Units of weight
Units of weight measure how heavy an object is.
The Metric System of Measurements uses the mass units: gram (g), kilogram (kg) and tonne (t).
1 g = 1000 mg (1 gram = 1000 milligrams )
1kg = 1000 g (1 kilogram = 1000 gram)
1 t = 1000 kg (1 tonne = 1000 kilogram)
From the gram, we get the rest of the metric units using the standard metric prefixes.
A paper clip has a mass of about gram.
A liter bottle of water has a mass of kilogram (plus a little bit extra for the plastic).
Measured scales
https://www.transum.org/Maths/Activity/Units/Default.asp?Level=4