A Grey Area

The Educator Guide has a script, materials list, and prep directions. Be sure to have it open and ready to help guide you through every activity. 

• Post EDP Poster. 
• Cut and distribute Water Sample Recipes to groups. 
• Copy and cut Secchi disks on Educator Guide p. 27. 
• Review how to test water quality in guide. 
• Set up Materials Table: measuring spoons and scissors. 
• Optional: copy acidity chart on Educator Guide p. 29.

How can we tell if water is safe enough to reuse? 

• Investigate common household water contaminants. 
• Categorize model sample qualities as pure water, waste water, or greywater based on the contaminants found. 

Rain is slightly acidic. Most rain has a pH of 5.6 to 5.8. This occurs because carbon dioxide (CO2) from the atmosphere dissolves into rain water. Rain is likely to get more acidic as CO2 levels rise.

• Have paper towels and a sink handy for clean-up. 
• Set pH strips on paper towels. 
• Higher water quality scores = higher quality. 
• Use the Water Quality Cheat Sheet. See additional A1 card. 

Greywater: water that has been used at least once and can be used again 

Waste water: water that is too dirty to be used again