### AEROSOL LAB ACTIVITY

# Introduction

Dust storms, forest fires, volcanic eruptions, and various other natural
events emit enormous quantities of minute particles into the atmosphere.
Also, human activities such as biomass burning, vehicular emissions, and
industrial processes generate huge amounts of fine particles that are
released into the atmosphere. When these particles, which may be solid
or liquid droplets, are suspended in the atmosphere, they are generally
referred to as aerosols. Aerosol particles range in size from very small
sub-visible up to raindrop sizes. Aerosols at high altitudes are often
transported over very long distances and are sometimes spread globally
by winds and circulation patterns. Typically, they remain in the
atmosphere for relatively long periods, often a year or more. Aerosols
closer to the ground have much shorter residence times in the atmosphere
as they are usually removed by sedimentation and weather processes.
Certain types of aerosols pollute the air, and in some cases pose
potential health problems. Aerosols with certain chemical and physical
properties are potentially capable of influencing chemical changes in
the atmosphere. They may also impact global climate by altering the
Earth's radiation balance. For these reasons, aerosols are a subject of
great interest and are widely studied by environmental and atmospheric
scientists.

The extent to which aerosols may affect the environment or the radiation
balance depends largely on the amount of aerosols present in the
atmosphere. The number of aerosol particles in a given volume of air
(particles per cubic centimeter) is one convenient way to quantify
aerosols. There is a variety of ingenious methods used by researchers to
measure aerosol number concentrations over various particle size ranges.
Some methods require the use of sophisticated instruments such as laser
particle counters. There are, however, much simpler techniques that may
be used for dust particles and other aerosol particles in the visible
size range. The Aerosol Lab activity is based on a very simple method
which involves collecting and counting aerosol particles. It introduces
the concept of random sampling, which may be new to many students. But
the concept is used in a way that is not difficult to understand. Only
inexpensive and easily obtainable materials are required. Many ideas for
student field projects can be derived from the basic principles
presented by the Aerosol Lab activity.

# Focus of the activity

To apply what they have learned about air-borne aerosols, students will
work in groups to make an aerosol sampler, a simple adhesive tool that
allows students to collect data and estimate the extent of aerosols
present in their school community and neighborhoods. The students will
then use the computer to send the data to SOLAR. By participating in
this activity, students will obtain a quantitative measurement of the
aerosols present in the neighborhood of the school and, as an optional
activity, at students' homes.

#### Credits

This activity is taken from *Space-Based Astronomy, A Teacher's guide
with Activities*, a NASA publication for grades 5-8; and from *The
Measurement of All things: Atmospheric Detectives*, Program 2 in the
1999-2000 NASA CONNECT Series found at the NASA CONNECT web site:
[http://connect.larc.nasa.gov/pdf/measure.detect.guides.pdf](http://edu.larc.nasa.gov/connect/detect.html)

#### National Educational Standards and Instructional Objectives

#### NATIONAL MATH STANDARDS

-   Problem Solving

-   Measurement

-   Number Sense and Numeration

-   Probability and Statistics

-   Data Analysis

##### NATIONAL SCIENCE STANDARDS

-   Science as Inquiry

-   Earth and Space Science

-   Science in Personal and Social Perspectives

-   Science and Technology

##### NATIONAL TECHNOLOGY STANDARDS

-   Basic Operations and Concepts

-   Technology Research Tools

##### INSTRUCTIONAL OBJECTIVES

Students will

-   work cooperatively in groups to collect, analyze, and interpret
    data, and make predictions.

-   measure to nearest meter.

-   quantitatively measure the aerosols present in their school and home
    communities.

-   use random, sampling to plot/determine points on a coordinate grid.

-   calculate the mean for each of the 10 random samples.

-   observe and record weather conditions.

-   record, graph, and present the results.

-   determine how weather conditions and geography affect the amount of
    aerosols in the atmosphere.

-   understand how chemical hazards (pollutants in the air) affect our
    climate.

-   demonstrate a sound understanding of the nature and operation of
    technology systems.

-   use technology to locate, collect, and evaluate information.

# Before the activity

Encourage students to research aerosols, the atmosphere, and other
related topics by using the library and the Internet, including the
SOLAR Learning Center. Ask students to share their thoughts or write
their responses to the following questions:

What is air?

What would happen to you if air did not surround the Earth?

Is the atmosphere always the same?

How do atmospheric changes affect our daily lives?

What are aerosols?

What are some examples of aerosols in the neighborhood around our
school?

Note: Due to wide variations in air quality, it is recommended that this
activity be pre-tested in the school neighborhood to learn how long to
expose the sampler. The time period may have to be extended to several
days to show measurable results.

**Materials Needed (per group at school)**

2 pieces clear contact paper (14 cm square)

2 copies of Aerosol Sampler Grid

2 pieces of cardboard or 1/4-inch plywood (30 cm square)

Cellophane tape

Magnifying glass

1 six-sided die

1 copy of Student Data Worksheet I

1 copy of Aerosol Sampler Bar Graph

**Materials Needed for Extension Activity (per student to take home)**

1 piece clear contact paper (14 cm square)

1 copy of Aerosol Sampler Grid

1 piece of cardboard or 1/4-inch plywood (30 cm square)

1 copy of Student Data Worksheet II

1 copy of Bar Graph of Data Collected from Home

+--------------------+-------------------------------------------------+
| . **.** . **.**    | ## LAB ACTIVITY                                 |
|                    |                                                 |
| **.** . . . .      | Note: This activity will require one day of     |
|                    | preparation and two days                        |
| . . . . **.** .    |                                                 |
|                    | for implementation.                             |
| . **.**            |                                                 |
|                    | 1.  **Day 1: Prepare the particulate sampler**  |
| **.** . **.**      |                                                 |
|                    | -   Locate the specific location of a flat,     |
| #                  |     elevated, open area. The surface does not   |
|  Figure 1. Sampler |     have to be horizontal. Students need to     |
|                    |     have easy access to this area.              |
| ![](media/imag     |                                                 |
| e1.png){width="0.5 | -   Divide the class into 4 research groups.    |
| 833333333333334in" |                                                 |
| height="0.77       | -   Have each group tape 1 piece of contact     |
| 08333333333334in"} |     paper in the center of the cardboard with   |
|                    |     the sticky side up. Keep the protective     |
| ***Figure 2.       |     backing on the contact paper (*see Figure   |
| Completed          |     1*).                                        |
| sampler***         |                                                 |
|                    | -   Repeat above procedures for a total of 2    |
| ***The grid has    |     aerosol samplers for each research group.   |
| been placed over   |                                                 |
| the sticky side of | 2.  **Day 2: Conduct the experiment at school   |
| the contact        |     and analyze the results**                   |
| paper.***          |                                                 |
|                    | -   Assign each research group an area on the   |
|                    |     school grounds to place its aerosol         |
|                    |     sampler.                                    |
|                    |                                                 |
|                    | -   Have each group complete the \"Morning\"    |
|                    |     column on                                   |
|                    |                                                 |
|                    | > Table A: Observations of Weather Conditions   |
|                    | > on Student Data Worksheet I .                 |
|                    |                                                 |
|                    | Note: You will need to read the local paper,    |
|                    | watch the local weather,                        |
|                    |                                                 |
|                    | or visit [http://www.weather.com]{.underline}   |
|                    | before filling in statistics.                   |
|                    |                                                 |
|                    | -   Have each group select one of its samplers  |
|                    |     for use in the predetermined morning time.  |
|                    |     Place the aerosol sampler outside on a flat |
|                    |     surface, preferably a meter or two above    |
|                    |     the ground.                                 |
|                    |                                                 |
|                    | Note: You may have to anchor the sampler if the |
|                    | air is windy. Make                              |
|                    |                                                 |
|                    | sure the contact paper is firmly taped to the   |
|                    | cardboard.                                      |
|                    |                                                 |
|                    | -   Remove the protective backing from the      |
|                    |     contact paper.                              |
|                    |                                                 |
|                    | -   Expose the sampler to the outside for at    |
|                    |     least 2 hours. Place the Aerosol Sampler    |
|                    |     Grid, grid side down, over the collecting   |
|                    |     surface and return the sampler to the       |
|                    |     classroom.                                  |
|                    |                                                 |
|                    | -   Remove the sampler from the cardboard and   |
|                    |     observe the aerosols from the back side of  |
|                    |     the clear contact paper (grid should be     |
|                    |     showing through). (*see Figure 2*.)         |
+--------------------+-------------------------------------------------+

-   Using the magnifying glass or holding the contact paper up to a
    light (i.e., an overhead projector), count the number of aerosols
    found in each of 10 randomly selected squares on the Aerosol Sampler
    Grid. Randomly select the squares by tossing one die twice. For
    example, if the numbers come up 2 and 5, the square is found in the
    second column, fifth row.

-   Record the number of aerosols in each sample square in the \"#
    aerosols (Morning)\" column of Table B: Aerosol Sampler Collection
    Data on the Student Data Worksheet I. Add up all the aerosols in the
    10 randomly selected squares to get a total. Next, divide the total
    number of aerosols counted by 10 to get an average or mean number
    per square..

-   Repeat the steps for the afternoon sample. After the average number
    of aerosols for each of the 2 samplers has been calculated,
    construct a bar graph using the Aerosol Sampler Bar Graph to compare
    the data.

-   Compare and discuss the results of the two findings. See "Analyzing
    the Data" .

EXTENSION ACTIVITY

3.  **Day 2 (continued): Conduct the experiment at home and analyze the
    results at school.**

-   Have students prepare their own aerosol samplers (*see Day 1*) to
    take home and place outside on a flat surface, preferably a meter or
    two above the ground.

Note: As in the class activity, students may have to anchor the sampler
if the air is

windy. Remind students to make sure the contact paper is firmly taped to
the

cardboard.

-   Remove the protective backing from the contact paper.

-   Students should expose the sampler overnight (approximately 8
    hours), place the Aerosol Sampler Grid, grid side down over the
    collecting surface and return the sampler to school.

4.  **Day 3: Analyze the results at school.**

-   Repeat procedure from Day 2. Record weather conditions in Table C:
    Observations of Weather Conditions from Home. Record data in Table
    D: Aerosol Sampler Data: Collection from Home. Tables C and D are
    found on Student Data Worksheet II.

-   Have students write their address and the total number of aerosols
    from Table D: Aerosol Sampler Data: Collection from Home on Student
    Data Worksheet II on a self-adhesive note.

-   Divide a map or diagram of your community or area into 4 regions:
    Northwest, Northeast, Southwest and Southeast. Have students place
    their labeled adhesive notes on the map/diagram where they live.

-   Using the data from the map, find the average for each region (NW,
    NE, SW and SE) and make a class graph of the data. See Graph of Data
    Collected from Home.

-   Compare and discuss the results of the data. See "Analyzing the
    Data" .

Note: Contact your local air pollution authority or the U. S.
Environmental Protection Agency for additional information about the air
quality in your community.

5.  **Analyzing the Data**

Students should review their observations and data and respond to these
questions in their journals or in the form of a classroom discussion:

1.  Did the weather conditions affect the results of this activity? If
    so, how?

> *(See data collected on local weather conditions.)*

2.  What types of weather conditions could cause the results to change?
    Why? *(Conditions like wind, rain, snow, or extreme heat could cause
    a change in results. These conditions affect the number of aerosols
    present in the air.)*

3.  What other factors can be identified that could affect the results
    of the activity? *(Time left outside, location of sampler and
    contaminated contact paper may affect the results of the activity.)*

4.  What caused the different amounts of aerosol matter found in the
    atmospheric samples? *(Answers vary according to population,
    industry, agriculture and geography. For example, combustion
    products from cars, fireplaces, volcanic eruptions, and a variety of
    other sources including dust from meteorites and comets, could
    contribute to the number of aerosols collected.)*

5.  What are other methods you might use to collect data on atmospheric
    particulate matter? *(Observe deposits of aerosols on objects, i.e.,
    cars, glass, furniture.)*

6.  If the EXTENSION ACTIVITY was completed, look at the map and the
    data you collected from home. What is the relationship between where
    a student lives and the number of aerosols collected*? (Answers vary
    according to population, industry, agriculture and geography. For
    example, combustion products from cars, fireplaces, volcanic
    eruption, and a variety of other sources, including meteorites and
    comets, could contribute to the amount of aerosols collected in a
    community.)*

**AEROSOL SAMPLER GRID**

**6**

**5**

**4**

**3**

**2**

**1 2 3 4 5 6**

**1**

**1 2 3 4 5 6**

**STUDENT DATA WORKSHEET I**

**Table A. Observations of Weather Conditions**

+-----------------------+----------------------+-----------------------+
|                       | **Morning**          | **Afternoon**         |
+-----------------------+----------------------+-----------------------+
| Date                  |                      |                       |
+-----------------------+----------------------+-----------------------+
| Time                  |                      |                       |
+-----------------------+----------------------+-----------------------+
| Temperature           |                      |                       |
+-----------------------+----------------------+-----------------------+
| Weather Conditions    |                      |                       |
|                       |                      |                       |
| (cloudy, rainy,       |                      |                       |
| sunny)                |                      |                       |
+-----------------------+----------------------+-----------------------+
| Relative Humidity     |                      |                       |
+-----------------------+----------------------+-----------------------+
| Wind Speed            |                      |                       |
+-----------------------+----------------------+-----------------------+
| Barometer             |                      |                       |
+-----------------------+----------------------+-----------------------+
| Dust or other visible |                      |                       |
|                       |                      |                       |
| aerosols              |                      |                       |
+-----------------------+----------------------+-----------------------+

**Table B. Aerosol Sampler Collection Data**

+-----------------------+----------------------+-----------------------+
|                       | **\# Aerosols        | **\# Aerosols         |
|                       | (Morning)**          | (Afternoon)**         |
+-----------------------+----------------------+-----------------------+
| Sample Square 1       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 2       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 3       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 4       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 5       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 6       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 7       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 8       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 9       |                      |                       |
+-----------------------+----------------------+-----------------------+
| Sample Square 10      |                      |                       |
+-----------------------+----------------------+-----------------------+
| **Total**             |                      |                       |
+-----------------------+----------------------+-----------------------+
| **AVERAGE number**    |                      |                       |
|                       |                      |                       |
| **of aerosols per     |                      |                       |
| square**              |                      |                       |
+-----------------------+----------------------+-----------------------+

**STUDENT DATA WORKSHEET II**

**Table C. Observations of Weather Conditions from Home**

Morning Afternoon

+-----------------------+-----------------------+-----------------------+
| Date                  |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Time                  |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Temperature           |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Weather Conditions    |                       |                       |
|                       |                       |                       |
| (cloudy, rainy,       |                       |                       |
| sunny)                |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Relative Humidity     |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Wind Speed            |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Barometer             |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Dust or other visible |                       |                       |
| aerosols              |                       |                       |
+-----------------------+-----------------------+-----------------------+

**Table D. Aerosol Sampler Data: Collection from Home**

  -------------------------------- --------------------------------------
                                   **\# Aerosols (Home)**

  Sample Square 1                  

  Sample Square 2                  

  Sample Square 3                  

  Sample Square 4                  

  Sample Square 5                  

  Sample Square 6                  

  Sample Square 7                  

  Sample Square 8                  

  Sample Square 9                  

  Sample Square 10                 

  **Total**                        

  **AVERAGE number of aerosols per 
  square**                         
  -------------------------------- --------------------------------------

**AEROSOL SAMPLER BAR GRAPH**

**Average**

**Number**

**of Aerosols**

**per Square**

**Sampler 1 Sampler 2**

**\"Morning\" \"Afternoon\"**

**BAR GRAPH OF DATA COLLECTED FROM HOME**

**Average**

**of Aerosols**

**per Region**

**NW NE SW SE**

**Region Region Region Region**