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a)
Al vier is goeie geleiers, maar koper is byvoorbeeld ‘n beter geleier as yster. Stel posisies vas deur eksperiment te doen. Probeer om laboratoriumstafies wat ewe groot is te gebruik.
(b) ‘n Donskombers hou ‘n mens warm aangesien die liggaamshitte swak daardeur gelei word. Daar is lug tussen die donse wat ook ‘n swak geleier van hitte is. Bakstene het ook gaatjies in wat met lug gevul is wat ‘n baksteen ‘n swakker geleier maak as bv. koper wat meer solied/kompak is.
(c)
(i) Klei.
(ii) Gelei hitte van buite swak, dus sal dit binne koeler bly as buite.
(iii) Wol is ‘n swak geleier en hou die liggaamshitte dus binne.
(iv) Die leerder behoort ‘n goeie geleier te kies vir veral die boom van die pot om die hitte vinnig by die inhoud van die pot te kry om die gaarmaakproses te bespoedig. ‘n Swak geleier behoort sy keuse vir handvatsels te wees, sodat ‘n mens die pot kan hanteer sonder ‘n oondhandskoen of lap.
(v) Water is ‘n swak geleier.
(vi) Blikke is gemaak van aluminium wat ‘n beter geleier as glas is.
(a) Toets die volgende metale in ‘n vlam of kokende water. Laat elke lid van die groep ‘n metaal vashou. Rapporteer sodra die hitte jou hand bereik. Rangskik die metale sodat dié wat eerste warm word, eerste geplaas word.
| Metaal | Posisie |
| Yster | ______________________ |
| Koper | ______________________ |
| Aluminium | ______________________ |
| Lood | ______________________ |
(b) Hoekom is sekere stowwe beter geleiers as ander?
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(c) Gebruik nou jou kennis van geleiding om die volgende vrae te beantwoord.
(i) Van watter materiaal sal jy ‘n hut bou as jy wil hê dat dit koel moet wees in die somer: klei of sinkplate?
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(ii) Hoekom het jy dit gekies as boumateriaal?
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(iii) Het jy al gedink waarom ons in die winter wolklere dra? Probeer verklaar waarom wintermateriale wol bevat.
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(iv) Jy kry die geleentheid om ‘n pot te maak waarin mense kan kos kook. Watter materiale sal jy gebruik en hoekom? (Onthou, ‘n pot moet ook handvatsels hê!)
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(v) Hoekom sit ons ‘n bottel koeldrank in koue water om dit koel te hou?
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(vi) Probeer ook verklaar waarom ‘n bottel koeldrank langer sal koel bly as ‘n blikkie koeldrank.
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Leeruitkomste 2: Die leerder ken, interpreteer en pas wetenskaplike, tegnologiese en omgewingskennis toe.
Assesseringstandaard 2.2: Dit is duidelik wanneer die leerder inligting kategoriseer: vergelyk kenmerke van verskillende kategorieë voorwerpe, organismes en gebeurtenisse.
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