Day: April 17, 2010

Insulators and Conductors: Electrical and heat

• Metals conduct electricity. (Allow electricity to pass through them)
• Plastic is an electrical insulator. (Does not allow electricity to pass through)
• Some metals are magnetic (See magnetism)
• Metals are malleable, they can be molded into shape.
• As well as electrical conductors and insulators, there are thermal conductors and insulators. When we use a saucepan we don’t want to burn our hands on them so we make the handles out of materials that won’t get hot so quickly like wood or plastic.
• Thermal Insulators don’t allow heat to pass through them easily.  We want the food in the saucepan to get hot quickly so we make the saucepan out of metal, which is a good conductor of heat, it allows heat to pass through it easily.

• Thermal conductors, allow heat to pass through them quickly

Metals

Metals are classed as metals because they have certain similar properties. Other elements are classed as non-metals because they have certain other similar properties which are different from those of metals.

Metals are shiny when they are polished, where as non-metals do not shine when polished. Most metals are solid at room temperature, while non-metals can be in any of the three states of matter at room temperature. Metals are good conductors of heat and electricity, while non-metals are not. Metals can be hammered into sheets and stretched into wires, but non-metals cannot.

Some substances are classified as metal:

• Are found underground.
• Have many useful properties:

Strong, malleable, shiny, can be recycled, some are magnetic, some are good conductors of electricity, good conductors of heat.

• Some have a weakness: they corrode (rust).

Non-Metal

Only 22 of the elements are non-metals. Half of these are gases, only one (bromine) is a liquid. The rest are solids. All of these elements are found on the Periodic Table.

One of the solid non-metals is sulphur. Sulphur is found naturally in areas where there are volcanoes. Sulphur melts quite easily. Like almost all non-metals it will not conduct heat or electricity.