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Mrs. McCarthy’s MCAS Review. Physical Sciences. Physical Science. 8 th Grade Curriculum Properties of Matter The Atom Elements, Compounds, and Mixtures Motion Forms of Energy & Heat. Properties of Matter. Particle Motion & Phase Changes (15) Mass vs. Weight (1)
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Mrs. McCarthy’s MCAS Review Physical Sciences
Physical Science • 8th Grade Curriculum • Properties of Matter • The Atom • Elements, Compounds, and Mixtures • Motion • Forms of Energy & Heat
Properties of Matter • Particle Motion & Phase Changes (15) • Mass vs. Weight (1) • Volume vs. Mass; Density (2) • Measuring Tools (3) • Conservation of Mass (4) • Melting Point & Boiling Point (9) • Physical & Chemical Changes (10)
Solid • Has a definite shape and a definite volume • Particles are held tightly in place and vibrate in place Looks Like
Liquid • Have a definite volume and no definite shape • Take the shape of a container • Can Pour • Particles slide past one another Looks Like
Gas • Have NO Definite Shape or Volume • Fill their containers • Particles spread out and move independently Looks Like
Plasma • Very high in energy • Plasma has no definite shape or volume • Particles are broken • Plasma is the most common phase of matter in the universe • Examples: Auroras, lightning, fire, neon lights
Charles’ Law • The volume of a gas increases as its temperature increases • For Example: • A balloon expands and pops when it is heated. • A balloon contracts and gets smaller when it is cooled.
Boyle’s Law • The volume of gas increases as the pressure decreases • Example: Piston • Lifting the Plunger Decreases the Pressure • Pushing the Plunger Increases the Pressure
States of Matter Matter changes phases due to a change in the heat energy of an object’s particles. Add Energy/Heat Lose Energy/Heat ←
Measurement • Mass • Weight • Volume • Temperature
Mass • The amount of matter in an object • Doesn’t change with gravity • Measured with a triple-beam balance • SI unit of grams
Inertia • A resistance to a change in motion • The more mass an object has, the more inertia it has • Example: Grocery Carts & Cars
Weight • The amount of gravitational pull on an object • Changes with gravity • Measured in Newtons
Volume • The amount of space an object takes-up • Can be measured with a ruler using the formula: Volume = length * width * height
OR • Volume can be measured with water and a graduated cylinder using displacement • Solid SI Unit of cm³ • Liquid SI Unit of mL
Density • The amount of mass in a given volume • Measured with the Formula: Density = Mass / Volume * Labeled in g/cm³ Mass ______________ Density * Volume
Density Stackers • Many liquid mixtures will stack up into layers by their densities • More dense materials will be below less dense materials • Example: Salad Dressing
Characteristic Properties • Describe substances based upon their characteristics • Example: Physical Properties Chemical Properties
Physical Properties • Physically describe an object based upon observable and measurable observations Examples: COLOR Density Solubility Mass Malleability Texture Volume Temperature State Weight Ductility Melting Boiling
Melting Point & Boiling Point • Each Substance has its own Melting & Boiling Points that are always the same temperature regardless of the size
Particle Motion & Temperature Increases • Melting- the change from a solid to a liquid • Adding energy • Boiling- the change from a liquid to a gas • Adding Energy
Melting Point: All Water Melts at 0˚C Boiling Point: All water boils at 100˚C Melting & Boiling Points
Physical Changes • A change in a substance that affects one or more physical properties of a substance • The substance does not change • Examples: Cutting Hair Crushing a Can Sanding Wood Broken Glass Melting Butter Freezing Water Dissolving Salt Bending Metal
Chemical Properties • Describe substances based upon their ability to change into a new substance with different properties • Chemical properties are not easily observed with your senses and often need to be tested • Examples: Reactivity: Tarnishing, Rusting, Flammability
Chemical Changes • When substances change into new substances with different properties • Examples: Gas Formation & Bubbles Burning Cooking Reactivity
Conservation of Mass • Mass cannot be created or destroyed • Even during a chemical reaction, the mass will remain the same. • Example- Lab with: Vinegar, Baking Soda, Baggies, Film Canister, & T.B.B. Before After
Elements, Compounds, & Mixtures • There are more than 100 elements on the periodic table that make up ALL things (5) • Atoms of Elements vs. Molecules of Compound (6) • Examples of Elements and Compounds (7) • Mixtures vs. Pure Substances (8)
Atomic Theory • Democritus- Proposes the Atom 440 B.C. • Dalton- Atoms are the Smallest Particle • Thomson- “Plum Pudding” with Electrons • Rutherford- Gold Foil → Atom’s Nucleus • Bohr- Electrons Travel in Energy Paths • Schrödinger & Heisenberg- Electron Clouds
Atom • The Smallest Unit of an Element • Everything is made of Atoms Energy Levels Nucleus with Protons and Neutrons Electrons
Protons • Charge: Positive • Mass:1 amu • Location: Nucleus • Proton count determines the element • Protons = atomic number
Neutrons Charge: none Mass: 1 amu Location: Nucleus *To find the neutrons: atomic mass – atomic number
Electrons • Charge: Negative • Mass: Almost Zero • Location: Electron Clouds • Balanced Atoms: Protons = Electrons
Periodic Table • Organized Data of Elements • Organized by Atomic Number • Over 100 Elements • Contains Many Patterns • Element Cube: 2 Atomic Number He Chemical Symbol Helium Element Name 4.0 Atomic Mass
Pure Substances • A substance with only one type of particle • Examples: Elements & Compounds • Pure Substances Cannot be Broken Down and Retain their Properties
Elements Left of zigzag line Right of zigzag line Border the zigzag line
Mixtures • A combination of two or more substances that are not chemically combined. • A mixture is easily separated by physical means • A mixture is NOT a pure substance.
Separating Mixtures Techniques: • Magnet: uses a magnet • Filter: uses a sifter • Centrifuge: uses spinning (densities) • Solutions: uses dissolving • Distillation: uses boiling point
Chemical Reactions • The process where one or more substances changes to become one or more different substances. • LAW OF CONSERVATION OF MASS • Mass is never gained or lost in a chemical reaction
Clues to Chemical Reactions • Gas Formation • Solid Formation • Color Change • Energy Change
Chemical Formulas & Equations • A chemical formula uses symbols and numbers to represent a compound • Chemical Equations uses formulas and symbols to show a chemical reaction • Chemical Equations MUST be Balanced and follow the Law of Conservation of Mass Example: C + O2 CO2
Motion of Objects • Motion is described by Position, Direction, & Speed • Graphs of Distance vs. Time (S= D/T)
Motion Motion A change in an object’s position relative to reference point(s) during a specific length of time
Distance Speed = Time Distance Speed * Time
Velocity Speed an object travels in a given direction The unit label is ALWAYS a: Distance/Time & Direction Word Example: 60 miles/hour West Example Direction Words: North, South, East, West, Left, Right, Up, Down
Force • A push or a pull • Exerted on one object • by another object • Can affect an object’s • speed or direction
Unbalanced forces If the net force on an object is NOT ZERO. The resulting effect is the object changes its motion.
Balanced forces If the net force on an object is ZERO the resulting effect is the object has NO change in its motion.
Friction • Resists Motion Between 2 Objects • Dependent on Texture of Surfaces • 4 major types: Rolling, Sliding, Static, Fluid
GRAVITY Gravity is a force of attraction • Exists between any two objects • The force is dependent upon The size of the objects and the distance they are from one another