Physical properties of materials

Question 1

What are the meanings for the following : comprehensive strength, tensile strength and flexibility

Answer 1

Comprehensive - strength of an object that prevents it from crushing or changing shape when it is pushed or squeezed (concrete, rock or brick)
Tensile - strength of an object that prevents it from breaking when it is being pulled (steel)
Flexibility - the ability of an object that allows it to bend easily (rubber hoses, car tyres, plastic ruler or clothing

Question 2

what are the 3 states

Answer 2

gas, solid, liquid

Question 3

what are the meanings for the following : melt, melting point, boil, boiling point, electrical conductors and insulators and electrical conductivity

Answer 3

melt - substances changes form liquid to solid
melting point - the temperature at which a substance melts
boil - substance changes from a liquid to a solid
boiling point the temperature at which a substance boils
electrical conductors - materials that allow electricity to pass through them
electrical insulators - opposite of a electrical conductors
electrical conductivity - the ability of a material to conduct electricity

Question 4

what influences the melting and boiling of materials

Answer 4

pressure and impurities such as chemicals in water and in Johannesburg the water boils at 96 degrees because of low air pressure

Question 5

What are the melting point for the following: iron, lead, silver, gold, copper, ethanol, salt and paraffin

Answer 5

iron - 1535
lead - 327
silver - 962
gold - 1064
copper - 1085
ethanol - 78
 salt - 800
paraffin - 150-300

Question 6

what do we do to make sure we don’t get injured when handling electrical wires

Answer 6

we cover the wires in insulators like rubber or plastic

Question 7

why do we make lead fuses

Answer 7

lead has a low melting point so if the wires have an electrical fault the lead fuse will melt and no other wires will get damaged

Question 8

Meanings : heat and thermal conductivity, thermal insulators and variables

Answer 8

heat conductivity - the ability of a material to let heat flow through it
thermal conductivity - same as heat conductivity
thermal insulators - material that don’t let heat flow through them
variables - factors that can change, are observable and messurable

Question 9

name a few other factors that come into account when we choose a specific material

Answer 9

colour, style, price, appearance, comfort and texture