Units of Mass/Weight
Metric & Imperial
Weight and mass can often be referred to as the same, but there is a difference between them.
Mass is the overall size of an object.
The weight of an object, depends on how much force from gravity is acting on it, and the force of
gravity is something that can change.
The mass of an object doesn't change, but the weight of an object can, depending on its location with regards to gravity.
Mass and Weight Difference
Example
For a basic example, the force of gravity on the moon, is not as strong as the force of gravity on
Earth.
As such, an astronaut would weigh less standing on the moon, than standing on Earth.
However the astronauts mass would be the same on both the moon and the Earth, so the astronaut would
still be the same size on both the Earth and moon.
When we weigh an object here on Earth, we are really getting an approximation of the objects mass.
Here is a link to a wikipedia page about weight and mass
that goes into a bit more detail about the difference between them.
Another useful page on weight and mass can be seen at thecalculatorsite.com
website.
Units of Mass/Weight, Imperial
When weighing an object on Earth, it is common to use units of mass, as it's really the mass of the
object that's being approximated.
The main imperial units used for measuring weight are:
OUNCE , POUND , STONE , TON
OUNCE
An ounce is a very light weight, notation ( oz ).
A slice of bread will usually weigh around 1 ounce.
POUND / STONE
A pound is a unit equal to 16 ounces. Notation for pound is "lb".
The weight of human beings is often measured in pounds.
One stone is equal to 14 pounds.
TON
An Imperial Ton is not the same as a Metric Tonne, which is referred to further on in the page.
An Imperial Ton is equal to 2'000 pounds, and can sometimes be called a "Short Ton".
There is also a "Long Ton", more prevalent in the US, which is equal to 2'240 pounds.
Units of Mass/Weight, Metric
The metric units used to measure weight are:
MILLIGRAM , GRAM , KILOGRAM , TONNE
MILLIGRAM / GRAM
Like an imperial ounce, a gram is also a very light weight, made up of 1'000 milligrams.
A dime coin usually weighs just over 2 grams.
Notation for milligrams and grams is "mg" and "g".
KILOGRAM
One kilogram ( 1Kg ), is 1'000 grams.
A standard pineapple fruit weights around 1 Kg.
TONNE
A metric tonne is 1'000 Kg.
It is a unit that is used to weigh very heavy objects.
A pick up truck weighs around 2 tonnes.
The titanic ship weighed over 42'000 tonnes.
Conversions
Below are some conversions that can be handy to know.
1 OUNCE = 28.35g , 1 POUND = 0.4536Kg
1g = 0.0353oz , 1Kg = 2.2046lb

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