chapter 2

Question 1

definition of physical properties.

Answer 1

physical properties can be measured and observed without changing a material’s composition.

Question 2

definition of electrical conductivity.

Answer 2

electrical conductivity is the measure of how easily electric current pass through a material.

1. good conductors such as metals ( copper an iron ) have high thermal conductivity, they allow electricity to pass through easily
2. poor conductors of electricity such as rubber and plastic are referred to as electrical insulators or insulators of electricity as they do not alllow electric current to pass through easily.

Question 3

definition of thermal conductivity.

Answer 3

Thermal conductivity is the measurement of how easily heat passes through a material.

1. good conductors of heat ( metals ) have high thermal conductivity as they allow heat to pass through easily.
2. poor conductors of heat ( plastic ) have low thermal conductivity as they do not allow heat to pass through easily. Therefore, when we hold the handle of the pan, it does not feel hot.

Question 4

define strength.

Answer 4

Strength is the ability to support a heavy load without changing its shape permanently.

Question 5

define hardness.

Answer 5

Hardness is the material’s resistance to wear and tear and scratches.
If a diamond is harder than a mirror, we say that because the diamond is able to scratch another material. A hard material can scratch a material that is softer than itself.

Question 6

define flexibility.

Answer 6

Flexibility is the ability of a material to bend without breaking and return to its initial shape and size after bending

Question 7

What is melting point?

Answer 7

Melting point is the temperature at which a solid changes into a liquid.

Question 8

What is a boiling point?

Answer 8

A boiling point is the temperature at which a liquid changes into gaseous state

Question 9

What is density?

Answer 9

density is the amount of matter an object occupies in proportion with its volume.

defined by mass per unit volume

Question 10

What is mass?

Answer 10

mass is the amount of matter contained in an object

Question 11

How do we avoid parallax error when using a measuring cylinder?

Answer 11

We should position our eye at the same level as the bottom of the meniscus

Question 12

How do we avoid parallax error when using a ruler?

Answer 12

Our line of sight should be perpendicular to the scale

Question 13

How do we avoid parallax error when using a ruler?

Answer 13

Our line of sight should be perpendicular to the scale

Question 14

Which measuring instrument is the most accurate for measuring length?
1. standard meter ruler
2. measuring tape
3. venire calipers ( digital calipers )

Answer 14

3. The venire calipers can measure up to 0.01 cm (0.1 mm ). While the standard meter ruler can only measure up to 100 cm or 1 m. The measuring tape can measure up to 0.1 cm