mass  - a measure of the amount of matter in an object, matter - anything that has mass and takes up space, volume - a measure of how much of space an object takes up, weight - a measure of gravitational force on a object, density - how compact a material is; found by dividing the mass of an object by its volume, buoyancy - the upward push of a liquid or gas on an object placed in it,

Lesson 1 : Matter's Structures

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排行榜

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切換範本

恢復自動保存: ?