SEMESTER 1 PHYSICAL SCIENCE FINAL STUDY GUIDE

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1 SEMESTER 1 PHYSICAL SCIENCE FINAL STUDY GUIDE Science Process Skills Know these vocabulary words and be able to use them to answer higher level questions about experiments and data collection: What do we study in physical science? Chemistry and Physics What is matter? The amount of mass that makes up an object What is energy? The ability to do work and cause change What is the Scientific Method? Scientists are filled with curiosity and ask many questions about our world and our universe. They use the problem solving process called the scientific method to investigate and find answers to their questions. What is an independent variable in an experiment? The variable in an experiment that is changed on purpose by the scientist. The factor that I (the scientist) choose to change or manipulate for an experiment. What is a dependent variable in an experiment? The variable that responds to changes in the independent variable in an experiment. The variable you will measure and collect data on during an experiment. What is a manipulated variable in an experiment? The Independent Variable What is a responding variable in an experiment? The Dependent Variable What are the constant conditions in an experiment? All the variables in an experiment that the scientist decides will remain exactly the same for the whole experiment. What is the Non-Treated/Control Group in an experiment? The item or group in an experiment that remains unchanged or does not include the independent variable. This group is used as comparison for checking the results of an experiment and gives you evidence to draw conclusions about your independent and dependent variables. What are qualitative observations? Observations made during an experiment that involve the senses (hearing, seeing, tasting, smelling, touching). These are descriptions of what we observe about the conditions in the experiment. What are quantitative observations? Observations made during an experiment that involve numbers or amounts. These are measurements of what we observe.

2 What is the hypothesis in an experiment? A statement that offers an answer to a testable question that has been asked. It is written in the form: If (the independent variable) is (increased, decreased, changed), then (the dependent variable) will (increase, decrease, change) because (use prior knowledge, observations, inferences). What is the conclusion in an experiment? You use data and evidence from an experiment and then you analyze the data and explain how this answers your original testable question. What is the difference between an observation and an inference? An observation is anything we become aware of through one or more of our senses. While an inference is an explanation based on your observations. Inferences are not about being correct or not. Inferences should be logical. Inferences can be changed when new observations are made. Inferences use observations and prior knowledge to explain what happened in the past. Why don t we have one single scientific method that every scientist must use each time an experiment is conducted? The names of the steps can vary but usually involve a problem, formulating a hypothesis, making observations, collecting and analyzing data, and logical reasoning for drawing conclusions. The scientific method is just a guideline that we use in science. The steps can be changed or adapted to meet your specific experiment or investigation. What are the steps of the scientific method we are using this year? Step 1-State the Problem: Ask a Testable Question How does...?, What does...?, Which...?, How can...?, What can...? Step 2-Collect Background Information: Research information that will help you answer the testable question. Use books, articles, the Internet, and your own experience. Has this been done before? Do you have background knowledge of the science topics? Step 3-Invent a Hypothesis: Propose an answer to the testable question based on the background information you collected. State the hypothesis as a cause-effect relationship. Put it in an If (independent variable), then (dependent variable) because... statement. Step 4-Experiment: Record materials and equipment used; Be sure to take safety into account; Record your procedure (step by step process); Record the variables(s) that are being measured, manipulated and controlled. Could someone else read and follow your procedure and repeat your experiment? Step 5-Note Data: Create data tables so collected data is organized and easy to read; Make graphs using the collected data; Independent variable on x-axis and dependent variable on y- axis ; Look for patterns and relationships between the variables

3 Step 6-Conclusion: State the purpose of the experiment; Summarize the data collected and include any trends or patterns you discovered; Report if the data supports, partially supports, or does not support your hypothesis; Think about what changes could be made if the experiment were conducted again. Step 7-Educate Others: Inform others of the results and conclusions so investigations can be repeated Explain what occurs in each step of the scientific method See answer in question above Be able to pick out the independent variable, dependent variable, constant conditions/constants, control group/non-treated group if given an experiment scenario Look over your Science Process Skills Test Why we do multiple trials for experiments? To make sure our experimental results were not flawed. Be able to analyze a data table and a graph to draw a conclusion about an experiment Look over your Science Process Skills Test and your data table and graphing notes Know your science safety rules Look over your Safety Test What is a scientific law? An explanation of what is observed in the natural world. A law describes a pattern seen in the natural world. A law can be used to predict what will happen in a given situation, but it will not explain why it happens. What is a scientific theory? A well-established explanation for how or why a phenomenon happens in our natural world. The explanation is based on large amounts of data and observations that are supported by experimental results that have been proven multiple times. Scientific theories can explain scientific laws. Motion-Speed, Velocity, and Acceleration What is the position of a person or object? Where an object is located What is motion? Motion is an object s change in position over time when compared with a reference point. An object is in motion if its distance from another object changes. What is a reference point? A reference point is an object that is used for comparison to determine if other objects are in motion. What is distance? The amount that an object is away from a reference point. (Include its units)

4 What is displacement? The amount that an object is away from a reference point including its units AND the direction away from the reference point. What is speed? Speed is a type of rate that gives the distance an object travels in a given time. It is how fast an object is moving. Speed = Distance Traveled Time to Travel Distance What is velocity? Velocity is how fast an object is traveling and the direction it is traveling. Velocity = Distance Traveled in a direction Time to Travel Distance How are speed and velocity different? Velocity is the speed of an object with its direction What is average speed and average velocity? Average speed is the overall distance an object travels divided by the total time it took to travel the distance because most moving objects do not move at a constant speed. Average velocity is the same as average speed but it includes the direction. Average Speed = Total Distance Total Time Average Velocity = Total Distance in a direction Total Time What is constant speed and constant velocity? Constant speed is the speed of an object when the speed is the same at every point of its motion. Ex. Using Cruise Control Constant velocity is when an object is traveling at a constant speed and there is no change in the direction of the motion. What is instantaneous speed? The rate an object is moving at a given instant in time. What is acceleration? The rate at which an object s velocity is changing. An acceleration of an object occurs if there is any change in velocity, either its speed or direction. Acceleration = Final Velocity-Initial Velocity = v f v i Time to Change Velocity t Be able to explain what type of acceleration is going on in a given situation: (1) Speeding Up-Increasing Speed which is called positive acceleration (2) Decreasing Speed which is called negative acceleration or deceleration (3) Change in Direction-Ex. Circular Motion Be able to read and analyze Distance vs Time and Speed vs Time Graphs Look at the questions on graphing on your Motion Test and at your Motion Graphs Note Packet What kind of motion graph represents the speed of an object? Distance vs Time Graphs

5 What kind of motion graph represents the acceleration of an object? Speed vs Time Graphs Know the equations for Speed, Velocity, Average Speed, Average Velocity, Acceleration See questions above Be able to use the correct units when solving any equation or word problem related to motion- Speed, Average Speed ex. m/s, mi/h, km/h Velocity, Average Velocity ex. m/s, mi/h, km/h + a direction Acceleration ex. m/s 2, mi/h 2, km/h/s + a direction Forces What is a force? A push or pull in a particular direction. What is a balanced force? Two or more forces are balanced if there effects cancel each other out and they do not cause a change in an object s motion (If the object is stopped, it remains stopped and if the object is already moving then it keeps moving at the same speed and in the same direction.) What is an unbalanced force? Two or more forces are unbalanced if there effects do not cancel each other out because one force is stronger than the other. Unbalanced forces do cause a change in an object s motion either speed and/or direction. What is the net force? The total of all the forces acting on an object. What is a spring scale used for? A spring scale is used to measure the force that a push or pull is exerting on an object. What is a newton (N)? The unit used to measure a force. It is equal to kg m/s 2. What is friction? Friction is a force that is caused by the surface roughness when 2 objects are in contact. Friction always acts in the direction opposite of the motion of the object and causes moving objects to slow down or stop. Is friction a force? Yes, friction is a force that opposes motion. What 2 factors determine the amount of friction between two objects? (1) Types of surfaces involved and (2) How hard the surfaces push together due to the force of each object How can friction be useful? Yes, whenever you need friction to make something happen. For instance, we would not able to walk or hold things or open doors, etc. without friction.

6 How can friction be harmful? Friction creates heat which can damage equipment. Friction causes wear to things like tires and brake pads on a car. Friction makes it difficult to move objects especially if you are trying to slide heavy objects. What are the 2 main types of friction? Define them. 1. Static Friction - Friction when a force is applied to an object, but it does not cause the object to move. The static friction balances with the force applied so the object does not move. Static friction disappears as soon as the object moves and it is immediately replaced by another kind of friction. 2.Kinetic Friction - Friction of moving surfaces What are the 3 types of kinetic friction? Define them. Sliding Friction - Friction when solid surfaces slide over one another. Produces heat when the two objects are rubbed together. Example Rub your hands together quickly, Rubbing sticks together to make a fire Rolling Friction - Friction when an object rolls over a surface. The force needed to overcome rolling friction is usually much less than that for sliding friction. Fluid Friction - Friction that occurs when an object moves through a fluid. Fluids include liquids and gases. The force needed to overcome fluid friction is less than that needed to overcome sliding friction. Example To prevent heat from building up in a car engine, oil is used to lubricate the parts of the car engine so that it runs smoothly. How can you change the strength of friction between two surfaces? 3 Ways of Reducing Friction (1) Decrease the surface area between the things that are rubbing together by making them smoother -Any extra lumps or bumps on an object increases its surface area so it increases its friction. If you sand the object to make it smoother this will decrease the friction. (2) Use something to make the surfaces more slippery -Applying things like water, oil, or grease to a surface will decrease the friction because they will fill in any tiny holes on the surface. (3) Switch from sliding friction to rolling friction 3 Ways of Increasing Friction Do the opposite of the 3 things above

7 What is air resistance? A type of fluid friction that slows down objects falling through the air or objects moving forward through air (like a car) In what direction does friction always work? Opposite the motion of an object What is gravity? Gravity is a type of force that pulls things together. It is a together force, not a down force. On the Earth, the force of gravity is everywhere towards Earth s center. Is gravity a force? Yes, gravity is a type of force that pulls objects toward the center of an object. What 2 factors determine the amount of gravity between two objects? (1) The mass of each object involved (2) The distance between the 2 objects What is the Universal Law of Gravitation? The law that says that the force of gravity acts between all objects in the universe. What is projectile motion? Projectile motion is the curved path followed by an object when it is thrown or propelled. It has 2 components (1) Horizontal Motion and (2) Vertical Motion but objects in projectile motion only accelerate downward or vertically so you always need to aim above a target if you want to hit it with an object that is thrown or propelled. What is mass? Mass is the amount of matter or material that makes up an object. What is weight? The force of attraction between an object and whatever planet it is on. Each planet has a unique amount of gravity and you use that to multiple by the mass of an amount to determine its weight. Weight is a force. How much is the acceleration due to gravity on Earth? 9.8 m/s 2 What is terminal velocity? Terminal velocity occurs for an object when the Force of Air Resistance =Force of Gravity. As an object speeds up the air resistance also increases until the 2 forces are equal and the object reaches its terminal velocity. If you have balanced forces on an object then it no longer accelerates. If an object is not accelerating it is still falling but the velocity and the direction are not changing. What is weightlessness? Weightlessness occurs when an object is in free fall and is experiencing less gravity. (It is not when there is no gravity.)

8 What kind of motion is involved when an object orbits? When an object is in orbit it experiences forward motion and free fall. For all the following ideas look over your old Forces Test Be able to describe a force by its direction and magnitude Be able to compare the effects of balanced and unbalanced forces on an object s motion Be able to explain that when forces are balanced then the objects must be at rest or their motion remains constant Be able to explain that a change in motion results from an unbalanced force acting on an object Be able to recognize that all objects in the universe has a gravitational force of attraction on every other object Be able to recognize that an object s weight is a measure of the gravitational force of a planet or moon acting on an object Be able to compare the amount of gravitational force acting between objects (which depends on their mass and the distance between them) Be able to compare and contrast mass and weight Be able to determine which dropped objects will hit the ground first NEWTON S LAWS OF MOTION What are Newton s Three Laws of Motion? Newton s First Law of Motion: An object at rest will remain at rest, or an object moving at a constant speed will continue moving at that speed, unless acted upon by an unbalanced force. Newton s Second Law of Motion: The amount that an object will be affected by a push or a pull is equal to the mass of the object multiplied by the acceleration. Newton s Third Law of Motion: For every action, there is an equal and opposite reaction. Therefore, if one object exerts a force on a 2nd object, then the 2nd object exerts a force of equal strength in the opposite direction of the force back on the 1st object. What is inertia? Inertia is the tendency of anything with mass to resist a change in motion. The greater the mass of an object, the greater its inertia. How is the inertia of an object related to the mass of the object? The mass of an object determines its inertia. The greater the mass of an object, then the greater the inertia. What is the equation for Newton s 2 nd Law of Motion? Force = mass acceleration (F = m a) What is unit does this represent kg m/s 2? A newton (N)

9 What is an action force? The initial force from Object #1 onto Object #2. What is a reaction force? The second force that goes from Object #2 onto Object #1. What is momentum? Momentum is mass in motion so any moving object with mass has momentum. Momentum depends on (1) how much stuff is moving and (2) how fast that stuff is moving. What is the equation for momentum? Momentum (P) = mass velocity = m v What is the unit used of momentum? kg m/s What is the Law of Conservation of Momentum? The Law that says that momentum cannot be created or destroyed. How is the Law of Conservation of Momentum used to predict what happens in collisions? When an object with momentum collides with another object, the momentum is transferred. The total amount of momentum between two objects will add up to the same amount when you add the momentum of each one together before the collision and after the collision. For all the following ideas look over your old Newton s Laws section of your Forces Test Be able to explain how Newton s Laws of Motion apply to new situations Be able to predict how Newton s Laws affect moving objects Be able to solve word problems for Newton s 2 nd Law of Motion Be able to solve word problems for Momentum ENERGY What is kinetic energy? Energy of Motion that depends on both the mass of the object and its velocity What is potential energy? Stored energy What is gravitational potential energy? Stored energy due to the position (where it is located) of an object

10 What is elastic potential energy? Stored energy in the stretch of an object Ex. Rubber Band or Slinky How are kinetic and potential energy related? Kinetic and potential will always equal the total energy of a system. The mechanical energy or total energy of an object due to its motion and its stored energy. How do you calculate kinetic energy? KE = mass velocity 2 or m v How do you calculate potential energy? PE (or GPE) = Weight Height (W h) or = mass gravity height (m g h) Remember that g = 9.8 m/s 2 Can kinetic energy and potential energy be converted to one another? How do you know? Yes because the total energy of the system must always it up to the same amount so when potential energy goes up kinetic energy goes down and vice versa. How do you calculate total mechanical energy? Mechanical Energy = Potential Energy + Kinetic Energy ME = PE + KE How are energy and work related? Energy is the ability to do work or cause change. An object with energy can change itself or cause change in other objects. What are the units for energy? Joule (J) = N m = kg m 2 /s 2 What is the Law of Conservation of Energy? Energy can never be lost, can never be created, and can never be destroyed so energy can only change from one form to another form. Can energy change from 1 form to another while the total energy remains the same? Yes because this is the Law of Conservation of Energy. Can energy be created or destroyed? Never ENERGY CONVERSIONS What is mechanical energy? All the energy in a system but it is often used to describe just the kinetic energy. What is thermal energy? It is also known as heat energy. Thermal Energy is a form of Kinetic Energy. The faster the particles move, the more heat energy they have. What is chemical energy? Energy that exists in the bonds between atoms and is released when the bonds are broken. Chemical Energy is a form of Potential Energy.

11 What is radiant energy? Radiant energy is Electromagnetic Energy traveling in transverse waves. It can travel through a vacuum where there are no molecules. It includes different forms of energy but we used it to refer to light energy. It is a form of Kinetic Energy. What is sound energy? Sound is produced when a force causes an object or substance to vibrate the energy is transferred through the substance in a wave. Typically, the energy in sound is far less than other forms of energy. Sound Energy is a form of Kinetic Energy. What is electrical energy? It is the movement of electrons. Electrical energy is an example of Kinetic Energy. What is nuclear energy? The energy stored in the nucleus of an atom that is usually used for holding protons and neutrons in the nucleus. Nuclear Energy is a form of Potential Energy. The heat and light from the Sun is a form of nuclear energy. How are each of these forms of energy related to kinetic and potential energy? See my answers above Be able to explain how potential and kinetic energy change (think roller coaster lab and Energy Skatepark) Be able to able to identify which forms of energy are being transformed in different situations Look at your practice sheets Be able to explain how thermal energy is always a result of an energy conversion Due to friction Be able to explain why perpetual motion is impossible Due to friction there is not a machine that is able to go on and on forever without adding more energy to it. WORK AND POWER What is work? Work is done when a force transfers energy to an object to make it move a certain distance in the same direction as the force. When is work done on an object? When there is a force on an object and the object moves in the direction of that force. What is the unit used when measuring work? A Joule (J) What is a joule (J) equal to? Joule (J) = N m = kg m 2 /s 2 What is power? The rate at which work is done or the amount of time it takes to get work done.

12 What is a rate? A rate is when an amount of one thing is related to an amount of another thing. In science we usually use rate to show how doing something is related to the amount of time it takes to do it. What is the rate at which work is done? Power What is the unit used when measuring power? Watt (W) What is a watt (W) equal to? 1 W = 1 J/s Look at your 4 readings and your practice sheets: Be able to recognize examples of when work is and is not being done on an object Be able to calculate the amount of work done on an object Be able to calculate the amount of power of an object Be able to explain the difference between work and power Be able to apply the ALL vocabulary if given a new situation or scenario Be able to answer any application questions about any concept we have studied