From Atoms to Materials

Appearance At room conditions, iron is a shiny solid when freshly cut. The density of iron is 7.87 g/cm 3 . Density Melting point Iron melts at 1538 ˚C. Thermal conductivity* Iron is a good conductor of electricity. Iron is a good conductor of heat. Electrical conductivity* Ductility* Iron can be pulled into wires. Malleability* Iron can be beaten into thin sheets. Other physical properties • taste • odour Strength Iron is very strong. It does not break easily when it is pushed or pulled. Caution DO NOT eat anything in the laboratory without the teacher’s approval. Language tip • ductility noun ; ductile adj • malleability noun ; malleable adj pull pull push pull physical property 物理性質 electrical conductivity 導電性 thermal conductivity 導熱性 ductility 延性 malleability 展性 Physical properties Physical properties are properties that may be examined without changing the composition of a substance. For example, when we measure the melting point of a substance, no new substance is formed after the measurement. So we say melting point is a physical property. Let’s take iron as an example. Some of its physical properties are: When I measure the length of a wooden stick, its composition does not change. So ‘length’ is a physical property. Iron boils at 2861 ˚C. Boiling point 7 13 From Atoms to Materials © United Prime Educational Publishing (HK) Limited 2024 All rights reserved; no part of this publication may be reproduced, photocopied, recorded or otherwise, without the prior written permission of the Publisher. Sample