Lab 1
UNITS, DIMENSIONS, ERROR CALCULATION, GRAPHING
1.
UNITS
In order that measurement may be meaningful to every body, units of measurements are
standardized internationally. Such a system of units is called System Internationale (S.I).
The following are some of the commonly used S.I units.
Quantity measured
Unit used
abbreviation
Length
Meter
M
Mass
Kilogram
Kg
Time
Second
s
Electric Current
Ampere
A
Temperature
Kelvin
K
Length is measured using a meter ruler. For measuring small lengths or distances a meter
is divided into smaller units such as the centimeter (cm), millimeter (mm), micrometer
(
µ
m), nanometer (nm), picometer (pm) etc. Long distances are measured in kilometers
(km)
10
2
cm
=
1 m
1 cm = 10
-2
m
10
3
mm
=
1 m
1 mm = 10
-3
m
10
6
µ
m
=
1 m
1
µ
m = 10
-6
m
10
9
nm
=
1 m
1 nm = 10
-9
m
10
12
pm =
1 m
1 pm = 10
-12
m
1 km
=
1000 m
In a similar way a kilogram is divided into grams (g), milligram (mg), microgram (
µ
g),
nanogram (ng) and so on. There are different forms of laboratory scales that you may use
to measure mass. The most popular is the electronic balance that you see along the side
benches.
Question:
Make a table as above showing the relation between kilogram and its
smaller units.
1 kg
= ………….g
1 g
=………….kg
1 kg
=…………..mg
1 mg =………….kg
1 kg
=…………..
µ
g
1
µ
g
=………….kg
Temperature is measured using a thermometer. The thermometer used in the laboratory is
marked in degree Celsius (
o
C)

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