Unit 305 Session 5 PT5 (Hardness & Conductivity)

​Hardness of materials

Poll

Which of these do you think is the hardest material

• Diamond

• Steel

• Rock

• Bone

​Hardness is the property of a material that enables it to resist bending, scratching, abrasion or cutting.

Hardness of minerals can be assessed by reference to the Mohs scale, which ranks the ability of materials to resist scratching by another material.

Open Ended

Use the internet to research where we may use diamond as plumbers

​Diamond core drills:

Many core drills use diamond-tipped bits for enhanced cutting efficiency and durability.

The diamonds provide superior hardness, allowing the drill to penetrate tough materials.

​Conductivity in materials

Open Ended

What do you think conductivity is?

​Conductivity in materials

​Conductivity is the property that enables a metal to carry:

Heat (thermal conductivity)
or
Electricity (electrical conductivity).

​Thermal conductivity:

Heat is transferred from molecule to molecule through the substance.

How fast or how well the heat travels will determine the material’s thermal conductivity.

For example, metals, such as copper, transfer the heat quickly and are said to be good conductors of heat, whereas other materials, such as glass, allow the passage of heat but very slowly and so are poor conductors of heat.

​Electrical conductivity:

This is the ability of a material to allow an electrical charge or current to pass through it.

It is measured in ohms (Ω).

Materials that allow an electrical current to flow freely, such as copper and gold, are known as good conductors, whereas those that do not allow the passage of an electrical current, such as wood, ceramics and PVC, are known as insulators.

Multiple Choice

What is the property of a material that enables it to resist bending, scratching, abrasion, or cutting?

• Conductivity

• Hardness

• Elasticity

• Ductility

Multiple Choice

Which scale is used to assess the hardness of minerals?

• Richter scale

• Mohs scale

• Beaufort scale

• Celsius scale

Multiple Choice

What is the hardest material according to the Mohs hardness scale?

• Quartz

• Talc

• Diamond

• Gold

Multiple Choice

What property allows a metal to carry heat or electricity?

• Hardness

• Conductivity

• Malleability

• Density

Multiple Choice

Which of the following is an example of a material with high thermal conductivity?

• Wood

• Copper

• Plastic

• Rubber

Multiple Choice

Where would a plumber find diamond useful in their working lives?

• Insulation

• Cutting edges

• Electrical wiring

• Decorative purposes