1.6 measuring tools
TRANSCRIPT
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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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1. Tools to measure lengthTools for measuring
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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1. Tools to measure lengthTools for measuring
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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3. Measuring volume of solid
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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3. Measuring volume of solid
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. Measuring volume of solid
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