8 th Grade Physical Science

Transcription

1 Everything you need to know about: 8 th Grade Physical Science Directions: Answer ALL the questions for each unit, in preparation for the SOL! Each answer must be handwritten, answered completely on your own paper, grouped by unit, and numbered. DON T define the key terms. This is a summative grade out of 40 points! Unit 1 Measurement & Safety Key terms: physical science, Newton (N), volume, density, meniscus, cubic centimeter (cm 3 ), liter, water displacement method, weight, metric conversion 1. List five safety procedures for the lab. * Wear safety goggles, apron, gloves, closed-toed shoes, etc. * Waft, never smell directly * Always add acids to water or other chemicals * No food, drink, gum, or tasting of materials in the lab * Tell a teacher if glass or other equipment breaks 2. Why do we use the metric system in science? It is the internationally accepted system of measurement by all scientists/ easy to convert, based on a unit of Convert 200cm to meters. 2m 4. a. How would you measure and calculate the density of a silver bracelet? Find its mass using a triple beam balance and its volume by dropping it into a graduated cylinder filled with water. Calculate the density by dividing the mass by the volume. D = m/v b. How could you check to see if the bracelet truly was silver? Compare it to the density of silver or use other physical and chemical properties. Unit 2 Describing Matter Key terms: Matter, Physical property, Chemical property, physical change, chemical change, solubility, element, compound, mixture, homogeneous, metal, nonmetal, metalloid, solid, liquid, gas, organic compound, heterogeneous, malleability, ductility, luster, reactivity, combustibility, precipitate, Law of Conservation of Mass 1. Give 2 examples of physical properties. Color, size, shape, state of matter, solubility, lustre, malleability, ductility 2. Give 2 examples of chemical properties. Reactivity, flammability, ph, combustibility 3. Is there a change in identity when observing physical changes? No, physical changes don t change the identity of the substance. Example: If I cut my hair, it s still hair, just a different shape/size. 4. Give an example of a physical change. Crumpling up my paper, melting chocolate 5. Give an example of a chemical change. Burning, exploding, rusting, souring, rotting

2 6. What are the four signs that a chemical change is taking place? Unexpected color change Gas released Precipitate forms Production of light, heat, sound, or odor 7. How are elements, compounds, and mixtures different? Elements are on the Periodic Table, made up of one substance. Compounds are substances that are chemically combined and separated. Mixtures are substances that are physically combined and separated. Unit 3a Chemistry (Part One) Key terms: proton, neutron, electron, atomic number, atomic mass, isotope, Dalton, Thomson, Rutherford, Bohr, Schrodinger and Heisenberg, Atom, Atomic mass unit (amu), atomic symbol, Valence electrons, period, group, family 1. Briefly list the contributions of Dalton, Thomson, Rutherford, and Bohr in constructing the modern model of the atom. Dalton- All substances are made of atoms. Atoms of the same element are exactly alike; atoms of different elements are different. Thought an atom looked like a solid round ball. Thomson Discovered the electron. Thought an atom looked like plum pudding with the pudding being the positively charged goo and the electrons were like plums scattered around in the pudding. Rutherford- Through his gold foil experiment, discovered that most of the mass was in the nucleus and the rest of the atom is mostly empty space with electrons around the nucleus somewhere. Bohr The Bohr Model has the protons and neutrons in the nucleus and the electrons on rings (definite paths) around the nucleus. 2. Calculate the number of protons, neutrons, and electrons for carbon-12. Carbon-12 = 6 Protons, 6 electrons, 6 neutrons 3. What is the mass of a proton, neutron, and electron? Proton: 1 amu. Neutron: 1 amu. Electron: about 0 amu. 4. How do you find the atomic number and atomic mass of an element? Look at the periodic table. The atomic number is the smaller number at the top, and tells you the number of protons in the atom. The atomic mass is the larger number at the bottom, and tells you the average atomic mass (protons + neutrons) of the element. 5. What do the period and the group of an element tell you? Periods are the rows going across (horizontally). There are 7 periods. Periods follow a pattern with the left side being very reactive metals, the middle only a little reactive, the right side being very reactive nonmetals, and the very last element in the period inert (nonreactive). Groups are the columns going up/down. Because elements in the same group share the same number of valence electrons, they share similar properties. 6. Name the eight families of the periodic table. Alkali metals (group 1) Very reactive metals, never found uncombined in nature, 1 valence electron. Alkaline earth metals (group 2) Also very reactive metals, but slightly less so than group 1. Never found uncombined in nature, have 2 valence electrons. Transition metals (groups 3-12) Somewhat reactive, properties and valence electrons vary. BCNO family (groups 13-16) The only family that contains metalloids; also nonmetals and metals. Reactive. Have 3-6 valence electrons. Halogens (group 17) Very reactive nonmetals, never found uncombined in nature. Have 7 valence electrons and react violently with alkali metals. Noble gases (group 18) These gases have 8 valence electrons, so they are inert (unreactive). All are found in the Earth s atmosphere in small amounts.

3 Lanthanides the first of the two rows at the bottom of the periodic table, they are actually transition metals who simply didn t fit because the periodic table would be too wide. They come after Lanthanum in the periodic table. They are shiny, reactive metals. Actinides Also found at the bottom of the periodic table, they are transition metals following the element Actinium. All are reactive and radioactive. Unit 3b Chemistry (Part Two) Key terms: ion, reactants, products, Covalent, Ionic, Acid, Base, ph, neutralization 1. Which class of elements tend to lose electrons? metals 2. List the elements that are inert. Helium, neon, argon, krypton, xenon, radon 3. Compare and contrast ionic and covalent bonding. Ionic bonding is when atoms gain or lose electrons to become ions and the charged ions become attracted to each other forming a bond. Nonmetals tend to steal electrons and become negatively charged ions, while metals tend to ditch electrons and become positive ions. Covalent bonding is when atoms share electron pairs to form bonds. These bonds typically form between nonmetals. 4. Balance the following equation: Na + H2O NaOH + H2 2 Na + 2 H2O 2 NaOH + H2 5. Circle the acids. Underline the bases. Coffee: ph 5/ Coca Cola: ph 4/ Baking Soda: ph 9/ Tide laundry soap: ph 11.5/ Pure Water: ph 7/ Fluids of the stomach: ph 1 Unit 4 Heat Key terms: temperature, heat, thermal energy, conduction, convection, radiation, absolute zero, conductor, insulator, thermal expansion, Joule, heat engine, solid, refrigeration, heat pump, thermostat, heat engine, liquid, gas, plasma, endothermic, exothermic, freezing, melting, condensation, evaporation, deposition, sublimation, vaporization 1. What are the three temperature scales? Fahrenheit, Celsius, Kelvin 2. How is Kelvin different from the other scales? Kelvin starts at the lowest possible temperature- absolute zero so it has no negative numbers. 3. What is thermal expansion? The tendency for matter to expand when you increase its temperature. 4. How are heat and thermal energy related? Thermal energy is the total kinetic energy of the particles, and heat is the transfer of that energy from the warmer object to the cooler object. 5. Name the three types of heat energy transfer and give an example of each. Conduction- by direct contact (touching). Example: burn your hand touching a hot stove. Convection movement in a liquid or gas as the hot rises and cold sinks. Example: convection currents in your house cause you attic to be hotter than your basement. Radiation transfers thermal energy through space as electromagnetic waves. Example- I feel warm when I stand outside on a sunny day because of solar radiation. 5. Give an example of a material that is a conductor and a material that is an insulator. Conductor any metal. Insulator- rubber. 6. Name the three states of matter and describe the particle movement of each.

4 Solid the particles vibrate in place Liquid particles can move a little more, sliding past each other Gas the particles break free of one another, moving around quickly, expanding to fill their container. 6. Draw the phase change triangle and label it. Unit 5 Electricity & Magnetism Key terms: electricity, series circuit, alternating current (AC), parallel circuit, direct current (DC), magnet, static electricity, poles, conduction, magnetic force, induction, electromagnetic induction, conductor, electromagnet, insulator, solenoid, semiconductor, turbine, diode, generator, transistor, electric motor, circuit, transformer, circuit board, light-emitting diode (LED), integrated circuit board, solar cell 1. What is the relationship between resistance and current (Ohm s Law)? The greater the resistance, the lower the current and vice versa. I = V/R (Ohm's Law) 2. How can you increase the strength of an electromagnet (3 ways)? Add coils/ Add current/ increase size of iron core 3. Draw a series circuit and a parallel circuit with a switch each that turns off all the lights. SERIES 4. What does the Law of Electrical Charges state? Like charges attract and opposite charges repel each other. 5. Name three ways that objects can be charged and explain each. Friction rubbing two objects together to shed the electrons from one onto the other Conduction transfer of electric charges by direct contact

5 Induction transfer of electric charges by indirect contact; when a charged object approaches an uncharged object forcing the charges away from the surface and temporarily charging the second object with the opposite charge. 6. What are four ways to reduce resistance? Thicker wires/ Shorter wires/ Cooler/lower temperatures/ Better conductor material (ex. Copper is better than iron) 7. When is a material considered to be magnetic? It must contain or be attracted to iron. 8. What is electromagnetic induction? The process of changing a magnetic field to generate an electric current. 9. What is the difference between a generator and a motor? Provide examples of each. Generators use electromagnetic induction to convert kinetic energy into electrical energy. Examples of generators include: hand-crank flashlights, wind turbines, or home generators. Electric motors convert electrical into kinetic energy. Ex. blender, toaster, hair dryer, fan, etc. Unit 6 Waves (Part One) Key terms: wave, scientific notation, medium, absorption, transverse wave, scattering, longitudinal wave, transparent, crest, translucent, trough, opaque, amplitude, resonance, wavelength, concave, compression, convex, rarefaction, convergence, mechanical wave, divergence, electromagnetic wave, mirror, frequency, lens, pitch, electromagnetic spectrum, loudness, radio waves, Doppler effect, microwaves, sonar, ultrasound, infrared waves, visible light, echolocation, ultraviolet light, reflection, X-ray, refraction, gamma rays, diffraction, constructive interference, destructive interference 1. a. Draw a transverse wave and label amplitude, wavelength, crest, and trough? b. State whether it is mechanical or electromagnetic and what state of matter it can travel the fastest through? This is an electromagnetic wave (e.g. light wave). Light waves travel the fastest through a vacuum (or a gas medium). 2. a. Draw a longitudinal wave and label compressions, rarefactions, and wavelength? b. State whether it is mechanical or electromagnetic and what state of matter it can travel the fastest through? This is a mechanical wave (e.g. sound wave). Sound waves travel the fastest through a solid. In a solid particles are closer together allowing energy to be transferred faster through vibrations.

6 3. Draw a diagram of refraction and label the different media that they are traveling through. air water 4. Draw a diagram for diffraction. 5. Describe how the speed of sound changes in different media and temperatures? Sound travels fastest in solids where the particles are close together and the vibrations can easily transfer from one to another. Similarly, sound travels fastest in warmer temperatures as the particles are already moving quickly which passes the vibrations along more quickly. 6. Discuss the relationship between frequency and wavelength? They are inversely related, meaning that as one increases, the other decreases. 7. How do you calculate wave speed? Wave speed = wavelength x frequency OR ⱱ = ƛ. f 8. Identify the law of reflection? The angle of incidence is equal to the angle of reflection. 9. Describe the difference between mirrors and lenses? Mirrors are reflective surfaces that allow light to reflect back at us. Lenses allow light to pass through. 10. Draw a concave lens and a convex lens. 11. Explain the difference between transparent, translucent, and opaque. Transparent - allows light to pass through; see through. Translucent - allows some light to pass through; cannot not fully see through but can make out shapes on other side. Opaque - does not allow light to pass through; cannot see through 12. Describe what makes waves different on the electromagnetic spectrum? Waves vary by wavelength, frequency and energy. The longer the wavelength, the lower the frequency and energy. 13. Name the characteristics of the seven types of waves in the electromagnetic spectrum. Radiowaves -longest wavelength, lowest energy, send signals to radio towers Microwaves -transfers energy to water molecules in foods to heat up the food Infrared waves -used for thermal imaging e.g. night vision goggles Visible spectrum -only part of the light spectrum we can see: ROY G. BIV Ultraviolet waves -harmful to our skin, causes sun burn

7 X Ray waves -used to produce images of bones Gamma ray waves -shortest wavelength, highest energy, used to treat cancer Unit 7 Force & Motion Key terms: speed, Distance, velocity, Resultant velocity, acceleration, Displacement, Newton s 1 st, Law, force, Motion, Net force, newton, Inertia, Momentum, Friction, Newton s 2nd Law, Newton s 3rd Law, work, joule, gravity, Law of Universal Gravitation, power, watt, pulley, Machine, Inclined plane, Mechanical advantage, Input force, Output force, Mechanical efficiency, Lever, fulcrum, screw, Wheel and axle, Compound machine 1. Give examples of each of Newton s three laws of motion. a) Newton s 1 st law: An object at rest remains at rest and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force. Example- a golf ball will remain at rest on its tee until it is acted on by the unbalanced force of your moving golf club. b) Newton s 2 nd law: The acceleration of an object depends on the mass of the object and the amount of force applied. Example- It s easier to accelerate an empty shopping cart when you push it than it is to accelerate a full shopping cart. c) Newton s 3 rd law: Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first. Example- When you hit a baseball with your bat, your bat exerts a force on the ball to send it flying away through the air, but the ball also exerts an equal force on the bat. This is why your hands hurt after you hit something with a bat. 2. Describe the difference between speed, velocity, and acceleration. Velocity is like speed except that velocity is speed in a given direction. For example, speed of a moving car is 40 miles per hour. Velocity would be 40 mph north. Acceleration is the rate at which velocity changes. 3. Describe how you would decrease friction. Use a lubricant, put it on wheels (or ball bearings), make the surfaces that rub against each other smoother. 4. Draw what a distance-time graph looks like if you were stopped and not moving. 5. Describe how you would increase gravity. Increase the mass of the objects or decrease the distance between them 6. Describe why we do not have a 100% efficient machine. Some of the force is always used to overcome friction 7. Detail why mechanical advantage is useful. Simply, it tells you how many times better than you the machine is. More scientifically, mechanical advantage is the difference between the input and output force. Machines increase the amount of output force for greater mechanical advantage. 8. Contrast how work and power are different. Work is done on an object when a force makes the object move in the direction of the force. Power is the rate at which work is done.

8 9. Contrast the difference between distance and displacement. Distance is how far you have traveled and displacement is how far you are from where you started. 10. Name the six simple machines. Inclined plane, wheel & axle, wedge, lever, screw, pulley Unit 8 Energy Key terms: Energy, potential energy, kinetic energy, mechanical energy, radiant/electromagnetic energy. thermal energy, chemical energy, electrical energy, nuclear energy, Energy transformation, nuclear fusion, nuclear fission, Law of Conservation of Energy, Renewable Resources, Nonrenewable Resources, fossil fuel, biomass, solar, geothermal, hydroelectric 1. Name two non-food examples of chemical energy? firewood (burning it releases the chemical energy), gasoline, batteries, etc. 2. Label the diagram below with the bulleted points: KE is the most PE is the greatest PE is turning into KE KE is turning into PE 3. Draw nuclear fission and nuclear fusion? 4. Define renewable and nonrenewable resources and say why it is important to use both Renewable resources are necessary for our future, because they are typically kinder to the environment and are readily available. Nonrenewable energy sources are our greatest source of energy and can produce more energy for us to use faster today.

9 Below you will find a list of dates to help keep you on track with submitting each unit. You may turn in ANY UNIT at ANY TIME as long as all nine sections are completed by the final due date: 5/19/2017. Keep track of the units you turn in by checking them off as you go! Unit 1 Unit 2 Unit 3a Unit 3b Unit 4 Unit 5 Unit 6 Unit 7 Unit 8 4/28 4/28 5/5 5/5 5/5 5/12 5/12 5/19 5/19