A plastic bag, a nylon rope, a rubber band and the DNA in every cell are made of the same kind of thing: molecules thousands of times longer than they are wide. Grown on the page and then measured: how chains are made one step or one monomer at a time; how long they get and how wide their distribution is; how a chain coils like a random walk and why polymers dissolve slowly and mix badly; how chains pack into crystals or freeze into glass, why a rubber band snaps back and warms when stretched, why plastics creep, crack and flow; how pellets become bottles, films and fibres; and what happens to plastic after use. Set the conversion, the initiator, the temperature or the stretch and watch the result — every distribution, curve and estimate computed by the page.
Every chain, curve and number on these pages is computed by the page or cited with its source; your progress stays in this browser. Chemistry is explained, never given as a procedure: no plate tells you how to make a polymer from reactive chemicals, and the few home experiments use only household materials. Figures on additives, microplastics and the environment are cited with their dates and uncertainty, and nothing here is health, product, regulatory or engineering advice. The course endorses no product or company: trade names appear only where they are part of the history of the subject. Not affiliated with or endorsed by any organisation, university, publisher or author mentioned here.