Definition: A synthetic, solid, hydrocarbon-based polymer, whether thermoplastic or thermosetting.

Alright class, settle down, let’s take a peek, At ‘plastics,’ a word that’s often sleek! The dictionary gives us quite the clue, Let's break it down for me and you. "Synthetic, solid, hydrocarbon-based polymer..." That’s a mouthful, don’t feel like a tremor! Let’s unpack it slow, with careful grace, To understand this material’s place. “Synthetic” means “made by man,” you see, Not naturally grown from tree or sea. Scientists created them, a clever design, A brand new substance, truly divine! "Solid" – it doesn't flow like water free, It holds its shape for all the world to see. Unlike liquids, it’s firm and strong, Where you belong, it won’t go wrong! “Hydrocarbon-based” - Now this is key, These plastics are built from carbon, you agree? Carbon atoms linked in a chain so neat, A hydrocarbon structure, can't be beat! And finally, "polymer..." – a big word to say, It means many smaller parts that play. These tiny pieces link together tight, Creating plastics, shining bright! Then we have “thermoplastic” or “thermosetting,” Two different types, don't you forget! Thermoplastics can soften and reshape, Like plastic bottles that you drape. Thermosets are set in place with heat, They harden firmly, a solid treat! Think of Bakelite, strong and true, A thermoset plastic, for me and you! So there you have it, class, a lesson clear, On what ‘plastics’ mean, year after year. Any questions bubbling up within? Now let's move on to how they are made...