Year 9 Science · Unit 2 · Lesson 02

Physical Properties of Materials

Foundation Worksheet

Name

Date

Class

Learning Goals

Name and define the key physical properties of materials
Identify how each property is measured and its unit
Distinguish physical properties from chemical properties

Warm Up

Fill the gap

Choose the correct word from the word bank to complete the passage below. Not all words will be used.

hardness tensile strength density conductivity threshold melting point trade-off reactivity solubility

Physical properties can be measured without changing the chemical identity of a substance. One of the most familiar physical properties is , which measures how much mass is packed into a given volume, it is recorded in g/cm³. A material's resistance to being scratched is called its , and can be ranked using the Mohs scale from 1 (talc) to 10 (diamond). When engineers need a material that can withstand pulling forces without snapping, they look at , measured in megapascals (MPa). How well a material transfers heat or electricity is described by its metals generally have high values here while non-metals are used as insulators. When using a data table, engineers set a minimum or maximum for each critical property, then eliminate materials that fail it. Improving one property often requires a for example, adding carbon to steel increases hardness but reduces flexibility. Finally, the temperature at which a solid turns to liquid, its tells engineers how well a material will perform under high-heat conditions such as a jet engine or a furnace.

Your Turn

True or False? Fix the false ones

Circle T or F for each statement. If the statement is false, rewrite it correctly on the line below.

Malleability and ductility are the same property, both describe metals that can be bent without breaking.

Correct it:

Diamond has the highest hardness on the Mohs scale, rated 10.

Correct it:

A material with high electrical conductivity would be a good choice for use as an insulator in electrical wiring.

Correct it:

Density is measured in grams per cubic centimetre (g/cm³).

Correct it:

A material's melting point is a chemical property because heating it changes the substance into something new.

Correct it:

Show What You Know

1. Name TWO physical properties that a materials scientist would measure when selecting a metal for use in overhead electrical power lines. Explain why each property matters for this application.

Recall 2 marks

2. A student says: "A bigger piece of steel is denser than a small piece of steel." Is the student correct? Explain your answer using the definition of density.

Recall 2 marks

Wrap Up

In one sentence, what was the main idea of this lesson?