# SI Units and Measurements

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## SI Units and Measurements SI stands for SYSTEM INTERNATIONALE

Since we needed to use SI units to explain both the gap around someone’s bicep as well as the distance around Earth, we must have the possibility to change the size of the unit to fit the measurement. Scientists designed a system of prefixes that multiplies the vase unit by factors of 10. SI unit can use for measurements big and small by switching the prefix.

## SI Base Units

Quantity Measured SI Unit (Symbol)
length (or distance) meter (m)
mass gram (g)
weight (or force) newton (N)
volume (or capacity) liter (L)
temperature Kelvin (K)
time second (s)
electric current ampere (A)
amount of substrate mole (mol)
light intensity candela (cd

Since we needed to use SI units to explain both the gap around someone’s bicep as well as the distance around Earth, we must have the possibility to change the size of the unit to fit the measurement. Scientists designed a system of prefixes that multiplies the vase unit by factors of 10. SI unit can use for measurements big and small by switching the prefix.

SI PREFIX (symbol) MULTIPLIER
giga - (G) 1,000,000,000
mega - (M) 1,000,000
kilo - (k) 1,000
hecto - (h) 100)
deca - (da) 10
[base unit] 1
deci - (d) 0.1
centi - (c) 0.01
milli - (m) 0.001
micro - (μ) 0.000001
nano - (n) 0.000000001

## SI Unit Conversions

Because the SI prefix system relies on powers of 10, it is easy to convert between units. It is easy to convert between units because the SI prefix system relies on power of 10. We can move the decimal point to the right as many places as the difference in place value if we converting to a smaller unit of measurement. Also, we can move the decimal point to the left as many places as the difference in place value if we are converting to a larger unit of measurement.

## Types of Measurement

LENGTH: Distance between two points
VOLUME: The amount of space something occupies
MASS: The amount of matter in a liquid, solid, or gas
WEIGHT: The force exerted by a mass
DENSITY: The amount of matter in a volume.
TEMPERATURE: How hot or cold something is. While the SI unit for temperature is Kelvin, most scientists use the SI-derived unit, Celsius, to measure temperature.
Kelvin Celsius Fahrenheit
Boiling Point of Water 373.15k 100°C 212°F
Human Body Temperature 310.15k 37°C 98.6°F
Warm Day Temperature 298.15k 25°C 77°F
Absolute Zero 0k -273.15°C -459.67°F
TIME: The period between events, or how long something lasted. The SI unit for time is seconds. Other units for time include hours, days, months, and years.