Polymers: Linking things together!

Polymers: Linking things together!

Today students had a fun chemistry lesson on polymers. The students learned how important polymers are in their lives, since polymers include starches (pasta, potatoes), cellulose (wood, plants), plastics, fabrics both natural (cotton, wool) and manufactured (rayon, nylon), and proteins. But exactly what is a polymer, you might ask? Polymers are a type of molecule made of linked chains of individual units, called monomers. Students learned that monomers form chains to create polymers, and that chains of polymers can be cross-linked together to make materials with different properties, like density, tensile strength, and elasticity.

After learning about the polymers that are all around us, students were then able to experiment with some cross-linking polymers themselves. We took an existing polymer (white school glue, which is polyvinyl acetate) and mixed it with a cross-link solution, tetrahydroxyborate (Borax) in water. The result was dramatic! The slimy, sticky glue changed into a rubbery, dry substance that could be stretched, formed into a ball, broken sharply apart, and bounced. Your students should be able to tell you why cross-linking the polymer had this effect!


Polímeros: ¡entrelazando cosas!

Hoy los estudiantes tuvieron una clase de química muy entretenida sobre  polímeros y aprendieron la importancia de éstos en nuestra vida. El almidón (papas, pasta), la celulosa (madera, plantas), el plástico, las telas tanto naturales (algodón, lana) como manufacturadas (rayón y nylon) y las proteínas, son todos ejemplos de polímeros. Pero, ¿qué es un polímero? Los polímeros son un tipo de moléculas compuestas por cadenas de unidades individuales llamadas “monómeros”. En esta clase, los alumnos aprendieron que los monómeros forman cadenas para crear polímeros, los cuales a su vez, pueden unirse entre sí para crear materiales que poseen diferentes características, como densidad, resistencia y elasticidad.

Después que los estudiantes comprendieron que estamos rodeados por polímeros, tuvieron la oportunidad de experimentar con polímeros que ellos mismos crearon.

Para la actividad, tomamos un polímero ya existente (pegamento o cola fría blanca o también conocido como acetato de polivinilo) y lo mezclamos con una solución de “entrecruzamiento” (cross-linking), llamada tetrahidroxiborato (Bórax) en agua.

¡El resultado fue impresionante! El pegamento que antes era pegajoso se transformó en una sustancia seca y como de goma, la cual podía ser estirada, podía moldearse en una pelota, se podía romper y además rebotaba. Sus hijos o hijas deberían ser capaces de explicarles por qué ocurrió este fenómeno al añadir la solución de entrecruzamiento.

Clases más avanzadas:

A continuación, probamos el efecto que tienen diferentes cantidades de polímeros sobre la elasticidad del polímero gel. Para ésto, medimos la altura de rebote de la pelota de gel. Pregúntele a sus hijos o hijas por qué una de las pelotas de gel rebotó más alto que la otra.


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Lauren Koppel

Lauren earned a Bachelor’s degree with a double major of Biology and Psychology from Clark University, and a Master of Education from the Harvard Graduate School of Education. During her undergraduate years, she worked in a evolutionary neurobiology lab that studied the neural development of annelids (marine worms), with a focus on the sox family of genes. Lauren loves learning about how the world works (including everything from biology to chemistry to engineering), and is passionate about sharing that knowledge and enthusiasm with others. In the past, she has interned at the Museum of Science, where she educated learners of all ages through hands-on activities, games, and experiments. Other science education organizations with which Lauren has worked include The People’s Science, EurekaFest, and Eureka! of Girls Inc. of Worcester. Currently she lives in Boston, where devotes her free time to playing Quidditch, reading sci-fi novels, playing her ukulele, and enjoying all the culinary delights the city has to offer.

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