8-3: Polymers & Composites

How do polymers form and what are composites made of?

Anticipatory Set

What do plastics have in common?

water-resistant, lightweight, flexible, comes in many colors

California StandardsScience Standard 8.3.c: Students know

atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.

Science Standard 8.6.a: Students know that carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organisms.

Inputprotein: an organic compound that is a polymer

of amino acid.amino acid: one of 20 kinds of organic

compounds that are the monomers of proteins.plastic: a synthetic polymer that can be molded

or shaped.composite: a combination of two or more

substances that creates a new material with different properties.

Input & ModelingForming Polymers

Polymers form when chemical bonds link large numbers of monomers in a repeating pattern.

Input & ModelingPolymers and Composites

Plants, animals, and other living things produce many natural materials made of large polymer molecules.

Cellulose is a flexible but strong natural polymer found in the cell walls of fruits and vegetables.

Proteins are polymers formed from smaller molecules called amino acids.

Input & ModelingPolymers and Composites

The properties of synthetic polymers make them ideal starting materials for many common objects.

The starting materials for many synthetic polymers come from coal or oil.

Plastics are the most common synthetic polymers.

Input & ModelingPolymers and Composites

Many composites include one or more polymers.

A composite combines two or more substances in a new material with different properties.

Wood is a natural composite made of cellulose and lignin. The two polymers are weak by themselves, but they are strong when combined together.

Input & ModelingRecycling Plastics

You can help reduce the amount of plastic waste by recycling.

Plastics do not react very easily with other substances, so they do not degrade into simpler materials in the environment.

Answer #1-4Guided Practice

Independent PracticeFinish the worksheet.

HOMEWORK CONNECTION Complete the Section 8-3 Review & Reinforce

Write a detailed SUMMARY of the section and complete the UNANSWERED QUESTIONS section of your notes.

Choose two of the remaining Depth & Complexity ICONS in your notes and explain how they relate to this section.