An object’s mass and its weight are related concepts, but not quite the same. An object’s mass is the amount of matter contained in the object, and the object’s mass is the same whether that object is on Earth or in the zero-gravity environment of outer space.

Where gravity strongly pulls on an object’s mass its weight is greater than it is where gravity is less strong. The substance of the universe—from a grain of sand to a star—is called matter .

ion — atom with an overall positive or negative charge. object’s mass — the amount of matter contained in the object, and the object’s mass is the same whether that object is on Earth or in the zero-gravity environment of outer space. object’s mass its weight — greater than it is where gravity is less strong. matter — physical substance; that which occupies space and has mass.

Be able to discuss the relationships between matter, mass, elements, compounds, atoms, and subatomic particles; distinguish between atomic number and mass number; identify the key distinction between isotopes of the same element.