Review of 8 th Grade Physical Science Content Standards

Transcription

1 Student Name: Page 1 STANDARD #1: Motion (8 items, 13%) 1) The velocity of an object is the rate of change of its position. As a basis for understanding this concept: a) Students know position is defined in relation to some choice of a standard reference point and a set of reference directions. b) Students know that average speed is the total distance traveled divided by the total time elapsed and that the speed of an object along the path traveled can vary. S = D D = S x T T = D Average Speed T S Constant Speed c) Students know how to solve problems involving distance, time, and average speed. S = D T Ex Problem: If you traveled a distance of 100 miles & you were going at an average speed of 50 miles per hour, how long will it take you to get to your destination? T = D = 100 mi S 50 mi/hr = mile units cancel = 2 hr d) Students know the velocity of an object must be described by specifying both the direction and the speed of the object. V = D Velocity = Speed in a given direction Ex: 25 miles per hour East T Ex Problem: What is the velocity of a car that traveled a total of 75 kilometers north in 1.5 hours? V = 75 km = 50 km/hr 1.5 hr

2 Student Name: Page 2 e) Students know changes in velocity may be due to changes in speed, direction, or both. Increasing Speed Decreasing Speed Changing Direction (Turning) f) Students know how to interpret graphs of position versus time and graphs of speed versus time for motion in a single direction. Time vs. Distance Graph (stopped) Speed vs. Time Graph (increasing) (decreasing) (speed stays the same) Distance (m) Time (s) STANDARD #2: Forces (8 items, 13%) Weight is Not = to Mass Not the Same Concept Newton s 3 Laws of Motion: 1) Law of Inertia 2) F = M x A M = F A = F A M 3) For every action there is an equal but opposite reaction (rockets) 2) Unbalanced forces cause changes in velocity. As a basis for understanding this concept: A Force is a Push or a Pull a) Students know a force has both direction (the course or line along which something moves, lies, or points) and magnitude (greatness of size or extent). b) Students know when an object is subject to two or more forces at once, the result is the cumulative effect of all the forces. Like Adding (+) and Subtracting (--) Numbers Ex: 5 N + 10 N = 15 N Ex: 5 N + 10 N = 5 N

3 Student Name: Page 3 c) Students know when the forces on an object are balanced, the motion of the object does not change. Ex: 5 N + 5 N = 0 N (balanced) d) Students know how to identify separately the two or more forces that are acting on a single static object, including gravity, elastic forces due to tension or compression in matter, and friction. Ex: Bridges Air Resistance Friction: Fluid Friction, Sliding Friction, Rolling Friction, Static Friction e) Students know that when the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction). f) Students know the greater the mass of an object, the more force is needed to achieve the same rate of change in motion. More Mass, More Force is required to move it Momentum = Mass x Velocity Mo = M x V g) Students know the role of gravity in forming and maintaining the shapes of planets, stars, and the solar system. Centripetal Force Forward Motion & Gravity due to Centripetal Force STANDARD # 3: Structure of Matter (9 items, 15%) 3) Each of the more than 100 elements of matter has distinct properties and a distinct atomic structure. All forms of matter are composed of one or more of the elements. As a basis for understanding this concept: a) Students know the structure of the atom and know it is composed of protons, neutrons, and electrons.

4 Student Name: Page 4 b) Students know that compounds are formed by combining two or more different elements and that compounds have properties that are different from their constituent elements. 2H2 + O2 2H2O (stoichiometry, balanced equation) c) Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers. Crystal Structure of NaCl Example of a Long-chain Polymer d) Students know the states of matter (solid, liquid, gas) depend on molecular motion. e) Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently.

5 Student Name: Page 5 f) Students know how to use the periodic table to identify elements in simple compounds. NAME SYMBOL NAME SYMBOL NAME SYMBOL 1 Aluminum Al 10 Hydrogen H 19 Platinum Pt 2 Bromine Br 11 Iodine I 20 Potassium K 3 Calcium Ca 12 Iron Fe 21 Silicon Si 4 Carbon C 13 Lead Pb 22 Silver Ag 5 Chlorine Cl 14 Mercury Hg 23 Sodium Na 6 Chromium Cr 15 Neon Ne 24 Sulfur S 7 Copper Cu 16 Nickel Ni 25 Tin Sn 8 Gold Au 17 Nitrogen N 26 Tungsten W 9 Helium He 18 Oxygen O 27 Uranium U 28 Zinc Zn STANDARD #4: Earth in the Solar System (Earth Science) (7 items, 12%) 4) The structure and composition of the universe can be learned from studying stars and galaxies and their evolution. As a basis for understanding this concept: a) Students know galaxies are clusters of billions of stars and may have different shapes. Shapes: Spiral (We re in the Milky Way Galaxy. Andromeda Galaxy is the next Spiral us), Elliptical, Barred Spiral, Irregular Milky Way Milky Way Galaxy in Relation to Andromeda Galaxy

6 Student Name: Page 6 Spiral Galaxy (ex: Milky Way) Elliptical Galaxy Barred Spiral Galaxy Irregular Galaxy b) Students know that the Sun is one of many stars in the Milky Way galaxy and that stars may differ in size, temperature, and color. Hertzsprung-Russell Diagram shows the relationship between the surface temperatures (x-axis, horizontal axis) of stars & their absolute brightness (y-axis, vertical axis) Our Sun is a medium sized star c) Students know how to use astronomical units and light years as measures of distances between the Sun, stars, and Earth. AU = 9 million miles or 150,000,000 Km Light Year = 300,000 Km/s Distance of Earth is 1 AU from the Sun

7 Student Name: Page 7 d) Students know that stars are the source of light for all bright objects in outer space and that the Moon and planets shine by reflected sunlight, not by their own light. Stars are Luminescent they give off light Moons are just Reflectors of Star light Remember the song Twinkle, Twinkle Little Star e) Students know the appearance, general composition, relative position and size, and motion of objects in the solar system, including planets, planetary satellites, comets, and asteroids. Sun Mercury Venus Earth Mars (Asteroid Belt) Jupiter Saturn Uranus Neptune.39 AU.72 AU 1.0 AU 1.5 AU 5.2 AU 9.6 AU 19.2 AU 30.0 AU Way to remember the Planets: My very eager mother just served us noodles (nachos). STANDARD #5: Reactions (7 items, 12%) 5) Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept: a) Students know reactant atoms and molecules interact to form products with different chemical properties. 2H2 + O2 2H2O Reactants Product b) Students know the idea of atoms explains the conservation of matter: In chemical reactions the number of atoms stays the same no matter how they are arranged, so their total mass stays the same. Ex 1: 2H2 + O2 2H2O (stoichiometry) Mathematically you must have the same number of atoms on both sides of the equation. Ex 2: The original equation is Na + Cl = NaCl. The thing is, chlorine is one of 7 elements that doesn't like to be alone, so it's always 'Cl2', making the equation Na + Cl2 = NaCl. However, this is no longer balanced. So what you do is add a '2' onto NaCl, making it Na + Cl2 = 2NaCl. Now the chlorine is balanced, but the sodium isn't. After that, to balance the sodium, you add a '2' in front of 'Na' making the equation 2Na + Cl2 = 2NaCl. It is now balanced. Ex 3: S + O2 SO3 1 S 1 S Unbalanced 2 O 3 O

8 Student Name: Page 8 2 S + 3 O2 2 SO3 Balanced 2 S 2 S 6 O 6 O Ex 4: 1 C3H8 + 5 O2 3 CO2 + 4 H2O Balanced Burning of Propane Ex 5: 1 CH4 + 2 O2 1 CO2 + 2 H2O Balanced Burning Methane Gas Get More Practice: c) Students know chemical reactions usually liberate heat or absorb heat. Liberate Heat = Exothermic = feels hot ex: a lit candle Absorbs Heat = Endothermic = feels cold ex: baking soda & vinegar reaction In a chemical reaction or change, a new substance is produced. Energy changes occur. Ex: The brown crust on a toasted marshmallow is the result of sugar changing to a mixture of different substances called caramel. d) Students know physical processes include freezing and boiling, in which a material changes form with no chemical reaction. Physical Change: A change in a substance that does not change its identity. One or more physical properties of the material are altered, but the chemical composition remains the same. In physical change, you can dissolve, bend, crush, break, chop, filtrate, distill, and anything else that changes only the shape or form of matter. A physical property is observed with the senses and can be determined without destroying the object. For example: color, shape, mass, length, density, specific heat and odor are all examples of physical properties. e) Students know how to determine whether a solution is acidic, basic, or neutral. ACID Hydrogen Ion (H + ) Lost e-, wants to grab an e- Sour taste Turns blue litmus paper red Squeaky clean feel BASE Hydroxide Ion (OH - ) Gained an e- Bitter taste Turns red litmus paper blue Slippery feel STANDARD #6: Chemistry of Living Systems (Life Science) (3 items, 5%) 6) Principles of chemistry underlie the functioning of biological systems. As a basis for understanding this concept: a) Students know that carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organisms.

9 Student Name: Page 9 Carbon has 4 Valence Electrons = 4 bonds b) Students know that living organisms are made of molecules consisting largely of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. Remember, the human body is made of about 99% CHNOPS c) Students know that living organisms have many different kinds of molecules, including small ones, such as water and salt, and very large ones, such as carbohydrates, fats, proteins, and DNA. A molecule can have as little as 2 atoms and as many as billions of atoms. Small Water Molecule Carbohydrate (Glucose) Long Chain DNA Long Chain STANDARD #7: Periodic Table (7 items, 12%) 7) The organization of the periodic table is based on the properties of the elements and reflects the structure of atoms. As a basis for understanding this concept: a) Students know how to identify regions corresponding to metals, nonmetals, and inert gases.

10 Student Name: Page 10 Noble Gases = Inert Gases b) Students know each element has a specific number of protons in the nucleus (the atomic number) and each isotope of the element has a different but specific number of neutrons in the nucleus.

11 Student Name: Page 11 Carbon Isotopes Periodic Table Trends: c) Students know substances can be classified by their properties, including their melting temperature, density, hardness, and thermal and electrical conductivity. Example: Name: Iron Symbol: Fe Atomic Number: 26 Atomic Mass: amu Melting Point: C ( K, F) Boiling Point: C ( K, F) Number of Protons/Electrons: 26 Number of Neutrons: 30 Classification: Transition Metal Crystal Structure: Cubic 293 K: 7.86 g/cm 3 Color: Silvery STANDARD #8: Density and Buoyancy (5 items, 8%) 8) All objects experience a buoyant force when immersed in a fluid. As a basis for understanding this concept: Gravity An object floats when the buoyant force is greater than gravity Buoyant Force

12 Student Name: Page 12 a) Students know density is mass per unit volume. D = M V b) Students know how to calculate the density of substances (regular and irregular solids and liquids) from measurements of mass and volume. Irregular solids Use the displacement method and subtract the difference: Regular Solids V = L x W x H In this example the volume of the object is 2 ml. c) Students know the buoyant force on an object in a fluid is an upward force equal to the weight of the fluid the object has displaced. If an object displaces 5 N of water, then the buoyant force = 5 N

13 Student Name: Page 13 d) Students know how to predict whether an object will float or sink. (Water =1 g/ml=1 g/cm 3 ) Density less than 1.0 g/ml will float in water, Density greater than 1.0 g/ml will sink in water. You can do this by observation, but be careful as some rocks float (pumice) and some woods sink (cocobolo) Densities of Some Common Gases Density of Some Common Liquids GAS DENSITY TYPES OF LIQUID DENSITY: g/ml or g/cm 3 Air/air.0013g/cm 3 Rubbing Alcohol.81 g/ml Helium g/cm 3 Cooking Oil.92 g/ml Hydrogen g/cm 3 Mercury 13.6 g/ml Nitrogen g/cm 3 Gasoline.66 g/ml Oxygen.0013 g/cm 3 Sea Water 1.03 g/ml Carbon Dioxide g/cm 3 Corn Syrup 1.38 g/ml Milk 1.03 g/ml Densities of Some Solids SOLID DENSITY g/cm 3 SOLID DENSITY g/cm 3 Gold 19.3 g/cm 3 Titanium 4.51 g/cm 3 Lead 11.3 g/cm 3 Platinum 21.4 g/cm 3 Silver 10.5 g/cm 3 Uranium 18.7 g/cm 3 Chromium 7.14 g/cm 3 Wood: Balsa.11 g/cm 3 Cooper 8.9 g/cm 3 Wood: Pine.36 g/cm 3 Iron 7.9 g/cm 3 Wood: Redwood.40 g/cm 3 Steel 7.8 g/cm 3 Wood: Mahogany.45 g/cm 3 Aluminum 2.7 g/cm 3 Wood: Cherry.50 g/cm 3 Rubber Washer 1.34 g/cm 3 Wood: Walnut.53 g/cm 3 Plastic.93 g/cm 3 Wood: Red Oak.673 g/cm 3 Water (ice).92 g/cm 3 Wood: Sugar Maple.689 g/cm 3 Table Salt 2.2 g/cm 3 Wood: Cocobolo 1.10 g/cm 3 Diamond 3.52 g/cm 3 Wood: Ironwood 1.30 g/cm 3 STANDARD #9: Investigation and Experimentation (6 items, 10%) 9) Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:

14 Student Name: Page 14 a) Plan and conduct a scientific investigation to test a hypothesis. Scientific Method: Scientific Method Song: Steps of the Scientific Method: Scientific Method Explained: Title Statement of the Problem (Purpose / Ask a Question) Hypothesis (Form a Hypothesis & Make a Prediction) Materials Procedure (Conduct an Experiment) Results (Collect Data) Conclusions (Analyze Data / Information & Draw Conclusion) (Repeat the work) b) Evaluate the accuracy and reproducibility of data. If you do an experiment, can somebody else get the same results? This is similar to a good chocolate chip cookie recipe. Any baker who follows the recipe precisely will come up with great chocolate chip cookies every time because the recipe is a good one. c) Distinguish between variable and controlled parameters in a test. Variable changes Control always stays the same d) Recognize the slope of the linear graph as the constant in the relationship y = kx and apply this principle in interpreting graphs constructed from data. Slope = Rise Run e) Construct appropriate graphs from data and develop quantitative statements about the relationships between variables.

15 Student Name: Page 15 Making Science Graphs & Interpreting Data: Answers These Questions About Graph a) How many total miles did the car travel? b) What was the average speed of the car for the trip? c) Describe the motion of the car between 5 & 12? d) What direction is represented by line CD? e) How many miles were traveled in the 1 st 2 hours of the trip? f) Which line represents the fastest speed? f) Apply simple mathematic relationships to determine a missing quantity in a mathematic expression, given the two remaining terms (including speed = distance / time, density = mass / volume, force = pressure x area, volume = area x height) (Memorize these) S = D D = M F = P V = A x H or V = L x W x H T V A g) Distinguish between linear and nonlinear relationships on a graph of data. Linear is straight Nonlinear is not straight (may be curved or may not have a pattern)