Glossary
Archimedes' Principle
States that the buoyant force on a submerged or floating object is equal to the weight of the fluid displaced by the object.
Example:
According to Archimedes' Principle, a rock sinks because the weight of the water it displaces is less than the rock's own weight.
Buoyancy
The upward force exerted by a fluid that opposes the weight of an immersed object.
Example:
A boat floats on water due to buoyancy, which counteracts its weight.
Buoyant Force
The upward force exerted by a fluid on an object immersed in it, caused by the pressure difference between the top and bottom of the object.
Example:
When you push a beach ball underwater, the strong buoyant force pushes it back up to the surface.
Density
A measure of how much mass is contained in a given volume, calculated as the ratio of an object's mass to its volume (ρ = m/V).
Example:
A small lead fishing weight has a high density because a lot of mass is packed into a tiny space, causing it to sink quickly.
Extensive Property
A physical property of a system that depends on the amount of substance present.
Example:
The extensive property of mass means that a larger block of wood will have more mass than a smaller one.
Intensive Property
A physical property of a system that does not depend on the amount of substance present.
Example:
The boiling point of water is an intensive property; it's 100°C whether you have a cup or a gallon.
Mass
A fundamental property of matter that quantifies the amount of 'stuff' an object contains and its resistance to acceleration.
Example:
A bowling ball has a much larger mass than a tennis ball, making it harder to accelerate.
Specific Gravity
The ratio of a substance's density to the density of a reference substance (typically water), indicating whether an object will float or sink.
Example:
If a material has a specific gravity of 0.8, it means it's 80% as dense as water and will float with 80% of its volume submerged.
Volume
The amount of three-dimensional space an object occupies.
Example:
The volume of a swimming pool determines how much water it can hold.