Definition of chapter 4

In the chapter 4, Materials-->a substance that can be used for making or doing something Metals are a good conductor of electricity which means that they can conduct electricity due to the free moving electrons present in them. Copper is used as wiring as it is a good conductor of electricity. Metals have high melting points and high boiling points as they have strong metallic bonds. All metals are physically lustrous. They have a lustre that makes them shine. Gold is used for making jewellery. Metals are hard, they can’t be broken easily and require a lot of energy and strength to break. Iron is used to make cars, buildings, ships, etc. Metals weigh a lot as they have a high density. Metals are heavy for their size. They don’t have flexibility and have tensile strength. Metals can’t be stretched. Metals are great conductors of heat. That’s why pots, pans, vessels are made of metals.