1.6 Measuring Tools

8/14/2019 1.6 Measuring Tools

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1.6 Measuring Tools

Length is the distance

between two points

Definition of Length

Forms of length :

thickness, height,

depth and breadthLong distance km

Short distance cm ,mmS.I. unit length m

Units of Length


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1. Tools to measure lengthTools for measuring

lengthUses accuracy

1. Metre rule to measure the length ofshort straight lines

0.1 cm

2. Measuring

tape

to measure the length of

long straight lines

3. Thread andmetre rule

to measure the length ofa curved line


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lengthUses accuracy

4. Externalcalipers

to measure the externaldiameter of a sphere orcylindrical object

5. Internalcalipers

to measure the internaldiameter of a cylindrical

object


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length

Uses accuracy

6. opisometer to measure the length ofa curved line

0.1cm

7. Verniercalipers

Very short lengths 0.01 cm


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2. Measuring area

1. Method 1 estimating by graph

i- triangle is regular shapeFigure page 28 Number of squares counted=

Area of each square=

Estimated area of the shape=

Area is a two-dimensional ..

Unit of area cm2

, m2

, km2

S.I unit for area


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ii- bubble is irregular shape

Figure page 28 Number of squares counted=

Area of each square=

Estimated area of the shape=


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The method is as follows:

Trace the shapes onto the graph paper with a pencil.

Count the number of complete squares covered by the

shape.

An incomplete square is counted if half or more of the

square is covered.

Do not count an incomplete square if less than half of the

square is covered.


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2. Measuring area

Method 2 estimating area by formula for regular

shape only

Figure page 28 Area of triangle= x b x h

= x 6 x 4

= 12 cm 2


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2. Measuring area

Figure bulatandengan jejari 2 cm

Area of circle== r2

= x 2 cm x 2 cm

= 12.6 cm2

Figure trapezium Area of trapezium=

= (a + b) x h


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3. Measuring volume

Volume is three-dimensional space occupied byan object

Unit for volume mm3,cm3, m3

volume of a liquid usually in litres (l) or millilitres(ml). 1 l =1000ml

S.l. unit volume is cubic metre (m3).


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3. Measuring volume of liquid

Tools for measuringvolume

Uses accuracy

1. Measuringcylinder

to measure the volume ofliquids

2. Burette to measure a smallvolume of liquids

accurately

0.1 cm3


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3. Measuring volume of liquidTools for measuring

volume of liquid

Uses accuracy

3. Pipette to measure a fixed volumeof liquids accurately

0.1 cm3

4. Suctionpump

Use a suction pump tosuck liquid into a pipette.

Do not use mouth.


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3. Measuring volume of solid

1. METHOD 1 - volume of small irregular objects can be

determined by the displacement method using a

measuring cylinder


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i. The volume of the stone = __________ cm3

ii. The volume of 2 corks = __________ cm3

iii. The volume of 1 cork = __________ cm3

Water displacement method using measuring cylinder


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2. METHOD 2- volume of larger irregular

objects can be measured using a large

displacement can or Eureka can


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3. Measuring volume of solidi. Fill the displacement can with water. Let the excess water

drain away until it settles at the spout

ii. Place an empty measuring cylinder below the spout to

capture the water displaced by the volume of the object

lowered into the can. Read the volume of water in the

measuring cylinder.


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3. METHOD 3 - volume of some objects withregular shape can be calculated using the

formulaeShape Formula for volume

1. CuboidV= l x b x h


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3. Measuring volume of solidShape Formula for volume

2. Cylinder

V = r2h

3. Sphere

V = 4/3 r3


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3. Measuring volume

Shape Formula for volume

4. Cone

V = 1/3 r2h

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1.6 Measuring Tools