Measurement: FAQ

Mass is the amount of matter in an object. We usually measure it in grams $\text{(g)}$start text, left parenthesis, g, right parenthesis, end text or kilograms $\text{(kg)}$start text, left parenthesis, k, g, right parenthesis, end text.

Volume is the amount of space an object takes up. We can measure it in units like milliliters $\text{(mL)}$start text, left parenthesis, m, L, right parenthesis, end text or liters $\text{(L)}$start text, left parenthesis, L, right parenthesis, end text.

Milliliters are smaller than liters. There are $1{,}000$1, comma, 000 milliliter in $1$1 liter.

A single raindrop contains about $1$1 milliliter of liquid:

This bottle contains about $1$1 liter of liquid:

Grams are smaller than kilograms. There are $1{,}000$1, comma, 000 grams in $1$1 kilogram.

A small paperclip has a mass of about $1$1 gram:

A wooden baseball bat has a mass of about $1$1 kilogram:

Mass is the amount of matter in an object, while weight is the force an object exerts on a scale due to gravity. While mass stays the same no matter where we are, weight can change depending on the strength of gravity. For example, we would weigh less on the moon because the moon's gravity is weaker than Earth's.