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Discover the physical properties and definitions of density, buoyancy, and viscosity in this comprehensive guide. Learn how these factors affect the states of matter and influence their behavior.
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What is Matter? • Anything that has mass and takes up space • So pretty much anything you can imagine – from the air we breathe, to water we drink, to the sun and all the stars.
What are physical properties? • Watch and see!
Two Ways to Measure Matter.. • Mass • Volume
Density is.. • A property that relates mass and volume (combines them) • Density = mass/volume • OR • Density equals mass per unit volume (g/cm3)
Density affects… • Hardness (resistance to scratching) • Elasticity (ability to stretch and return) • Brittleness (likelihood to shatter) • Malleability (ability to made into thin sheets) • Tensile Strength (how much force before breaking)
Density of Fluids • Tend to be less dense than solids • Molecules move around each other • Do not “stack” easily • Water is an exception – ice is less dense than water (due to structure of water)
Density Math • The density of a material can be determined by dividing the mass by the volume • Ex. What is the density of a 400 g block that has a volume of 16 cm3? • Answer: 400/16 = 25 g/cm3
Conversions • Sometimes the mass is given in a unit other than grams. • Or the volume is given in a unit other than mL. • Ex. What is the density of a block that weighs 2.5 kilograms and has a volume of 40 cm3? • The mass must be converted into grams (g) so m= 2500g • Answer: 2500/40 = 62.5 g/cm3
Note… • A cm3 is equivalent to a mL. Specifically, mL is used for volume of gasses and liquids and cm3 is used for the volume of solids.
Definition • The measure of upward pressure a fluid exerts on an object
Buoyancy is… • Determined by density • The denser the fluid, the more buoyant force it applies • Ruled by Archimedes’ Principle • The force exerted on an object by a liquid is equal to the mass of the fluid displaced by that object
Displaced • To move something from its usual place
Therefore… • If buoyant force is greater than the mass of the object, the object FLOATS • If buoyant force is less than the mass of the object, the object SINKS
Neutral Buoyancy • Is achieved when the mass of the object is EQUAL to the mass of the liquid displaced by that object. • The object floats exactly in the position it is placed.
Definition • Measure of a material’s resistance to flow (how hard it is to pour)
Viscosity is determined by… • Size of liquid molecules • Shape of liquid molecules • Temperature of liquid • Also applies to gasses
Therefore… • A thick substance is described as being very viscous • Ketchup, syrup (cold) • Motor oils have different grades based on viscosity (10W-40, 10W-30)
Viscosity of Liquid • As temperature of a LIQUID increases, its viscosity decreases. • The additional kinetic energy allows the molecules to slide past each other with greater ease.
Temperature and gasses • As the temperature of a GAS increases, its viscosity increases. • Because gas molecules are far apart, they do not have to slide over each other very often in order to flow. • Raising the temperature actually increases the number of collisions between the molecules, resulting in an increase in friction and therefore, viscosity
Check it out! • Watch what happens!
4 States of Matter • Solid • Liquid • Gas • Plasma
Solid State • Lowest energy form of matter • Molecules do not change position • Definite Shape • Definite Volume
Liquid State • Molecules can move around each other • Definite volume • Takes shape of container
Gas State • Molecules move freely and separate from one another • No definite shape • No definite volume
Plasma • Most common state of matter (in universe) • Highest energy form of matter • Made up of ionized gas molecules (atoms breaking apart due to high heat/energy)
