• 6-8: 4D/M1a. All matter is made up of atoms, which are far too small to see directly through a microscope.
• 6-8: 4D/M1cd. Atoms may link together in well-defined molecules, or may be packed together in crystal patterns. Different arrangements of atoms into groups compose all substances and determine the characteristic properties of substances.
• 6-8: 4D/M6a. There are groups of elements that have similar properties, including highly reactive metals, less-reactive metals, highly reactive nonmetals (such as chlorine, fluorine, and oxygen), and some almost completely nonreactive gases (such as helium and neon).
• 9-12: 4D/H7a. Atoms often join with one another in various combinations in distinct molecules or in repeating three-dimensional crystal patterns.

• 9-12: 8B/H4. Increased knowledge of the properties of particular molecular structures helps in the design and synthesis of new materials for special purposes.

• 6-8: 11B/M1. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly. They are also used for processes that are too vast, too complex, or too dangerous to study.

This interactive activity from NOVA describes the crystalline structure of metal and uses animations to illustrate the molecular changes that occur when a metallic substance is bent, heated, or otherwise changed by external forces. It also explores the three main types of bonds that bind atoms together: metallic, ionic, and covalent.

• Physical Sciences K-8 Properties of Matter Unit
• Physics First Properties of Matter Unit
• Conceptual Physics Properties of Matter Unit
• Algebra-Based Physics Properties of Matter Unit