Everything Science Grade 10

CHAPTER 2. CLASSIFICATION OF MATTER 2.8

Material Thermal Conductivity

(W·m−^1 ·K−^1 )

Silver 429

Stainless steel 16

Standard glass 1.05

Concrete 0.9 - 2

Red brick 0.69

Water 0.58

Polyethylene (plastic) 0.42 - 0.51

Wood 0.04 - 0.12

Polystyrene 0.03

Air 0.024

Use this information to answer the following questions:

1. Name two materials that are good thermal conductors.

2. Name two materials that are good insulators.

3. Explain why:

a. Red brick is a better choice than concrete for building houses

that need less internal heating.

b. Stainless steel is good for making cooking pots

Magnetic and

Non-magnetic Materials

ESAAJ

We have now looked at a number of ways in which matter can be grouped, such as into

metals, semi-metals and non-metals; electrical conductors and insulators, and thermal con-

ductors and insulators. One way in which we can further group metals, is to divide them

into those that aremagneticand those that arenon-magnetic.

See video: VPaga at http://www.everythingscience.co.za

Chemistry: Matter and Materials 49