Chemisrry qnd New Mqteriqls Mony moteriols you use every doy come from noture. For instonce, the cotton in ieons comes from o plont. The wool in o sweoter is sheep's hoir. But some ordinory moteriols ore not found in noture. Scientistsinvented them. For exomple, nylon in iockets ond other clothing, plostics in toys ond mony other obiects, ond even concrete in sidewolks ond roods ore oll moteriols thot people mode.
Mqteriqls for Everydqy Use In the 1800s, scientistsbegon working to moke o fiber to use insteod of silk. Silk is strong, soft, smooth, and comfortoble to weqr. To make silk though, people hod to get threods from silkworm cocoons. Thot is one reoson silk hos been expensive. In the 1880s o French scientist mode o soft, shiny fiber that wos like silk. The only problem wos thot it eosily burst into flomes. In the mid-1930s,on Americon chemist reoched success.His silklike fobric, colled nylon, wos perfect for stockings. It soon wos used for moking ropes, nets, fishing line, ond mony fobrics. Nylon is o polymer-o lorge molecule mode of mony iden端col smoller units connected together. In nylon, eoch unit is mode of six corbon otoms, seven hydrogen otoms, ond one Thesolufionin this beokeris drown oul tro nitrogen otom. A polymer moy hove thousonds or millions mokenylonthreod. of units in o single choin. Plostic is onother type of polymer thot scientistsleorned to moke in the loborotory. One kind of plostic molecule hos o long choin of corbon otoms, eoch with two hydrogen otoms. Mony plostics ore mode with chemicols found in petroleum. Plostics ore usefuI becouse they ore lightweight ond longlosting. They ore olso foirly cheop to moke.
Mqteriqls for Building
Plosticis usednol just for moking loys.Thisortificiol heortis modeof metolondplostic.
388
You might think thot concreteis iust sond mixed with woter. But the moin ingredient is cement-o humon-mode moteriol. To moke concrete,cementis mixed with grovel, sond, ond woter. Cementsetsduring o chemicol reoction.The resulting concreteis rocklike-hord ond longJosting.
t: