Physical Science NAME: PERIOD:________EOCT Study Guide 2012

Semester 1

SPS8. Students will determine relationships among force, mass, and motion. a. Calculate velocity and acceleration. b. Apply Newton’s three laws to everyday situations by explaining the following: Inertia; Relationship between force, mass and acceleration; Equal and opposite forces c. Relate falling objects to gravitational force d. Explain the difference in mass and weight. e. Calculate amounts of work and mechanical advantage using simple machines.

SPS7. Students will relate transformations and flow of energy within a system. a. Identify energy transformations within a system (e.g. lighting of a match). b. Investigate molecular motion as it relates to thermal energy changes in terms of conduction, convection, and radiation. c. Determine the heat capacity of a substance using mass, specific heat, and temperature. d. Explain the flow of energy in phase changes through the use of a phase diagram.

SPS9. Students will investigate the properties of waves. a. Recognize that all waves transfer energy. b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and mechanical waves. c. Compare and contrast the characteristics of electromagnetic and mechanical (sound) waves. d. Investigate the phenomena of reflection, refraction, interference, and diffraction. e. Relate the speed of sound to different mediums. f. Explain the Doppler Effect in terms of everyday interactions.

SPS2. Students will explore the nature of matter, its classifications, and its system for naming types of matter.

a. Calculate density when given a means to determine a substance’s mass and volume.

SPS3. Students will distinguish the characteristics and components of radioactivity. a. Differentiate among alpha and beta particles and gamma radiation. b. Differentiate between fission and fusion. c. Explain the process half-life as related to radioactive decay. d. Describe nuclear energy, its practical application as an alternative energy source, and its potential problems.

SPS5. Students will compare and contrast the phases of matter as they relate to atomic and molecular motion.

a. Compare and contrast the atomic/molecular motion of solids, liquids, gases and plasmas. b. Relate temperature, pressure, and volume of gases to the behavior of gases.

SPS1. Students will investigate our current understanding of the atom.

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a. Examine the structure of the atom in terms of: proton, electron, and neutron locations; atomic mass and atomic number; atoms with different numbers of neutrons (isotopes); explain the relationship of the proton number to the element’s identity. b. Compare and contrast ionic and covalent bonds in terms of electron movement.

SPS4. Students will investigate the arrangement of the Periodic Table. a. Determine the trends of the following: Number of valence electrons; Types of ions formed by representative elements; Location of metals, nonmetals, and metalloids; Phases at room temperature b. Use the Periodic Table to predict the above properties for representative elements.

NOTES

SPS8: Students will determine relationships among force, mass, and motion.a. Calculate velocity and acceleration.

Velocity is speed in a given direction (v measured in m/s) 1. speed in a particular direction

2. formula: velocity = displacement (distance and direction)/Time

Sample Problem: What is the average velocity of a commercial jet that travels west from New York to Los Angeles (4800 km) in 6.00 hours?

Velocity = distance/ time

Velocity = 4800 km/6.00 hours

Velocity = 800 km/hr west

Acceleration is the rate of change in velocity (a measured in m/s2) 1. the rate at which velocity changes

2. formula: acceleration = final velocity-initial velocity/time

or acceleration = (a=

V−V 0

t )3. Acceleration occurs if either of these two conditions exist.

a. The speed of an object is changing. It can be increasing or decreasing.

b. The direction of the movement is changing.

Sample Problem: If a car accelerates from 5 m/s to 15 m/s in 2 seconds, what is the car's average acceleration?

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V = 15 m/s(a=

V−V 0

t ) Vo = 5 m/s a= 15 m/s - 5 m/s = 10 m/s = 5 m/s2

t = 2 sec 2 sec 2 s

SPS8: Students will determine relationships among force, mass, and motion.b. Apply Newton’s three laws to everyday situations by explaining the following: Inertia; Relationship between force, mass and acceleration; Equal and opposite forces

Newton's Laws of Motion are three laws which describe the relationship between forces acting on an object and the motion of that object.

1. An object that is at rest or in uniform motion tends to stay at rest or in uniform motion, respectively, until acted upon by an outside force.2. The net force on an object is equal to the mass of the object multiplied by the acceleration of the object.3. For every action, there is an equal and opposite reaction.

But what exactly is meant by the phrase unbalanced force? What is an unbalanced force? In pursuit of an answer, we will first consider a physics book at rest on a tabletop. There are two forces acting upon the book. One force - the Earth's gravitational pull - exerts a downward force. The other force - the push of the table on the book (sometimes referred to as a normal force) - pushes upward on the book.

Since these two forces are of equal magnitude and in opposite directions, they balance each other. The book is said to be at equilibrium. There is no unbalanced force acting upon the book and thus the book maintains its state of motion. When all the forces acting upon an object balance each other, the object will be at equilibrium; it will not accelerate.

A book sliding to the right across a tabletop (the forces acting upon the book are shown below).The force of gravity pulling downward and the force of the table pushing upwards on the book are of equal magnitude and opposite directions. These two forces balance each other. Yet there is no force present to balance the force of friction. As the book moves to the right, friction acts to the left to slow the book down. There is an unbalanced force; and as such, the book changes its state of motion. The book is not at equilibrium and subsequently accelerates.

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A. Newton’s Laws of Motion1. The Law of Inertia or Newton’s First Law: An object at rest tends to stay at rest and an object in motion tends to remain in motion in a straight-line path unless acted on by an unbalanced force.

a. Inertia is the resistance of any physical object to a change in its state of motion or rest.b. Applications:

i. This activity is similar to the magician's trick of pulling a tablecloth out from under dishes on a table. Because the dishes have inertia, they will stay at rest unless acted on by some unbalanced force. If the tablecloth is really smooth and is pulled out fast enough, there is not enough friction created to cause the dishes to move. DO NOT TRY THIS AT HOME WITHOUT PARENT PERMISSION!

ii. People are often thrown from automobiles in wrecks because the car comes to a sudden stop, but the person has a tendency to stay in motion.

iii. The ride is much smoother on a cruise ship than a fishing boat, because the cruise ship is more massive and is not affected as much by the waves.

2. Newton’s Second Law: The acceleration of an object is directly proportional to the applied force and inversely proportional to its mass.

F=ma F= force measured in Newton; m = mass in kg; a = acceleration in m/s2

This law also means that force is directly proportional to acceleration and mass. Thus, if the force placed on an object is doubled, the acceleration of the object will also be doubled. In addition, the mass of the object and the acceleration of the object are inversely proportional. If the mass of an object is halved, the acceleration on the object is doubled (when the force remains the same).

An example of this law would be if a bowling ball and a soccer ball were dropped from the same height at the same time. Gravity accelerates the objects at the same speed (as it does for all objects), so the difference in forces as the balls hit the ground would be due to the mass of the ball. Thus, the bowling ball, which has the larger mass, would hit the ground with a greater force.

Sample Problem: What is the force exerted by a 2 kg mass that accelerates at 3 m/sec/sec?

m = Mass = 2 kg F=ma a = acceleration = 3 m/sec/sec F =2 kg x 3 m/sec/sec = 6 N = 6 kg.m/sec/sec

(1 newton = 1 kilogrammeter/second/second)3. Newton’s Third Law: For every action there is an equal and opposite reaction.

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In other words, whenever object A exerts a force on object B, object B exerts an equal force (in the opposite direction) on object A. Both forces are exerted along the same line.

For example, when a bird flies, its wings push downward on the air. The air then pushes upward on the wings (and the bird). The action of the bird flapping its wings (exerting a force on the air) helps the bird fly (the air exerting a force on the bird).

a. If object A exerts a force on object B, then object B exerts an equal force on object A in the opposite direction.

b. Consequences: Forces always exist in pairs. It is impossible for you to push on something without it pushing back. Newton’s Third law can be used to explain the motion of rockets and balloons. As the gases exit the balloon or rocket, they push it in the opposite direction.

Motion depends on the observer’s frame of reference

SPS8. Students will determine relationships among force, mass, and motion.c. Relate falling objects to gravitational force

In the late 1600's, Sir Isaac Newton developed the law of universal gravitation. According to this law, every object exerts gravitational force on every other object. The amount of gravitational force that an object is able to exert depends on:

•the object's mass and the distance between the objects

So, in the example of the falling apple, since the Earth has much more mass than the apple, the apple is pulled toward the Earth more than the Earth is pulled toward the apple. The net unbalanced force points in the direction of the Earth.

Gravitational force also depends on the distance between two objects. In fact, differences in distance have a greater effect on gravity than do differences in mass. For example, the gravitational force between the Earth and the Sun is stronger than the force between Jupiter and the Sun. Even though Jupiter has a greater mass than the Earth, the shorter distance between the Sun and the Earth makes the force between the Sun and the Earth much stronger than the force between the Sun and Jupiter.

The value of a gravitational force can be calculated using the law of universal gravitation in its mathematical form, shown below.

In the equation, F is the force of gravity, G is the universal gravitational constant, m1 and m2 are the masses of the two objects, and d is the distance between them. SPS8. Students will determine relationships among force, mass, and motion.

d. Explain the difference in mass and weight. Mass is defined as the amount of matter an object has. Weight is defined as the force of gravity on a mass.

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A spring scale can be used to measure weight. Mass is the same on the Moon as it is on Earth, but the weight of an object is 1/6 as much on the Moon as on the Earth.The weight of an object is the force of gravity on the mass:

F = mg or F =W = mg, where ‘g’ is acceleration due to gravity (g=9.81 m/s/s)

Where:•F is the force of gravity on the mass in newtons (N) or pounds (lbs)•m is the mass of the object in kg or pound-mass•g is the acceleration due to gravity (9.8 m/s2 or 32 ft/s2)•W is the weight in N or lbs

SPS8. Students will determine relationships among force, mass, and motion.

e. Calculate amounts of work and mechanical advantage using simple machines

WORKWork is force exerted on an object that causes the object to move some distance

Force without moving a distance yields NO WORK!!. Work can be defined by the following equation:

W = F x d

Joule = Newton x Meter

where . . . F = the force applied to an object and d = the distance the object moves in the direction of the force. Simple MachinesA machine is a device that makes work easier or more effective.A machine makes work easier by changing the amount of force, the distance covered or by changing the direction of the forceThere are six simple machines: •the inclined plane

A plane is a flat surface. When that plane is inclined, or slanted, it can help you move objects across distances. And, that's work! A common inclined plane is a ramp. Lifting a heavy box onto a loading dock is much easier if you slide the box up a ramp--a simple machine.

•the wedgeWhen you can use the edge of an inclined plane to push things apart or when the incline plane can be

moved then, the inclined plane is a wedge. So, a wedge is actually a kind of inclined plane. An axe blade is a wedge. Think of the edge of the blade. It's the edge of a smooth slanted surface.

•the screwan inclined plane wrapped around a cylinder. A screw can convert a rotational force (torque) to a linear

force and vice versa.

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•the leverA lever is a rigid bar that "pivots" (or turns) against a "fulcrum" (or a fixed point).

There are three classes of levers:1. First Class Lever: The input & output forces are in opposite directions. The fulcrum is between the

input & output forces. Examples include: nail remover, paint can opener scissors, seesaw.

2. Second Class Lever: The input & output forces are in the same direction. Input force is farther away from the fulcrum than the output force. Examples include: wheel barrow, door, nutcracker.

3. Third Class Lever: The input & output forces are in the same direction. The input force is closer to the fulcrum than the output force. Examples include: rake, shovel, baseball bat and fishing pole.

•the pulleyIn a pulley, a cord wraps around a wheel. As the wheel rotates, the cord moves in either direction. Now,

attach a hook to the cord, and you can use the wheel's rotation to raise and lower objects.

•the wheel and axleIt includes two circular objects attached together about a common axis. Wheel is the large cylinder.

Axle is the small cylinder

The inclined plane, the wedge, and the screw all make work easier by requiring a smaller force to be applied through a longer distance. For example, it requires more force to pick a box straight up than it does to push it up a ramp, but the box travels a greater distance up a ramp than it would if it were simply picked up.

The lever, the pulley, and the wheel and axle make work easier by changing the direction of the applied force. For example, instead of having to pull a bucket of water up out of a well, a rope can be attached to the bucket and wrapped around a pulley. The pulley makes work easier because it lifts the bucket up by allowing the rope to be pulled down.

EfficiencyThe efficiency of a machine compares the work output to the work input. The formula for efficiency is: efficiency = (work output/work input) x 100%

The work done by the machine is called the work output. The work output is equal to the force applied by the machine multiplied by the distance through which the force is applied.

The work done on the machine is called the work input. The work input is equal to the force applied on the machine multiplied by the distance through which the machine moves.

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For example, if you pull down on the handle of a shovel to lift a pile of dirt, the work input is equal to the force that you applied to the handle times the distance that the handle moved. The work output is equal to the force the shovel exerted on the dirt times the distance the dirt moved.

Although machines make work easier, they do not multiply work; that is, the work output can never be greater than the work input, and the efficiency of a machine can never be greater than 100%.

Mechanical AdvantageThere are two forces involved when using machines...•the effort force (FE) is the force that is applied to the machine•the resistance force (FR) is the force applied by the machine

The mechanical advantage of a machine is the number of times the machine multiplies the effort force.

In general, it is calculated using the formula... MA = FR / FE or MA

Mechanical advantage involving distance:A machine has distance mechanical advantage when the output distance is greater than the applied distance.

There are times when you want to apply a force a short distance to increase the distance an object moves. One good example is when you peddle a bicycle. The distance you move the peddles on a bicycle are much less than the distance moved on the circumference of the tires.The bicycle and other machines may provide a distance mechanical advantage. The equation for this is:

MAd = dL/dE where, •MA d is the distance mechanical advantage•dL is the distance the load moves or the output distance•dE is the distance the effort moves or the input distance

Alternately, the mechanical advantage of each of the six simple machines can be determined using the following information:•inclined plane - the mechanical advantage equals the length of the plane divided by the height of the plane•wedge - the mechanical advantage equals the length of the sloping side of the wedge divided by the width of the thick end of the wedge•screw - the closer the threads are, the greater the mechanical advantage•lever - the mechanical advantage equals the length of the effort arm divided by the length of the resistance arm•pulley - the mechanical advantage equals the number of rope segments that directly support the object being moved•wheel and axle - the mechanical advantage equals the radius of the wheel divided by the radius of the axle

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SPS7. Students will relate transformations and flow of energy within a system. a. Identify energy transformations within a system (e.g. lighting of a match). Energy is the ability to do work.

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There are two types of energy:Kinetic Energy: the energy of motionPotential Energy: stored energy

Potential Energy can be changed into Kinetic Energy. Also Kinetic Energy can be changed into Potential Energy

Energy can take several different forms, including: •mechanical energy•electrical energy•heat energy•light energy•sound energy•chemical energy

1. Mechanical energy is the energy that an object has due to its motion or its position. It can be further classified as kinetic energy, or energy of motion, and potential energy, or stored energy of position. Mechanical energy is present in:

•a moving car•a book on a desk•a ball that is thrown

2. Electrical energy moves charged particles from one place to another. When a conductor—something that electrons can move through—makes a path from one end of a battery to the other or one side of an outlet to another, electrons begin flowing through it, creating electricity. The path along which they flow is a circuit. These moving electrons flow through wires as a current, or a continuous flow of electrically charged particles. These currents can do work, converting their electrical energy to another type of energy (e.g., heat, light, sound, mechanical).

Example:A wire is plugged in to a power outlet on a wall. The electrical energy that flows through the wire transfers into: •light energy when it reaches a lamp.

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•mechanical energy when it reaches a fan.•sound energy when it reaches a radio.•heat energy when it reaches a microwave.

3. Heat energy can be created when matter undergoes a chemical change (burning wood or coal) or when it is produced by another form of energy. It can transfer from a warmer object to a colder object.

Examples of heat energy include: •when wood or other fuels are burned to produce heat•when electric energy is converted to heat in appliances◦hair dryer◦microwave

4. Light energy is a type of wave energy, which is transferred and created by other types of energy. Light energy can also come from the Sun, which is referred to as solar energy.

Light energy can be transferred from (and to) other energy types, such as: •when electrical energy makes a light bulb light up•when light energy is absorbed by plants and made into chemical energy (food)

5. Sound energy is the energy of sound waves as they travel.

Sound energy can be created by other forms of energy, such as: •mechanical energy, when drums are played•electrical energy, when a radio is turned on

6. Chemical energy is the energy found in chemical compounds, such as food or fuel.

Energy Transformation Sample Questions:

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Question 1: Jenna has connected a fan, a radio, and a lamp to an extension cord, which is plugged into the wall. The electrical energy flowing through the extension cord will transfer to which type of energy as it powers the appliances?

A. mechanical energyB. sound energyC. light energyD. all of these

Explanation: The electrical energy flowing through the extension cord with transfer to mechanical energy as it powers the fan, sound energy as it powers the radio, and light energy as it powers the lamp.

Question 2: Mike is playing the drums. As he beats the drums, the mechanical energy of moving the drumsticks is converted to _______.

A. sound energyB. light energyC. electrical energyD. heat energy

Explanation: The mechanical energy of beating the drumsticks is converted into sound energy when Mike plays the drums. When most instruments are played, the musician applies mechanical energy to the instrument, and sound energy results from the instrument, such as in playing the piano, a harp, or a trumpet.

Question 3: A plant receives _______ energy and transforms it into chemical energy for food. A.heat B.mechanicalC.light D.sound

Explanation: A plant receives light energy from the Sun, and uses that to make chemical energy for food.

SPS7. Students will relate transformations and flow of energy within a system.b. Investigate molecular motion as it relates to thermal energy changes in terms of conduction,

convection, and radiation.

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Heat always flows from hotter objects to colder objects, until equilibrium is reached. It will not spontaneously flow in the opposite direction. Heat is measured in Joules (J) and can be transferred by conduction, convection, and radiation.

Conduction•Conduction is the transfer of energy through matter by the direct contact of its particles.•Conduction works best when transferring energy through solids (since the particles are closer together in a solid), but it will also transfer energy in liquids and gases.•This occurs when a source of heat speeds up the particles in one part of the object. These particles strike other particles in the object which strike other particles, in turn, until the kinetic energy of all the particles in the object increases. The increase in kinetic energy causes an increase in temperature and an increase in the object's thermal energy.

A conductor is something that lets heat and electricity go through it.Think of a hot summer day. You sit on a shiny metal slide, OUCH! It's very hot and burns your legs! The slide is made of metal, it is a good conductor. An insulator is something that does not let heat and electricity go through it easily. If you slide down a plastic slide, like on our playground, it is very warm, but it will not burn you like a metal slide. Plastic is a good insulator.

Convection •Convection is the transfer of heat through a fluid such as a liquid or a gas.•As the liquid or gas is heated, the hot part expands and becomes less dense.•Currents facilitate the transfer of heat by convection through liquids and gases.

Radiation •Radiation is the transfer of energy through rays or waves.•The Sun heats the Earth by radiation

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Heat Transfer Questions:1. You might see the air shimmering over a radiator (convection), 2. put your hand on a warm spoon that's been sitting in a hot bowl of soup (conduction), or 3. notice that the sun shine feels warm on your skin (radiation).

SPS7. Students will relate transformations and flow of energy within a system.1. Determine the heat capacity of a substance using mass, specific heat, and temperature.

The first law of thermodynamics is the application of the conservation of energy.States: that the increase in thermal energy of a system equals the work done on the system plus the heat added to the system.

Endothermic vs. ExothermicExothermic- heat energy EXITS the system

- ex. Combustion, evaporation of water- surroundings usually feel warmer

Endothermic- heat energy ENTERS the system- ex. Cold packs, melting ice- surroundings usually feel cooler

Specific heat capacity is also known as ‘specific heat’. It is the energy required to raise 1 gram of a chemical by 1 degree Celsius. It has a unit of J/g°C (or Joules per degree Celsius per gram)

Each material is able to "hold" a certain amount of thermal energy at a given temperature, due to what we call its specific heat. Think of the wide range of temperatures that your feet encounter during a day at the beach. The water may seem cold while the sand feels quite warm. The wood on the boardwalk may feel comfortable, but the blacktop in the parking lot is burning hot. Things will heat up at different rates, due, in part, to their different specific heat values.

So, as you see, temperature is one of the factors that affect the thermal energy of a substance. What is heat? Heat is the transfer of thermal energy from a hotter to a colder object. What we think of as "cold" is really the absence of heat. An object with at a higher temperature can release more heat than the same object at a lower temperature, but temperature is only one of the factors that affect the amount of heat an object can transfer.

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The factors that affect the amount of heat are the same as the factors that affect thermal energy, for reasons that should now be clear to you. Thermal energy is only measurable as heat, during heat transfer. The amount of heat transferred can be found according to the following formula:

amount of heat transferred = mass x specific heat x change in temperatureQ = m * c * ∆T

Sample Problem:C = q/m∆T, where q = heat energy, m = mass, and T = temperature.Remember, ∆T = (Tfinal – Tinitial). Show all work and proper units.

1. A 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature changes from 25°C to 175°C. Calculate the specific heat capacity of iron.

2. To what temperature will a 50.0 g piece of glass raise if it absorbs 5275 joules of heat and its specific heat capacity is 0.50 J/g°C? The initial temperature of the glass is 20.0°C.

SPS7. Students will relate transformations and flow of energy within a system.d. Explain the flow of energy in phase changes through the use of a phase diagram.

Matter can be found in three main states—solid, liquid, and gas—and can move among these states. For instance, solid water can be melted to form liquid water, and liquid water can be evaporated to form water vapor. When matter is transformed from one phase to another, it is said to undergo a phase change or change of state.

The different types of phase change are: Melting transformation of a solid into a liquid Freezing transformation of a liquid into a solid Sublimation transformation of a solid into a gas without first becoming a liquid Deposition transformation of a gas into a solid without first becoming a liquid Vaporization transformation of a liquid into a gas Evaporation vaporization that takes place at the surface of a liquid Condensation transformation of a gas into a liquid

Phase Changes are Physical Changes

Phase changes are physical changes because only the physical properties of the matter change. The mass, chemical composition, and chemical properties of the matter do not change when the substance changes state. A few of the physical properties which can change with a change of state are density, viscosity, and appearance.

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The atoms or molecules in a gas have the same mass as when they are in solid or liquid form, but they are much further apart. This results in a lower density. In fact, the density of a gas is always lower than the same material in liquid or solid form.

Usually, liquids are less dense than the same substance as a solid. Water is a notable exception to this rule. The ability of liquids to flow is described as their viscosity. Liquids experience a change in viscosity when they become a solid or a gas because the particles become either too close together or too far apart to have the ability to flow. Phase Changes and HeatAtoms or molecules in a solid are oriented close together in a regular arrangement. For the particles in a solid to overcome the attractive forces that are holding them in this arrangement, heat must be added to the solid. Atoms or molecules in a liquid are able to move around one another, but are still close together. Heat must also be added to allow the molecules to break away from one another and become a gas. Heat must be gained or lost for matter to change phases. Atoms or molecules in liquids are typically farther apart and are arranged more randomly than those in solids. For the particles in a liquid to become more ordered, heat must be removed from the liquid.

Since particles in gas form are arranged in a way that is even less orderly than in liquids, heat must also be added when gas is formed, either through boiling or sublimation. To form liquids from gases (condensation) or solids from gases (deposition), heat energy must be removed from the gas.

When heat is added to a substance, the energy of the substance increases; When heat is removed from a substance, the energy of the substance decreases. The following diagram shows the relationship between heat and energy for each state of matter.

SPS9. Students will investigate the properties of waves.

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a. Recognize that all waves transfer energy.

Wave is a transfer of energy, in the form of disturbance through some medium, without translocation (movement) of the medium. A wave is a periodic disturbance which travels through a medium from one point in space to the others.

Basic properties of waves include:

Energy is transferred from one place to another in a wave motion.

Motion of the medium (particles of the medium) is usually periodically vibratory.

Only the shape or form of wave travels, not the medium.

1. All waves carry energy through matter or space. They do not carry matter.

2. Waves carry energy that can be transferred or transformed in interactions with matter or other waves.

3. Waves are energy. Waves carry energy from the source out.

4. Waves are either mechanical or electromagnetic. Which one depends on the source of the vibration.

Transverse Wave: Longitudinal Wave:

•Crest—the highest point of a transverse wave

•Trough—the lowest point of a transverse wave

•Amplitude—the distance from the crest (or trough) of a wave to the rest position of the medium

•Wavelength—the distance between a point on one wave and the identical point on the next wave

•Frequency—the number of wave crests that pass by a point each second; measured in hertz (1 Hz = 1 wave/sec)

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•Speed—how fast a wave is traveling; speed (s) = wavelength (λ) x frequency (f)

Types of Waves

Waves can be classified into two groups based on whether or not they require a medium in order to travel.

1. Mechanical waves require a medium in order to travel from one place to another.

2. Electromagnetic waves do not need a medium.

Mechanical Waves

Any wave that requires a medium, such as air, to transfer energy is known as a mechanical wave. These waves cannot transfer energy in a vacuum. Sound waves, water waves, and stadium waves (the kind in which people stand up and then sit down to make a wave) are all examples of mechanical waves.

Ocean waves, such as the ones shown here, are mechanical waves. They cannot transfer energy unless there is some type of material to move through.

Electromagnetic Waves

Any wave that can transfer energy through both a medium and empty space is an electromagnetic wave. All the waves on the electromagnetic spectrum (radio waves, infrared waves, light waves, ultraviolet waves, x-rays, and gamma rays) are examples of electromagnetic waves.

SPS9. Students will investigate the properties of waves.

b. Relate frequency and wavelength to the energy of different types of electromagnetic waves and mechanical waves.

Wavelength and Frequency: They have an inverse relationship.

When wavelength (λ) increases, the frequency (f) decreases (and vice-versa).

17Low Frequency High Frequency

Radiation is defined by its wavelength, frequency, and energy. The wavelength is the distance between peaks in the wave, i.e. the distance from crest to crest. If a wave is passing by a point, the frequency is the time interval between passing peaks.

Frequency = Speed of Light / Wavelength (Hertz :Hz) or Cycles per Second are the basic units of Frequency); Wavelength = Speed of Light / Frequency (Meter is the basic unit for measuring the wavelength. For very small wavelengths microns or nanometers are commonly used.)

SPECTRUM BASED ON WAVELENGTH, FREQUENCY, AND ENERGY

The spectrum of waves can be divided into sections based on wavelength, frequency, or energy. The shortest waves are gamma rays, which have wavelengths of 10e-6 microns or less, carry the most energy, and have the highest frequencies. The longest waves are radio waves, which can have wavelengths of many kilometers, carry the least energy, and have the lowest frequencies.

Visible Light Spectrum is a particular band of electromagnetic radiation that can be seen and sensed by the human eye. This visible part of the electromagnetic spectrum consists of the colors that we see in a rainbow - from reds and oranges, through blues and purples. Each of these colors actually corresponds to a different wavelength of light. Red has longer wavelength than any other colors of the spectrum.

SPS9. Students will investigate the properties of waves.

c. Compare and contrast the characteristics of electromagnetic and mechanical (sound) waves.

1. Waves are either mechanical or electromagnetic.

2. Mechanical waves (sound, ocean waves, seismic) require a medium (air, water, ground) to travel through.

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3. Electromagnetic waves are the most common waves in the universe (X-rays, Ultraviolet, radio, and Light) and can travel through a medium or through the void of space (like the sun’s rays).

4. Mechanical waves are either transverse , longitudinal waves, or a combination of both (i.e. surface waves)

5. In transverse waves, the wave energy moves perpendicular to the matter in the medium. The high point in a transverse wave is called the crest and the low point is called the trough.

6. In Compressional / Longitudinal waves, the wave energy moves parallel to the matter in the medium. The matter in the medium compresses together and expands.

7. The Electromagnetic Spectrum. There are different types of electromagnetic waves. All travel at the same speed, but they have different wavelengths.

SPS9. Students will investigate the properties of waves.

d. Investigate the phenomena of reflection, refraction, interference, and diffraction.

Reflection: when a wave bounces off a surface that it cannot pass through

Refraction: the bending of a wave as it enters a new medium at an angle

Diffraction: the bending of a wave as it moves around an obstacle or passes through a narrow opening.

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Interference: the interaction of two or more waves that combine in a region of overlap

Compare destructive and constructive interference. Both are caused by two or more waves interacting, but constructive interference combines the energies of the two waves into a greater amplitude and destructive interference reduces the energies of the two waves into a smaller amplitude.

SPS9. Students will investigate the properties of waves.

e. Relate the speed of sound to different mediums.

Sound travels through different media at different speeds

Sound typically travels faster in a solid than in a liquid and faster in a liquid than in a gas.

In a denser medium (solids), sound travels faster (in solids, particles are closely arranged) ; relatively slower in liquids and least in gases.

The higher the temperature, the faster the particles of the medium will move increasing the speed of sound

SPS9. Students will investigate the properties of waves.

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f. Explain the Doppler Effect in terms of everyday interactions.

The Doppler effect is a change in the observed wavelength of waves due to motion by the observer or the wave source. Perhaps the most familiar example of the Doppler effect occurs while waiting at a railroad crossing—the pitch of the train's horn increases as the train engine approaches and decreases as it moves away.

For a stationary observer, the frequency of the sound wave they experience from a moving source is greater as the source approaches, than as it gets farther away. The shortest wavelengths (highest frequencies) will occur directly in front of the approaching wave source.

The pitches are different because the observer perceives the sound wavelengths to be shorter as the train approaches and longer as the train moves away. The wavelengths change to the observer because the distance between the source of the signal and the observer is changing through time. At constant velocities, this effect is independent of the observer's distance from the source; instead, it is only dependent on whether the source is approaching or receding.

The Doppler effect can also be observed if the listener is moving and the source of the wave is stationary. The Doppler effect is evident with all types of waves involving moving sources or observers, including sound and light. Electromagnetic radiation from objects throughout the universe exhibits the Doppler effect. Astronomers study this effect to learn more about the universe.

SPS3. Students will distinguish the characteristics and components of radioactivity.

a. Differentiate between fission and fusion.

The process of splitting a nucleus into several smaller nuclei is nuclear fission. The products of a fission reaction usually include several individual neutrons in addition to the smaller nuclei. The total mass of the products is slightly less than the mass of the original nucleus and the neutron. This small amount of missing mass is converted to a tremendous amount of energy during the fission reaction. The series of repeated fission reactions caused by the release of neutrons in each reaction is a chain reaction. A chain reaction can be controlled by adding materials that absorb neutrons. For a chain reaction to occur, a critical mass of material that can undergo fission must be present. The critical mass is the amount of material required so that each fission reaction produces approximately one more fission reaction. If less than the critical mass of material is present, a chain reaction will not occur.

In nuclear fission, nuclei of uranium are split into smaller pieces and large amount of energy will be released. In order to maintain the Chain reaction, mass of uranium used should exceed the Critical mass.

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In nuclear fusion, two nuclei with low masses are combined at high temperatures to form one nucleus of larger mass. Fusion fuses atomic nuclei together, and fission splits nuclei apart. If nuclei are moving fast, they can have enough kinetic energy to overcome the repulsive electrical force between them and get close to each other. Most of the energy given off by the Sun is produced by a process involving the fusion of hydrogen nuclei. In nuclear Fusion, nuclei of hydrogen are joined together and Helium nucleus is formed.

d. Describe nuclear energy, its practical application as an alternative energy source, and its potential problems.

Fissile atoms contain vast amounts of energy

Nuclear fission, the splitting of a heavy atom’s nucleus, releases great amounts of energy. For example the energy it releases is 10 million times greater than is released by the burning of an atom of fossil fuel. Besides it would take many hectares of land covered with solar collectors, wind farms or hydro-electric dams to equal this power.

No greenhouse gases are released by nuclear power plants. Less than one-hundredth of carbon dioxide gas is produced by nuclear power plants compared to coal or gas-fired energy plants.

Cost: The major costs are in building nuclear power plants are usually those of construction and operating the nuclear plant as well as that of waste disposal and cost of decommissioning the plant. The end product, useable energy has been estimated to be around 3 - 5 cents (US) per Kilowatt-Hour.

Major challenges of nuclear energy include:

Nuclear Radiation Accidents

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Although only ever one serious nuclear accident has occurred, in Chernobyl in 1986, such an accident affects many thousands of people, livestock and agricultural production over a large geographical area. In the case of Chernobyl in the Ukraine, nuclear fall-out reached as far as areas of the UK.

Supposedly poor reactor design at Chernobyl allowed the emission of radioactivity and this has not been repeated elsewhere. However one accident is too many.

Other disadvantages include:

Nuclear power requires a large capital cost, involving emergency, containment, radioactive waste and storage systems. Long-term storage of nuclear waste is difficult. Ground water contamination would be a deadly nuclear legacy. But nuclear waste is now a big headache.

SPS5. Students will compare and contrast the phases of matter as they relate to atomic and molecular motion. a. Compare and contrast the atomic/molecular motion of solids, liquids, gases and plasmas.

The four states of matter are: solid, liquid, gas, and plasma.

Why do they differ? They differ:

Based upon particle arrangement

Based upon energy of particles

Based upon distance between particles

• Solids: Solids have a definite shape and a definite volume. Particles of solids are tightly packed, vibrating about a fixed position.

• Liquids: Liquids have an indefinite shape and a definite volume. Particles of liquids are loosely packed, but are far enough apart to slide over one another.

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• Gas: Gases have an indefinite shape, and an indefinite volume. Particles of gases are very far apart and move freely.

• Plasma: A plasma is an ionized gas. Plasmas, like gases have an indefinite shape and an indefinite volume

Matter can be changed from on state in to another either by adding energy or removing energy.

Change of State or Phase Change

Phase Change Term for Phase Change Heat Movement During Phase Change

Solid to liquid Melting Liquid absorbs heat to melt

Liquid to gasVaporization, which includes boiling and evaporation

Heat goes into the liquid as it vaporizes.

Gas to liquid Condensation Heat leaves the gas as it condenses (rain)

Liquid to solid Freezing Liquid gives out heat to become solid

Solid to gas Sublimation Heat goes into the solid as it sublimates.

Gas to solid Deposition Gas releases heat to become a solid

Sublimation: Changing from a solid directly to a gas (dry ice turns to carbon dioxide, snow “disappears” w/out melting.

Deposition: Changing directly from a gas to a solid

b. Relate temperature, pressure, and volume of gases to the behavior of gases.

Relating Temperature & Pressure (at a constant volume)

If the temperature increases, the added thermal energy causes the particles to push harder on the inside surface of the container… this causes the pressure to also go up. If the temperature decreases, the pressure decreases. Example: leaving a basketball outside on a cold night causes the ball to go flat.

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Relating Pressure and Volume (at a constant Temperature)

Boyles Law (Pressure goes up Volume goes down @ constant temperature)

Pressure is inversely proportional to the volume.

BOYLES LAW – As pressure is increased volume will decrease, and conversely; if the pressure is decreased, the volume will increase.

Relating Volume & Temperature (at a constant Pressure)

Charles’s Law- As the temperature increases the volume will also increase; conversely, as the temperature decreases the volume will also decrease. Temperature is directly proportional to volume

SPS2. Students will explore the nature of matter, its classifications, and its system for naming types of matter.

Matter is usually defined as anything that has mass and occupies space.

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a. Calculate density when given a means to determine a substance’s mass and volume.

Density is the mass of an object divided by its volume.

Density often has units of grams per cubic centimeter (g/cm3).

SPS1. Students will investigate our current understanding of the atom.

1. Atom: The smallest unit of an element that retains the chemical properties of that element.

2. Electrons: Negatively charged particles that orbit the nucleus of an atom.

3. Element: A substance that cannot be broken down into smaller components by chemical reactions. There are 92 naturally occurring elements.

4. Isotope: An atom that has the same atomic number as another atom but that has a different atomic mass.

5. Nuclear forces: The binding forces in the nucleus of atoms that act over short distances and help overcome the protons' repelling forces.

6. Nucleus: The positively charged core of an atom that contains most of the atom's mass and all of its protons and neutrons.

7. Neutrons: Particles in the atomic nucleus without an electrical charge. Protons and neutrons have nearly identical masses.

8. Protons: Particles in the atomic nucleus with a positive charge. The number of protons determines the identity of the element.

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a. Examine the structure of the atom in terms of:

• proton, electron, and neutron locations.

• atomic mass and atomic number.

• atoms with different numbers of neutrons (isotopes).

Atoms of an element are not all the same. All atoms of an element have the same number of protons or atomic number, but their number of neutrons can be different. The sum of the protons and neutrons for an atom gives the atoms mass number. The mass number is what is used to identify different atoms or isotopes. Isotopes are atoms of the same element with different mass numbers.

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Explain the relationship of the proton number to the element’s identity.

The atomic number is the number of protons in the nucleus of an atom. Atomic numbers identify elements, because the number of protons is what gives an element its unique identity. Changing the number of protons (and therefore the atomic number) changes the identity of the element.

MASS NUMBER – the total number of protons and neutrons in an atom’s nucleus

ISOTOPE – Atoms with the SAME number of protons but DIFFERENT numbers of neutrons. C-12, C-13, and C-14 are all isotopes of carbon (with 6, 7, and 8 neutrons).

ATOMIC WEIGHT – the average mass of all the atoms of an element. Elements with isotopes have fractional atomic weights, depending on the percentage of each isotope that naturally occurs.

SPS4. Students will investigate the arrangement of the Periodic Table.

a. Determine the trends of the following:

o Number of valence electrons

Valence electrons are the electrons located in the outermost orbit.

Period: each row of the periodic table is called a period. If you read from left to right one proton and one electron are added from one element to the next

Group/Family: Each column of the table is called a group or family. Elements in a group share similar properties. Groups/Families are read from top to bottom.

ALKALI METALS—1st column; highly reactive—form ECl chlorides and E2O oxides ALKALINE EARTH—2nd column TRANSITION METALS—3rd through 12th column HALOGEN—17th column (2nd from right); readily form 1- anions NOBLE GASES—18th column (far right column); very unreactive

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Atoms form Ions:

1. Ions: formed when an atom loses or gains one or more electrons (-charge)

2. Cation: formed when an atom loses an electron (+ charge). All metals are cations

3. Anion: formed when an atom gains an electron (-charge). All non-metals form anions.

o Location of metals, nonmetals, and metalloids

b. Use the Periodic Table to predict the above properties for representative elements.

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Metals Nonmetals Metalloids

Shiny, conducts electricity, ductile, malleable,

Dull, poor conductor, brittle Properties of both metals and nonmetals

Loses electrons when bonding Gains electrons when bonding Can gain or lose electrons

Located to the left of the stairs

Located to the right of the stairs Located on the stairs (except Al and Po)

Usually a solid at room temp. Usually a liquid/gas at room temperature

Usually a solid

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