CHAPTER 2

MEASURING PROCESS

Measuring thickness and size

Measuring time

Measuring volume

Measuring time

VERNIER CALIPERS

main scaleVernier scale

Screw clampTail (for

measuring depth)

Lower Jaws (for measuring outer dimensions)

Upper Jaws (for measuring inner dimensions)

External jaws

object

Reading on main scale = 3.2 cm

Reading on vernier scale = 0.04 cm

External length of the object:3.2 cm + 0.04 cm = 3.24cm

How to read vernier calipers

Case 1

(Positive zero error)

Case 2

(Negative zero error)

Main scale

Vernier scale

Zero error = +0.06 cm

Main scale

Vernier scale

zero error = -(0.10 – 0.07)cm = -0.03cm

The right measurement:

Case 1: Positive zero error = +0.06cm

External length of the object

= (3.24 – 0.06)cm

= 3.18cm

Case 2:Negative zero error = -0.03cm

External length of the object

= (3.24 + 0.03) cm

= 3.27 cm

Micrometer Screw gauge.To measure short lengths such as the

thickness of paper, the diameter of wire.

Main scale vernier scale

=Main scale =

vernier scale =

Stopwatch~ because able to meaure the short interval of time

~type:* analogue stopwatch* digital stopwatch

Analogue stopwatch

Digital stopwatch

Measuring cylinder

Burette and pipette ( more accurate instrument)

burette pipette

When taking the reading, eye level must be at the bottom of meniscus to avoid parallax error

Thermometer

Analogue Digital

When taking reading in liquid:

~ the liquid must be stir to make sure even heat distributed

~the eye must be under the meniscus

Consistency A set of measurement that are close to each other

Accuracy The degree of precision required of a measurement.

Sensitivity Ability of any instrument to detect small changes in physical quantities

GRAPHTeaching Focus :

Labelling x and y axes Identify variables from graph – manipulated

& responding Stating hypothesis Giving conclusions

A Student carries out an experiment to investigate the relationship between mass of water and the amount of heat absorbed.

Label the x-axis and y axis in the graph given below with the underlined physical quantities.

Type of graph

1. Y direct propotional to x

2. Y is proportional linearly to x(not from origin)

3. Y inversely proportional to x

HOME WORK

Objective questionSubjective question