Young scholars examine how micro-organisms are living organisms that are often too small to be seen. They explain that micro-organisms may be beneficial or harmful.

Students will learn about reversible and irreversible changes in materials in this lesson.

Join Leander in his chemistry lesson, and learn about the change of different types of substances.

With an overview of topics related to chemical energetics, this site provides a foundation to a study of thermodynamics and its relation to entropy. Information on the topic ranges from reversible and irreversible changes to standard...

[Free Registration/Login Required] This unit brings together and consolidates work that children have done before on reversible changes and introduces irreversible changes. Students are guided through experiments illustrating the...

[Free Registration/Login may be required to access all resource tools.] Covers reversible and irreversible physical changes.

Help solve the mystery and find the missing crystal. Following the activity, read more about chemical and physical changes, and then take a quick quiz to check for understanding.

[Free Registration/Login may be required to access all resource tools.] Covers reversible and nonreversible changes.

Learn about topics related to the material world. Each topic includes facts, a glossary, an interactive quiz, printable worksheets, an image bank, and web links.