Group members: Class: _________________ Period:____________ 1. 2. 3. 4. Red Lab: Humans in the Biosphere Investigating Air Pollution Problem: How can air pollution be detected? Introduction: Although life on Earth depends on air and water, we are endangering these important resources by polluting them with harmful substances. The air we breathe contains the oxygen our cells need, but it also contains many other chemicals that can damage our bodies. Our atmosphere is polluted with smog, acid rain, carbon dioxide, and a variety of other chemicals that create problems for all organisms dependent on the atmosphere. In this investigation, you will conduct tests to determine the types of pollutants present in samples of air taken from the area in which you live. Materials checked returned/date out/date 1. 4 microscope slides 2. Petroleum Jelly 3. Tongue depressors 4. 4 petri dishes 5. Glass-marking pencil 6. Microscope Procedures: Write your initials on the line after each completed step. 1. Work in groups of two or four students. Obtain four glass slides, petroleum jelly, four tongue depressors, and four petri dishes. Make four particle traps by using a tongue depressor to smear the center of four glass slides with petroleum jelly. Place each particle trap in the bottom half of a petri dish. Cover each petri dish immediately. CAUTION: Wear your safety goggles and laboratory apron. Handle all glassware carefully. __________ 2. Select one location on the school grounds for your particle traps. After obtaining your teacher’s approval, place the four petri dishes containing the particle traps in the selected location. Make sure that the petri dishes are side by side. __________ 3. Remove the lids of the petri dishes and expose the traps to the air for 20 minutes. __________ 4. At the end of the exposure time, replace the lids. Use the glass- marking pencil to record the test location on the lid of each petri dish. Return to your classroom. __________ 5. Carefully remove the particle trap from the first petri dish and place it on the stage of a microscope. Use the low-power objective to examine the slide. Count the number of trapped particles and record this number in Data Table 1. CAUTION: Do not touch or taste the particles you collect. Wear plastic gloves. Always handle the microscope with extreme care, and do not use it around water or with wet hands. Never use direct sunlight as the light source for the microscope. __________ 6. Repeat step 5 for each of the remaining particle traps. __________ 7. Calculate the average number of particles trapped at your selected location. Record this average in Data Table 1. To find the average number, add the number of particles counted on each trap and divide by 4. __________ Laboratory Planning Format Problem/Purpose *Why are you doing the How can air pollution be detected? experiment? *What question are you trying to answer? Hypothesis: How will the amount of pollution present in different samples of air compare to the amount of pollutants present in a control sample of air? Prepare an if/then statement. Independent Variables Dependent Variables Controlled Control Variables Group Describe your plan. You will investigate the amount of pollutants present in air samples from areas in which you live. What will you need to control? Data Table/ Collection Example of a data table Prepare 2 data tables. Data Table 1: Particle trap locations and number of You will need a data table particles for the following: Particle Trap Location Number of Particles 1. The location of each particle trap and the number of particles trapped for each location 2. The average number of particles trap using all particle trap locations Graph: Use the results from data table 1 to make a graph. Plot the location on the x-axis and the number of particles on the y-axis. Include the average number of particles for all traps in this graph. Use a computer to graph your data using excel. Analysis and Conclusion To Be Completed AFTER Data Collection! How did you measure air pollution in this investigation? What are some weaknesses in the way you measured air pollution? Were there any particle traps in which you did not see any particles? Can you infer that air in such a location is free of pollutants? In which location was the greatest average number of particles trapped? What factors do you think increased the average number of particles trapped in this location? In what types of weather you would expect air pollution to be the worst? Explain the basis of your prediction.
Pages to are hidden for
"Air Pollution Revised Lab"Please download to view full document