Terms

Question 1

Material supply forms

Answer 1

• sheet -extrusions -hot and cold rolled
• plate -castings
• bar -wrought
• wire -forgings
• section -pipe and tube

Question 2

Thermal expansion

Answer 2

Metal expands when heated. Length, surface area and volume will increase with temperature. The scientific term for this is thermal expansion. The degree of thermal expansion varies with different types of metal. Thermal expansion occurs because heat increases the vibrations of the atoms in the metal. Accounting for thermal expansion is essential when designing metallic structures. An everyday example would be the design of household pipes, which must accommodate expansion and contraction as the seasons change.

Question 3

Selecting Materials

Answer 3

Materials are selected due to their properties, this is because different properties make materials suitable for different applications. When selecting materials its important to consider the following:

Heat resistance 			           
Load bearing capacity
Thermal and electrical conductivity		
Shear strength
Thermal and electrical insulation 		
Weight
Wear resistance				
Cost
Corrosion resistance

Question 4

Electron Flow

Answer 4

Electron flow is what we think of as electrical current… Each atom has electrons in it. If you put new electrons in a conductor, they will join atoms, and each atom will spit out an electron to the next atom. This next atom takes in the electron and spits out another one on the other side.

Question 5

Structure of an Atom

Answer 5

The definition of atomic structure is the positively charged nucleus and the negatively charged electrons circling around it, within an atom. An example of atomic structure is what gives energy to atoms and then to molecules.

Question 6

Charged particles

Answer 6

In physics, a charged particle is a particle with an electric charge. It may be an ion, such as a molecule or atom with a surplus or deficit of electrons relative to protons. It can also be an electron or a proton, or another elementary particle, which are all believed to have the same charge.

Question 7

Coulomb

Answer 7

A coulomb is a unit of electrical charge. Charge is given the symbol Q. Electrons are tiny and have a very small charge. In the physics of electricity, we take a very large number of electrons as 1 unit of charge called a coulomb.

Question 8

Ampere

Answer 8

An ampere is a unit of measure of the rate of electron flow or current in an electrical conductor. One ampere of current represents one coulomb of electrical charge.