7 B 20 Modeling Polymers Background Plastics have

7 B 20: Modeling Polymers

Background • Plastics have different properties, but they all belong to a group of materials called Polymers. • Mono = prefix that means “one” in Greek. • Poly = prefix that means “many” in Greek. • Polymers = compounds made of thousands of repeating smaller molecules. • Monomer = molecule that repeats in a polymer • So Polymers are made of many Monomers.

Challenge Questions Give 3 examples of how models are used to show something.

Models • Scientists use models to help explain things. • Models do not have to look like the real thing. • Models do have to act like it in one or more important ways. • Some people make models from legos, popsicle sticks, or styrofoam. • Monomers can be modeled with paper clips.

Monomers • Unconnected paper clips represent Monomers • Draw some unconnected paper clips. • If you put them into a bottle and try to pour them out, how quickly do they pour out? • How easy is it to pull out just one?

Polymers • Now link and draw 6 paper clips together to form Polymers. Each clip is a Monomer. How easy would it be to pour these out of a bottle? • Link all clips together to form a 24 -link chain. Is that easy to pour out of a bottle? • Can you pull out just one single paper clip?

Cross-Linked Polymers • Separate the long chain back into 6 -link polymers and put them into parallel rows. Connect the rows with more paper clips. Draw this. This is called a Cross-Linked Polymer. • How easy would it be to pour out of a bottle?

7 B 20 Polymer Model Analysis Write questions + 1 paragraph each • 4. The models act a lot like the molecules. Based on what you observed, how does crosslinking affect the properties of a polymer? • 5. All plastics are polymers. What advantages do you think polymers have over monomers?