S OLIDS, L IQUIDS, AND G ASES AND D ENSITY Ms. Copeland Physical Science

S TATES OF M ATTER

K INETIC T HEORY Explains how particles in matter behave 3 assumptions needed: 1. All matter is composed of small particles 2. Particles are in a constant, random motion 3. Particles constantly colliding with each other and their surrounds (container, other particles) Imagine a room full of tennis balls: They are constantly bouncing and hitting walls and each other

T HERMAL E NERGY Causes all particles to vibrate Temperature is directly related with thermal energy and particle vibration Water’s particles vibrate more slowly when in the form of ice and faster when in the form of water vapor. Temperature is the average kinetic energy found in a particle at a given time. How would predict particles to behave at absolute 0 ( °C, 0° Kelvin)?

S OLIDS Most solids have a certain pattern that they must arrange themselves Solids automatically arrange themselves into this pattern when they cool The shape a solid forms will determine it’s chemical properties and can give you clues about these properties Have a definite shape and volume

L IQUIDS Have the ability to flow: they can slide past each other Particles have more kinetic energy than solids Take shape of their container Have a definite volume

G ASES Have so much kinetic energy that they overcome any attractive forces between molecules No fixed volume or shape Have the ability to flow Expand to fill entire container they are in

P LASMA Most common state of matter in the universe Overall neutral charge Move extremely fast, thus have a very high kinetic energy

H OW DO THINGS FLOAT ? Buoyancy is the upward force exerted on an object by a liquid. When a boat floats, water is pushing it up. (pg. 485) Archimedes Principle : An object will displace the same amount of water as it weighs. If an object weighs 5 grams it will displace ___ mL of water When weight and water displaced is equal, an object floats. What about if the weight of an object is more than the water it displaces?. 5

D ENSITY Dependant on how close together particles are Does a block of wood weigh the same as a block of steel? Differences in weight are due to densities. Which would float a wood block or a steel block? Which is denser, the wood block, or the steel block? Objects float when there are less dense than the object they are placed in. Why do steel boats float?