What does parts per million mean?
How different is 1 part per million from 1 part per billion?
Relatively speaking, how much nitrogen, oxygen, and argon are in the atmosphere?
TIME NEEDED: 45 minutes - 1 hour
OPTION 1: Food Coloring
Food coloring White ice cube tray
eyedroppers or pipettes
Several cups of water
Coffee filter or paintbrush
OPTION 2: Milk
Ten 100-ml beakers 100 ml of milk
Graduated pipette (optional)
Small focused light beam
Labels for beakers
TOPICS: parts per million, parts per billion, ratios, percentages
TYPE: hands-on demonstration, math calculations
ESSENTIAL STANDARDS for Earth/Environmental Science:
EEn.2.5.1. Summarize the structure and composition of our atmosphere
EEn.2.5.5 Explain how human activities affect air quality
Parts Per Million
In the hands-on activity, students will develop an understanding of the terms parts per million (ppm) and parts per billion (ppb) by systematically diluting a solution of food coloring and water. They will convert ratios to percentages to ppm to ppb. They will correlate the ratios they’ve created in the classroom to the ratios of various gases in our atmosphere. As another option, the class can do a similar activity using milk and water. In this case, students can demonstrate the Tyndall Effect in which a beam of light is visible in a mixture of water and milk, even when mixture appears clear to the naked eye.
Parts Per Million - Teacher to Teacher Tips
The quick video below has tips for doing this activity from Mark Townley, an award-winning, North Carolina high school teacher. Mark helped develop It’s Our Air and has used each of these activities with his students.
OTHER MODULE 1 (AIR POLLUTANTS & THEIR SOURCES) ACTIVITIES AND VIDEOS
1-3 Parts Per Million (this activity)