mass and weight

Mass and weight may seem like the same thing, but in fact these two measurements are very different. Mass is the total amount of matter, or "stuff," in an object. Weight is the force of gravity on an object. Mass always stays the same, but weight can change depending on how much gravity is acting upon an object.

Mass: how much matter, or stuff, something has inside it
Weight: the amount of gravity that is pulling on
an object
How they're measured: mass is measured in kilograms and weight is measured in newtons
Cool fact: Any two masses have a gravitational attraction for one another, and the greater the mass, the greater the pull.

Image credits: main image: Eric Hamilton.