Chapter 2 Exploring diversity of Matter by its Physical Properties

Physical properties of a material are qualities that can be detected using: Five senses

Measuring devices

For example: Hardness

Strength

Flexibility

Transparent and etc

Physical Properties of Matter

Physic properties of material may different with one another material.

We measure and study physical properties in order to choose right material to serve specific purpose.

For example:

Can we use paper to build car?

Can we use plastic to build house?

Physical Properties of Matter

In order to choose the right material, we should ask ourselves some questions:

What purpose does this object serve?

What physical properties does this object need to have?

Does it need to be strong?

Does it need to be flexible?

It this material costly?

Physical Properties of Matter

Physical Properties of Matter

Umbrella

What purpose does this object serve?

• a device for protection against the rain

What physical properties does this object need to have?

• Waterproofing• Light• Flexible

Plastic

Is it costly?

1. What is definition of physical properties? Giving 3

example

2. What question we should consider before choose a

material for manufacturing an object?

Exercise 2.1

Flexibility is ability of material to: Bend without breaking

Return to its original size and shape after bending

Type of Physical Properties

Hardness of a material is its ability to withstand scratches:

Material can cut or scratch a material less hard than itself

Type of Physical Properties

Melting point of a material is the temperature at which it changes in state from a solid to liquid

Boiling point of a material is the temperature at which it changes in state from liquid to gas

Type of Physical Properties

Strength is ability of material to support a heavy load without breaking or tearing

Electrical conductivity of a material is a measure of how readily electricity passes through it.

Electricity conductor: material allow electricity pass through it easily

Insulator/poor electricity conductor: material does not allow electricity pass through it easily

Type of Physical Properties

Thermal or heat conductivity of a material is a measure of how readily heat passes through it Heat conductor: material allow

heat pass through it easily

Heat Insulator/poor heat conductor: material does not allow heat pass through it easily

Type of Physical Properties

Density of a material is the quantity of matter packed into a unit volume of material

1. What is the different between hardness and strength?

2. Ice-cream melt at 25 degree calcius, from the statement what physical properties of ice- cream shown?

3. Carmen’s Iphone 6 accidently fall on the cement floor and scratched. Which material had better hardness?

Exercise 2.2

Length, Mass, temperature, time and etc.

Unit of measurement:

21 kilograms

21 metres

SI unit – a international system of unit

To ensure our measurement fair and objective

Measurement of Physical properties

UnitNumerical

value

Physical quantity SI unit Symbol

Length metre M

Mass Kilogram Kg

Temperature Kelvin K

Time Second s

SI unit

Prefix Symbol Value

Kilo k 1000

Centi C 0.01

milli M 0.001

Common prefixes

Length is the distance between two specified point.

SI unit : metre

Measurement of length include:

Height

Width

Depth

Thickness

Circumference

Length

Instrument for measuring length

Measuring tape

Measure length greater than 1 m

Two type: 1. Steel measuring tape for rigid and straight surface

2. Flexible measuring tape for curve surface

Metre rule

Measure length up to 1 m

Common used in class room or laboratory

Length

Vernier caliper

Used to measure short length, diameter, internal diameter, depth of object up to 10 cm

Smallest division is 0.01 cm

Length

Length

Main Scale Reading: 2.8cmVernier Scale Reading: o.06 cmReading: 2.86 cm

1 kilogram 1 km 1000m

1 centimetre 1cm 0.01m

1 millimetre 1 mm 0.001 m

1 micrometre 1 μm 0.000001

Length: useful conversion

Exercise 2.3 Question 1

Exercise 2.3 Question 2

Mass is a measurement of the quantity of matter in a body

Mass measurement instrument:

1. Beam Balance

Mass

2. Electronic Balance

Most common measurement instrument

Mass

1t = 1000kg

1kg = 1000 g

1g = 1000 mg

Mass - Useful conversion

SI unit: 𝑚3

Volume of liquid: Measure by measuring cylinder

Volume - liquid

Parallax error

Parallax error

Meniscus

Measure of width, length and height of regular solid

Volume – regular solid

4𝑚 × 5𝑚 × 12𝑚= 240 𝑚3

Can be measure by displacement of irregular solid

Volume – irregular solid

Density

Density of a material is the quantity of matter packed into a unit volume of material

Density = 𝑴𝒂𝒔𝒔

𝑽𝒐𝒍𝒖𝒎𝒆

SI unit 𝑘𝑔

𝑚3

The lower density liquid/ object will float over higher density liquid/object

1. A 50g chicken egg has a density of 2 g/cm3. Find the volume.

2. Given water density is 1𝑔

𝑐𝑚3 . The egg will float or sink

in the water?

Exercise 2.4

1𝑔/𝑐𝑚3=1𝑔

1𝑐𝑚3 =0.001 𝑘𝑔

1 𝑐𝑚×1𝑐𝑚×1𝑐𝑚

=0.001 𝑘𝑔

0.01𝑚×0.01𝑚×0.01𝑚

=0.001 𝑘𝑔

0.000001𝑚3 = 1𝑘𝑔

𝑚3

Volume – useful conversion