Effects of Aerosols in the Earth's Atmosphere
Carroll Ellis, Science Educator, MathScience Innovation Center
Questions
In this activity, you will measure the effect of excess carbon dioxide on the
temperature of gas inside of soda bottles and see what the effects of aerosols are
on the heating of the gas. What are aerosols and how could they possibly affect
the global climate? What are some of the sources of stratospheric aerosols
entering the atmosphere?
Virginia
Standards
of Learning
2010 Earth Science (ES.1, ES.13); 2010 Physical Science (PS. 2, PS.7)
21st
Century
Curriculum
Nanotechnology: Size-Dependent Properties—The properties of matter
can change with scale. During the transition from bulk material to the
nanoscale, a material often exhibits unexpected properties that lead to
new functionality.
Materials
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Two or more 2-liter clear soda bottles with the label removed.
Identical thermometers for each soda bottle or Vernier LabQuest® Data
Logger & 2 Temperature Probes.
Opaque tape.
Source of carbon dioxide (CO2).
Spray glitter.
Modeling clay.
Safety
Use caution goggles when using Alka-Seltzer® and baking powder in water.
Directions
For your source of carbon dioxide, you may use one of the following methods:
1.
Dry CO2 Source - Seltzer Bottle Charges
Fill a dry seltzer bottle with one charge of carbon dioxide. You will use the
carbon dioxide in the seltzer bottle to fill one of the bottles with carbon
dioxide. For this method, both bottles can be left dry.
The Effects of Aerosols
http://MathInScience.info
© MathScience Innovation Center/NASA, 2011
2.
Wet CO2 Source - Alka-Seltzer
You will put a cup of water into both bottles, then put a couple of AlkaSeltzers into the water in one of the bottles. A tablespoon of baking powder
can be substituted for the Alka-Seltzer.
3.
Wet CO2 Source - Alka-Seltzer
You will put a cup of water into both bottles, then put two Alka-Seltzers
into the water in one of the bottles. A tablespoon of baking powder can be
substituted for the Alka-Seltzer.
4.
Wet CO2 Source
Put a cup of club soda or seltzer water in one of the bottles and a cup of tap
water into the other bottle.
5.
The caps of the bottles will have holes drilled to the same diameter as your
thermometer. Place the thermometers through the holes in the caps several
inches. Use the modeling clay to hold the thermometers in place and seal
the hole.
6.
Insert the Vernier temperature probe through the holes in the caps and use
the modeling clay to seal the hole.
7.
Use the seltzer bottle to fill one of the bottles with CO2, or for the wet CO2
source (method 2), fill the bottles with identical quantities of water and
place the Alka-Seltzer into one of the bottles, or (method 3) place identical
quantities of seltzer/club soda into one of the bottles and plain tap water into
the other. Make sure the liquids are at the same temperature when starting
the experiment.
8.
Place the caps with thermometers onto the tops of the bottles.
9.
Put the bottles into sunshine. Make sure they receive the same amount of
sun. NOTE: A heat lamp may be substituted for the sun, but you must be
very careful to place the bottles exactly the same distance from the lamp.
10. Shade the thermometers or temperature probes by putting a strip of opaque
tape on the outside of the bottles. The tape must be the same length on both
bottles.
11. Measure the temperature of the bottles over time. Record the temperature of
each bottle every five minutes for a half hour.
12. You now add aerosols to your experiment by using two bottles with spray
glitter on the outside of the bottle.
13. Repeat steps 1-7.
The Effects of Aerosols
http://MathInScience.info
© MathScience Innovation Center/NASA, 2011
Time
Bottle #1
(air)
Temperature C0
Bottle #2
(CO2)
Temperature C0
Bottle #3
Aerosols (air)
Temperature C0
Bottle #4
Aerosols (CO2)
Temperature C0
5 min
10 min
15 min
20 min
25 min
30 min
The Effects of Aerosols
http://MathInScience.info
© MathScience Innovation Center/NASA, 2011
Additional Background Information:
Aerosols are tiny liquid and solid particles suspended in the atmosphere. These particles play a
critical role in the climate system and are present nearly everywhere, from the upper reaches of
the atmosphere to the surface air that humans breathe. They range in size from .01 microns,
about the size of the smallest bacteria, to several tens of micrometers, the diameter of human
hair.
Most aerosols tend to cool Earth’s surface. Overall, scientists estimate that aerosols have a net
cooling impact about half the strength of the warming caused by the build-up of greenhouse
gases. But, the particles are distributed very differently than greenhouse gases, primarily because
the average lifetime of an aerosol particle in the atmosphere is much shorter than that of most
greenhouse gases.
To predict the impact of climate change on human society, it is critical that scientists know
precisely how much warming and cooling aerosols produce in each of Earth's regions. For this,
comprehensive knowledge of certain aerosol properties—their size, shape and chemical
composition—is needed. However, existing satellite instruments provide only partial information
about such aerosol properties. As a result, the impact of aerosols on climate remains much less
certain in comparison to that of greenhouse gases.
Scientists use ground-based sensors and airborne field campaigns to fill in important details
about common aerosols. Such research shows that the bulk of aerosols—about 90 percent—have
natural origins. Volcanoes inject huge columns of gases high into the atmosphere that can
become sulfate particles, and sandstorms in desert regions whip small pieces of mineral dust into
the air. Fires send partially burned black carbon and other smoke particles aloft. The spray from
surface waves injects sea salt particles into marine air, and even certain plants produce gases that
react with other substances in the atmosphere to produce aerosols.
The other 10 percent of aerosols are manmade, or anthropogenic. Fossil fuel combustion
produces large amounts of sulfates. Biomass burning, a common method of clearing land, yields
smoke comprised mainly of organic matter and black carbon. Diesel engines are another
especially prolific producer of black carbon. Deforestation, overgrazing, drought, and excessive
irrigation change the soil, often leading to higher rates of dust entering the atmosphere.
Aerosol emissions are in flux around the world as economies develop and land use changes.
Although sulfate aerosol emissions have declined during recent decades in North America and
Europe because of clean air regulations, particle emissions are increasing in many other regions
of the world. Biomass burning is a major source of aerosols in South America and Africa.
Emissions of black carbon are increasing rapidly in parts of Asia.
The Effects of Aerosols
http://MathInScience.info
© MathScience Innovation Center/NASA, 2011