Sophia Learning
Sophia: Introduction to Units & Standards: Lesson 4
This lesson should help a learner understand why we use units and how they are governed by standards. It is 4 of 4 in the series titled "Introduction to Units & Standards."
Curated OER
Eternal Egypt: Scale Weight of Green Glass
A scale weight of green glass is in the form of a circle with a round base. It was used as a standard for measuring different weights.