Mass [1]
What is Mass?
Here, let's explain the difference between mass and weight.
We sometimes hear the topic "Weight becomes 1/6 on the earth in the moon."
The scale will show ten kilograms when the person of 60 kilograms weighs oneself in the surface of the moon.
Weight decreases when going to the moon because the attraction of the moon is weak.
Even if going to the moon, neither a bone nor a muscular that composes astronaut's body amount decrease.
Only weight became 1/6 though an original amount of the material that composed the human body had not decreased.
If the solid of the metal of 60 kilograms is carried to the surface of the moon, it becomes ten kilograms.
The number of atoms that compose the solid of metal is sure not to change even if going from the earth to the moon.
Only weight changes though an original amount is sure not to change.
"Original amount" doesn't change. "Weight" changes by the place in one side.
Because we live only on the earth, the fact "The weight of the object changes by the place" is not actually felt easily.
Therefore, we separately think about neither "Original amount" nor "Weight".
"Original amount" and "Weight" are different.
"Original amount" is called mass.
Weight changes because gravitation changes if some objects are carried to other heavenly bodies.
However, mass is constant even if going to where.
It is because the number of atoms that compose the objects doesn't change.
The unit of mass is kg.
Kilogram[kg] is a unit of not weight but mass in reality.
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