Computer

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Earth Science with Vernier P5 - 1

Measuring Particulates Air pollution affects everyone. It comes in various forms including emitted gases, ozone, and particulate matter. Short-term exposure to air pollution can result in throat and eye irritation as well as difficulty breathing. Prolonged exposure to particulate pollution can result in chronic health concerns, such as cancer and damage to the body's immune, neurological, reproductive, and respiratory systems. Those most susceptible include the elderly, children, and people with asthma. There are now guidelines in place to alert people to days during which the air pollution levels may be high.

Particulate matter consists of a mixture of particles ranging from large particles such as smoke, dust, and pollen to smaller ones from vehicle exhaust and coal-fired plants. The major contributors of particles to the air you breathe include coal and oil burning power plants, diesel fuel, and wood-burning fireplaces. Natural sources of particulate matter include volcanic ash, pollen and dust. The amount of particulate matter in the air can be measured using various techniques. One technique uses a device that collects particulates on a filter strip and periodically shines light through the strip to record the difference in light transmittance. This difference correlates to the particle mass collected over a period of time. You will use a similar technique.

In this experiment, you will measure the amount of light that passes through a test card that has been allowed to collect particulate matter in the air for a week. You will compare the transmittance of light through the test card to a control card.

OBJECTIVES In this experiment, you will

• Collect particulate matter from the air. • Use a Light Sensor to determine the amount of light blocked by the particulate matter. • Calculate the percent light transmittance for various locations.

MATERIALS computer string Vernier LabPro 2 ring stands Logger Pro lamp with 100W bulb Light Sensor scissors 4 × 6 inch index card utility clamp clear packing tape coin box or other airtight container

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Computer P5

P5 - 2 Earth Science with Vernier

PRE-LAB PROCEDURE 1. Prepare your test cards.

a. Obtain one 4 × 6 inch index cards for each location to be tested and one control card.

b. Using the coin as your guide, draw four circles on each test card in the locations shown in Figure 1.

c. Label the circles A–D. d. Use scissors to cut out the circles. e. Cover the holes with one large piece of

clear packing tape. Tape it so that the sticky side of the tape shows through the side of the card with the labels.

f. Punch a single hole in the top of the card and thread a piece of string 20 cm long through the hole. Tie a knot at the end of the string. This is used to hang the test cards.

2. Label each card with today’s date and the location in which it will be hung. Hang the cards in

locations that will not be disturbed by others. Place the control card in an airtight container. Leave the cards in place for one week.

PROCEDURE 1. Retrieve your test cards from their collection locations. Be careful not to touch the sticky side

of the tape.

2. If the Light Sensor has a switch, set it to 0–6000 lux. Connect the Light Sensor to LabPro.

3. Start Logger Pro and open the file “P5 Particulates” from the Earth Science with Vernier folder.

4. Prepare for data collection. a. Clamp the lamp with the bulb inserted to

one ring stand using a utility clamp. b. Clamp the Light Sensor to the other ring

stand using the second utility clamp. c. Position the clamps so that the Light

Sensor is the same height as the center of the bulb.

d. Point the Light Sensor directly at the bulb e. Move the ring stands so that the Light

Sensor is approximately 15 cm from the center of the bulb.

5. Turn on the lamp.

6. Hold the control test card in front of the Light Sensor so that sample circle A is directly in front of the sensor as shown in Figure 2.

Figure 1

Figure 2

Measuring Particulates

Earth Science with Vernier P5 - 3

7. Click to begin data collection.

8. When data collection is complete click the Statistics button, . The mean, or average, value for the data is listed in the Statistics box on the graph. Record this value in the data table.

9. Repeat Steps 7–8 for the remaining sample circles.

10. Repeat Steps 7–9 for the remaining locations.

DATA

Test Card Control Location 1 Location 2 Location 3

Location Name

Illumination Test Circle A (lux)

Illumination Test Circle B (lux)

Illumination Test Circle C (lux)

Illumination Test Circle D (lux)

Average (lux)

Percent light transmittance 100%

PROCESSING THE DATA 1. Calculate the average illumination for each test card location.

2. Calculate the percent light transmittance using the equation

% Light Transmittance = average illumination

average illumination for control × 100%

3. Which location had the lowest light transmittance? What factors contributed to this low reading?

4. What actions can you take to cut down on the number of particulates in the air?

Computer P5

P5 - 4 Earth Science with Vernier

EXTENSIONS 1. Research particulate matter guidelines for your area.

2. Position test cards in locations throughout your community.

3. Collect samples of particulate pollution in the exhaust fumes of various cars.

4. Collaborate with other schools in your vicinity to develop a particulate matter map.

Vernier Lab Safety Instructions Disclaimer

THIS IS AN EVALUATION COPY OF THE VERNIER STUDENT LAB. This copy does not include:

Safety information Essential instructor background information Directions for preparing solutions Important tips for successfully doing these labs

The complete Earth Science with Vernier lab manual includes 33 labs, 6 projects, and essential teacher information. The full lab book is available for purchase at: http://www.vernier.com/cmat/esv.html

Vernier Software & Technology

13979 S.W. Millikan Way • Beaverton, OR 97005-2886 Toll Free (888) 837-6437 • (503) 277-2299 • FAX (503) 277-2440

info@vernier.com • www.vernier.com