SI Measurement
SI
Measurement
The SI (System Internationale)
system of measurement is the standard measurement system used in
science.
The base or standard unit of mass (amount of matter) is the gram.
The base or standard unit of length is the meter.
The base or standard unit of volume is the liter.
The base or standard unit of time is the second.
The base or standard unit of temperature is degrees celsius.
The SI system is a base 10
system of measurement.
The following acronym may be
helpful in understanding the SI system.
King Henry Died Unfortunately drinking chocolate milk.
The starting letter in each
word stands for the prefix (beginning part) of a unit of measurement.
K
|
H
|
D
|
u
|
d
|
c
|
m
|
stands
for |
stands
for |
stands for |
stands
for |
stands for |
stands
for |
stands
for |
| Kilo- |
Hecto- |
Deko- |
units |
deci- |
centi- |
milli- |
| which means |
which means |
which means |
the base
unit of measurement |
which means |
which
means |
which
means |
| One Thousand |
One Hundred |
Ten |
One Tenth |
One
Hundredth |
One
Thousandth |
| (1000) |
(100) |
(10) |
(1) |
(0.1) |
(0.01) |
(0.001) |
To convert between units, simply
multiply or divide by a multiple of 10 as shown in the table. An easy way to keep conversions
straight is to move the decimal point left or right between these
prefixes. For example, to convert from Kilograms to grams, multiply by
1000 or simply move the decimal point 3 places to the right. 5
kilograms is equal to 5000 grams.
A derived unit cannot be
measure directly, but is calculated instead. Density is an example of a
derived unit. Density is the mass of an object divided by the volume (D
= m/v).
Volume may be measured
directly using a graduated cylinder or volume may be calculated using
the rules of geometry. For example, the volume of a box is length times
width times height (V = l x w x h). A box 30 cm long, 20 cm wide, and
10 cm high has a volume of 30 x 20 x 10 cm3 or 600 cm3. 1 cm3 = 1 ml, the volume may also be expressed as 600 ml or 0.6 L.
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