Investigate Chemical Changes - What are some signs of chemical change?
Jeanine Salisbury, Robbinsdale Middle School, Robbinsdale, MN based on an original activity from McDougal Littell Science, Matter and Energy p.47
This activity is a classroom lab activity that demonstrates chemical change in a dramatic way using a few inexpensive, easily obtainable materials.

Determining the color of nitrogen dioxide through inquiry: a demonstration of LeChatlier's principle.
Lisa Hines, Tech High School, St. Cloud, MN, based on the original activity provided by Major Dan Brannan, USAFA Department of Chemistry.
This activity is an inquiry lab where students observe the effects of temperature change on nitrogen dioxide gas, a common component of polluted air, to determine its color.