Transcript The Metric System - Freehold Borough Schools

Measurement
– A Common Language
The Metric System
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The metric system is a decimal system of
weights and measures.
It is based on the unit of length called the
METER.
The metric system is now called, The
International System of Measurement (SI for
short).
To get the meter, they divided a line from the
north pole to the equator into 10 million
parts!
Why do we use Metric System

No numbers to memorize
 Easy to say and write
 Converts by multiples of 10
Used all around the world
Units of Measurement
Prefixes:
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Kilo = 1000
Hecto = 100
Deca = 10
(Base Unit)= 1
Deci = .1
Centi = .01
Milli = .001
Examples:
 Kilometer
 Hectometer
 Decameter
 (Meter)
 Decimeter
 Centimeter
 Millimeter
Length:
The standard unit of length in the
metric system is the meter.
 Common length units:
1 millimeter = 1 mm
1 centimeter = 1 cm
1 meter = 1 m
1 kilometer = 1km
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Let’s look at the meter:
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1 meter is a little longer than 1 yard or 3 feet.
There are 10 decimeters in 1 meter
There are 10 centimeters in 1 decimeter.
There are 10 millimeters in 1 centimeter
Measuring length – p. 48
The shell of the turtle in figure 2 is 8.8 cms, how
many mms is this?
English to Metric Conversions
****You do not need to know these.
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39,370 inches = 1
kilometer
3280.8 feet = 1
kilometer
.62 miles = 1
kilometer
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1 inch = 2.54 cm
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1 foot = 30.48 cm
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1 yard = .914 m
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1 mile = 1609.3 m
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1 mile = 1.609 km
Let’s Practice
Use the meter stick or the metric ruler to measure
the following: careful when choosing what unit to
measure in…
1.
2.
3.
4.
5.
6.
the
the
the
the
the
the
length of your lab table
length of your science textbook
length of your partners hand
length of your own pinky finger
width of your pinky finger nail
width of your pencil point
Mass
Mass is a measure of how much matter an
object contains.
The basic unit for mass is kilogram.
How many grams = 1 kg?
In the science lab, we will
measure in grams.
But…. what is a gram?
The difference between
MASS and WEIGHT
Weight = the force of gravity on an object.
Mass = the amount of matter an object
contains
120lbs on Earth = 20lbs on the moon
50 kgs on Earth = 50 kgs on the moon
Measuring Mass
Triple Beam Balance – a device for
measuring mass in grams.
Let’s learn the parts of the triple
beam balance and practice measuring
mass. Desktop text p. 49
TIME
The SECOND is the standard SI unit used to measure time.
There are 60 seconds in 1 minute.
There are 60 minutes in 1 hour.
Measuring Volume
Volume - the amount of space an object takes up.
**The standard unit for volume is the liter
•Volume of liquid = pour liquid into graduated
cylinder and measure amount
•Volume of regular shaped solids = length x
width x height in cms (cm3)
•Volume of irregular shaped solids (like a rock)=
water displacement.
DENSITY
Density = mass
volume
unit = g/cm3
= g/ml
p. 52 Let‘s READ. 
p.53 Densities of common substances. Once
you know an objects density, you can
determine whether or not the object will float
in a given liquid.
Look at the chart, what is the density
of water? Will Aluminum sink or float
in water? Explain how you know
What is the density of a pencil with a
volume of 4ml, and a mass of 24g?
What is the density of an object with a
volume of 12cm3, and a mass of 36g?
Let’s find the Mass and Volume of our two wooden
cubes…
The density of water is 1g/cm3 or 1g/ml (1ml = 1cm3)