Diamonds vs. Spider Silk

Crystals and Polymers

Do you remember which molecules represent a solid?

• The molecules of most solids form regular shapes through repeating patterns.

Two Types of Solids

Crystals

(Diamonds)

Polymers

(Spider web silk)

Crystalline Solids

1. Crystals (crystalline solids) have molecules that form a regular, repeating pattern.

2. These patterns create crystals.3. In general, crystalline solids do

not get soft when heated.4. Examples of crystalline solids

are sugar, salt, and diamonds.

The Molecules in Crystalline Solids

Diamonds Graphite (pencil lead)

1.What do the round structures represent?

2.Why are all the atoms the same color?

3.Which substance is more hard? Why?

Diamond vs. GraphiteWhat is similar about these substances?

Both diamonds and graphite are made of the same atoms, carbon; despite having distinct physical properties.

•What accounts for their different physical properties (hardness, luster, density, etc)?

Two Models of Salt Molecules

1.What kind of observations can you make about the molecular structure of salt?

There are 2 different types of atoms arranged in repeating patterns that can’t change position.

Polymers

1.A polymer is a large, repetitive, string-like molecule.

2.Most organic structures are polymers made of Carbon, Hydrogen, Oxygen, and/or Nitrogen.

The Molecules in Polymers

Cotton

Silk

What are some characteristics of these structures?

Cotton and Silk

1.What are some similarities between cotton and silk?

2.Where do all polymers come from?

Polymers come from organic (living or once-living) things like plants, petroleum, and animals.