaction that is caused by ozone in the air. Use technology to more precisely analyze relative color changes obtained with ozone test strips.
Some Testing Ideas: Test for ozone at different times of day and look for patterns. When are ozone concentrations the highest? Test for ozone in various locations and see what areas are the highest. Look at the effects of wind patterns on ozone Students research and brainstorm where ozone might be found and what equipment/machines produce ozone
Making Schoenbein Papers
Classroom Use Made Easier: 1. Test strips can be stored in a double plastic zip lock bag, until you are ready to read your results. 2. To look at results simply dip your exposed test strip in a beaker of water. You will see a visible color change. 3. Compare the relative colors to the control. 4. Use digital analysis to measure RGB values and compare between test strips.
Testing Ozone Levels Groups of 4 Select a test site Things to Consider Avoid direct sunlight Free air circulation around your strip Run a control with your group Label an index card with date/time/location
Carrying Out the Experiment: Discuss experimental design in your groups to come up with a plan for testing Run tests (place test strips and control) Collect test strips and place in zip-lock baggies Return to lab and expose strips by dipping in water Photograph test strips Data Analysis and share results
How do Ozone Test Strips Work? Ozone is a strong oxidizer. It rapidly reacts with the iodide ion, I - in the KI salt applied to the filter paper. KI + H 2 O + O 3 I 2 + O 2 + K + I 2 + I - + starch I starch Last step : I 3 - (linear)+ starch (helix) (Turns Blue) Combination of I 3 - and helix causes light reflection to be in the blue/violet range of visible spectrum
Schoenbein Papers Cntrl
Comparing Test Strips
Calibration of Test Strips
National Science Education Standards Science as Inquiry: Grades 5-8 and 9-12 Ability to perform scientific inquiry, understanding about scientific inquiry Science and Technology: Grades 5-8 and 9-12 Understanding about science and technology Science in Personal & Social Perspectives: Grades 9-12 Environmental quality, changes in environments