Lesson: What's Hiding in the Air?

Quick Look

Grade Level: 6 (4-6)

Time Required: 1 hour

Plus 1-4 weeks of daily (5 minute) data collection.

Lesson Dependency: None

Subject Areas: Chemistry, Earth and Space, Physical Science, Science and Technology

A girl blowing a dandelion in the grass.
What is hiding in the air?
Copyright © Pixabay https://pixabay.com/en/dandelions-woman-blowing-wind-609253/


Students develop an understanding of the effects of invisible air pollutants with a rubber band and hanger air test and a bean plant experiment. They also learn about methods of reducing invisible air pollutants.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Engineering Connection

Since we all realize how invisible air pollutants make the air dangerous for people to breathe, some engineers make it their specialty to design vehicles, machines and manufacturing plants that emit the fewest pollutants as possible. In the US, the EPA sets emissions standards that businesses must meet to operate and engineers must follow as guidelines. An excess of pollutants can cause acid rain, a lowering of the pH of rainwater, which upsets a balanced environment and destroys agriculture and healthy vegetation.

Learning Objectives

After this activity, students should be able to:

  • Identify the major types of invisible air pollutants and how they affect our health.
  • Conduct a simple invisible air pollutant test.
  • Explain how pollutants from the air can affect water and plant growth.
  • Describe how engineers address invisible air pollution.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

  • Make observations and measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon. (Grade 5) More Details

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  • Ask questions that can be investigated within the scope of the classroom, outdoor environment, and museums and other public facilities with available resources and, when appropriate, frame a hypothesis based on observations and scientific principles. (Grades 6 - 8) More Details

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  • Identify evidence that suggests there is a fundamental building block of matter (Grade 6) More Details

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It is a challenge for engineers to identify invisible air pollutants. Since they cannot see these pollutants, engineers often must base their initial information about possible pollutants on how the outdoor environment is being affected. From what they learn, engineers either develop materials resistant to the negative effects of air pollution or determine measures to reduce air pollution and improve the quality of life for the people living in that area.

Engineers study invisible air pollutants found indoors, too. Gas stoves, cigarette smoke and even breathing can emit pollutants. Many everyday items purchased in stores, especially those made of plastic, are produced in factories using chemicals and glues. Often, we can smell these pollutants, but we cannot see them. Over time, chemical pollutants are released inside homes and offices in a process called offgassing. Engineers study the presence of these pollutants in buildings and sometimes add fans (for increased ventilation) or take other actions, to remove them from the enclosed buildings, so people do not get sick from the indoor air.


Pre-Activity Assessment

Brainstorming: Have the students engage in open discussion to think of locations around the school at which invisible pollutants may be found. Remind students that no idea or suggestion is "silly." All ideas should be respectfully heard.

Prediction: Have students predict the outcome of the activity before the activity is performed.

  • In the Rubber Band Air Test Activity, have students predict which collection sites might have the most pollutants.
  • In the Acid Rain Activity, have students predict how they think the plants will be affected by the different solutions.

Activity Embedded Assessment

Journals: Have students be complete in recording their procedures, predictions, observations and conclusions in their journals.

Post-Activity Assessment

Informing Others / Map Making: Make a school map on large chart paper. For each collection site, cut a hanger shape from colored construction paper and write on it the ranking and location. Adhere each cut-out hanger to the correct location on the map. What conclusions can you draw from the map? Write a few of these conclusions neatly on index cards. Display the map and index cards in a school hallway for others to see. (You can also just add hangers indicating invisible pollutants to the school map made in Air Pollution unit, Lesson 2, if desired.)

Discussion Questions: Solicit, integrate and summarize student responses on the board. Ask the students:

  • What have you learned about invisible air pollution from this activity?
  • What are some signs that invisible air pollution may be present in a certain area?

Lesson Extension Activities

Test the reaction of different plant types. Are some plants more tolerant of the "polluted" water?

Determine the tolerance range for the plants by experimenting with a variety of vinegar and water concentrations.

Have students make a bar graph showing the life span of the plants (vertical) vs. the pH of the solution (horizontal). What conclusions can you draw from the graph? Can you estimate what pH range the plant can tolerate?

Offgassing is the release of chemicals from non-metallic substances. Have students research to find out as many as possible ordinary everyday products and materials that are known to be offgassing, and thus possibly contributing to poor air quality. For example, cabinets made from particle board or plywood, paints, plastics, new carpets and swimming pools.

Have students research and report to the class on "sick building syndrome." What are the indicators of a "sick building" and what might be the causes? What are possible solutions? Start with information provided by the U.S. Environmental Protection Agency, Indoor Air Facts No. 4 (revised): Sick Building Syndrome (SBS) at: http://www.epa.gov/iaq/pdfs/sick_building_factsheet.pdf.


Jones, Maclyn. Air Pollution: Visible and Invisible. Updated August 2, 2004. Lesson Plans for Teachers, TCEQ, Texas Natural Resource Conservation Commission. Accessed September 18, 2006. http://www.tceq.state.tx.us/assets/public/assistance/education/air/visible_invisible.pdf

Paxton, Kim. The Rubber Band Air Test. Updated July 28, 2004. Lesson Plans for Teachers, TCEQ, Texas Natural Resource Conservation Commission. Accessed September 18, 2006. http://www.tceq.state.tx.us/assets/public/assistance/education/air/visible_invisible.pdf


© 2004 by Regents of the University of Colorado.


Amy Kolenbrander; Sharon Perez; Janet Yowell; Natalie Mach; Malinda Schaefer Zarske; Denise Carlson

Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder


The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: January 9, 2020


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