Mid-Year Review

1. Mid-Year Review Wednesday March 28 and Thursday March 29 Mrs. McCarthy’s 8th Grade Physical Science

2. Test Set-up • 66 Total Multiple Choice Questions • Including: • 4 Understanding Diagram Questions • 5 Measuring Questions • Many Vocabulary Definitions • 1 Open Response from a choice of 3 Questions

3. Study Tips • Study and Review with previous tests and quizzes (several repeat questions) • Book Walk and Chapter Highlights at the end of each unit • Midyear Exam study guide • Midyear Exam PowerPoint • After-school Extra-help

4. Content Overview • Introduction to Physical Science (Notes/Ch 1 Text) • Scientific Method • Lab Safety • Metric Measurement • Properties of Matter (Chapter 1) • States and Phases of Matter (Chapter 2) • Atoms (Chapter 4) • Periodic Table (Chapter 5) • Elements, Compounds & Mixtures (chapter 3)

5. Scientific Method • An organized series of steps used to answer questions and solve problems. • Ask a Question • Form a Hypothesis • Test the Hypothesis • Analyze the Results • Draw Conclusions • Communicate Results

6. Why do we use the scientific method? • It is an organized way to solve a problem.

7. Measurement • Mass • Weight ● Length & Area ● Volume • Temperature

8. Length Length is a measure of distance. Length is measured with a metric ruler. SI units of length are: Kilometers Meters Decimeters Centimeters Millimeters

9. Mass • The amount of matter in an object • Doesn’t change with gravity • Measured with a triple-beam balance • SI unit of grams

10. Inertia • A resistance to a change in motion • The more mass an object has, the more inertia it has • Example: Grocery Carts & Cars

11. Weight • The amount of gravitational pull on an object • Measured with a spring scale • Changes with gravity • Measured in Newtons

12. Volume • The amount of space an object takes-up • Can be measured with a ruler using the formula: Volume = length * width * height

13. OR • Volume can be measured with water and a graduated cylinder using DISPLACEMENT • Solid SI Unit: cm³ • Liquid SI Unit: mL

14. Surface Area • Area is the amount of surface space • Area = Length * Width • Labeled with a squared (²) measurement • Measurements are found with a ruler

15. Temperature • Temperature is a measurement of heat • Measured with a thermometer • SI unit labels with Kelvin or Degrees Celsius (Degrees Fahrenheit in USA)

16. Density • The amount of mass in a given volume • Measured with the Formula: Density = Mass / Volume * Labeled in g/cm³ Mass ______________ Density * Volume

17. 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 Least Dense Most Dense

18. Characteristic Properties • Describe substances based upon their characteristics: Physical Properties Chemical Properties Statue of Liberty Log of Wood

19. Physical Properties • Physically describe an object based upon observable and measurable observations Examples: COLOR Density Solubility Mass Malleability Texture Volume Temperature State Weight Ductility

20. 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

21. 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

22. Chemical Changes • When substances change into new substances with different properties • Examples: Gas Formation & Bubbles Burning Cooking Reactivity

23. States of Matter Bose-Einstein Condensate (new theory) Plasma

24. Solid • Has a definite shape and a definite volume • Movement: Particles are held tightly in together and vibrate in place Looks Like

25. Liquid • Have a definite volume and no definite shape • Take the shape of a container • Can Pour • Particles slide past one another Looks Like

26. Gas • Have NO Definite Shape or Volume • Fill their containers • Particles spread out and move independently Looks Like

27. 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

28. 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.

29. 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

30. 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

31. Atomic Theory

32. Atom • The Smallest Unit of an Element Energy Levels Nucleus with Protons and Neutrons Electrons

33. Atoms • Very small • Can’t be seen with the naked eye • Only seen with an extremely powerful microscope Scanning Tunneling Microscope is 3.5 million times magnified. The atom was first seen in 1981.

34. Atoms • Everything is made of atoms • Atoms are the most basic form of matter: “Building Blocks of Matter”

35. Protons • Charge: Positive • Mass:1 amu • Location: Nucleus • Proton count determines the element • Protons = atomic number

36. Neutrons Charge: none Mass: 1 amu Location: Nucleus *To find the neutrons: atomic mass – atomic number

37. Electrons • Charge: Negative • Mass: Almost Zero • Location: Electron Clouds • Balanced Atoms: Protons = Electrons

39. Isotopes • Atoms that have the same number of protons but have different numbers of neutrons • Atoms that are isotopes of each other are always the same element because the number of the protons in each atom is the same.

40. Valance Electrons • Electrons in the outermost energy level of an atom. • Valance Electrons are important in determining how an atom will bond to make compounds. • Example: 1 Valance Electron

41. Charges • An atom is neutral with no overall charge because the protons are equal to the electrons. • If an atom gains or loses an electron it becomes unbalanced and is called an ion. Negative Ions have gained electrons Positive Ions have lost electrons

42. Atomic Forces • *Strong Force: Holds Nucleus Together Keeps + nucleus from flying apart • *Electromagnetic Force: opposites attract Keeps - electrons around + nucleus • Gravity: very small because of atom size • Weak or Nuclear Force: radioactive

43. Periodic Table • Organized Data of Elements • Organized by Atomic Number • Contains Many Patterns • Element Cube: An Element Cube Contains specific information about each element on the periodic table 2 Atomic Number He Chemical Symbol Helium Element Name 4.0 Atomic Mass

44. Groups Also called families Vertical Columns on the Periodic Table Elements in the same group have similar properties Periods Horizontal Rows on the Periodic Table Organized by Atomic # Periodic Tableof the Elements

45. Elements Left of zigzag line Right of zigzag line Border the zigzag line

46. Pure Substances • A substance with only one type of particle • Examples: Elements & Compounds • Pure Substances Cannot be Broken Down and Retain their Properties

47. Elements A pure substance that cannot be separated into simpler substances by physical or chemical means Smallest unit is an atom Examples: Iron – Fe Oxygen – O Gold – Au Compounds A pure substance made from 2 or more elements that are chemically combined Smallest Unit is a molecule Examples: Salt - NaCl Water - H2O Carbon Dioxide - CO2 Pure Substances

48. Atom • An atom is the smallest unit of an element. • An atom is a pure substance.

49. Compounds • Compounds are two or more atoms that are combined chemically. • Compounds are a pure substance. • A molecule is the smallest unit of a compound.

50. 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.