Presentation on theme: "Types of Energy Mechanical Thermal Chemical Nuclear Electrical Radiant"— Presentation transcript:
1Types of Energy Mechanical Thermal Chemical Nuclear Electrical Radiant Table of ContentsTypes of EnergyMechanicalThermalChemicalNuclearElectricalRadiant
2Mechanical Energy Review 4Mechanical Energy ReviewME = PE + KEKE = ½ m v2greatest at position 2GPE = mghgreatest at position 1 and 5
36.1Thermal EnergyThe sum of the kinetic and potential energy of all the particles in an object is the thermal energy of the object.
4Temperature and Heat6.1Matter in MotionThe faster they move, the more kinetic energy they have.This figure shows that particles move faster in hot objects than in cooler objects.
5Transfer Thermal Energy Transferring Thermal Energy6.2Transfer Thermal EnergyThermal energy is transferred when one end of a metal spoon is heated by a Bunsen burner.The kinetic energy of the particles near the flame increases.
6Transfer Thermal Energy Transferring Thermal Energy6.2Transfer Thermal EnergyKinetic energy is transferred when these particles collide with neighboring particles.As these collisions continue, thermal energy is transferred from one end of the spoon to the other end of the spoon.
7Radiant Energy and Matter Transferring Thermal Energy6.2Radiant Energy and MatterDifferent materials on Earth absorb radiation in different amounts resulting in uneven heating.Sea breezes and Land breezes are examples of this.Natural convection currents are created.
8Internal Combustion Engines Using Heat6.3Internal Combustion EnginesA car engine is an internal combustion engineEach cylinder contains a piston that moves up and down (a stroke).The heated material in the cylinders expands forcing the piston down.As exhaust gases are released, the piston comes up.As the crankshaft moves with the piston, it turns vital parts of the car.
9Internal Combustion Engines Using Heat6.3Internal Combustion Engines
10Chemical EnergyChemical energy comes from energy release when chemical bonds are broken or formed.When we eat, we break the bonds in our food to release energy to be used by our body.Same goes for chemical fuel used for other reasons.
11Chemical Energy Sources 9.1Chemical Energy SourcesCompared to other fuels such as wood, the chemical energy that is stored in fossil fuels is more concentrated.For example, burning 1 kg of coal releases two to three times as much energy as burning 1 kg of wood.
12Fossil Fuels9.1PetroleumPetroleum is a highly flammable liquid formed by decayed ancient organisms, such as microscopic plankton and algae.It is one of the fossil fuels.The key ingredient to fossil fuelis a carbon hydrogen bondcalled a hydrocarbon.Carbon is found in all living and once living things.
13Nuclear Energy 9.2 Nuclear Energy is a type of chemical energy A nuclear power plant generates electricity using the energy released in nuclear fission.The sun generates energytransferred as lightby nuclear fusion.Insert Figure 10 on page 263
14Nuclear Fission9.2When a neutron strikes the nucleus of a U-235 atom, the nucleus splits apart into two smaller nuclei.In the process -two or three neutrons are emitted, -smaller nuclei are called fission products of barium and krypton are created, -and energy is released.Insert Figure 10 on page 263
15Nuclear Fusion9.2Thermonuclear fusion is the joining together of small nuclei at high temperatures.2 hydrogen atoms fuse to form a helium atom of less massThe mass lost turns into energy by E=mc2Insert Figure 10 on page 263
167.1Electrical EnergyAtoms contain particles called protons, neutrons, and electrons.Protons are positively chargedElectrons have a negative charge,Neutrons have no electric charge.
17Electric Charge7.1Static ElectricityWhen you walk on the carpet, electrons are transferred from the carpet to the soles of your shoes.Your shoe soles become negatively charged.The carpet lost electrons and is positively charge.The accumulation of excess electric charge on an object is called static electricity.
18Lightning 7.1 Lightning is a large static discharge. Static Charge7.1LightningLightning is a large static discharge.A static discharge is a transfer of charge between two objectsA thundercloud is a mighty generator of static electricity. As air masses move and swirl in the cloud, areas of positive and negative charge build up.
19Static Charge7.1LightningEventually, enough charge builds up to cause a static discharge between the cloud and the ground.As the electric charges move through the air, they collide with atoms and molecules. These collisions cause the atoms and molecules in air to emit light.
20Current and Voltage Difference Electric Current7.2Current and Voltage DifferenceThe net movement of electric charges in a single direction is an electric current.When an electric current flows in the wire, electrons drift in the direction that the current flows.Electric current is measured in amperes (Amps).
21Electric Current7.2Voltage DifferenceElectric charge flows from higher voltage to lower voltage.A voltage difference is related to the force that causes electric charges to flow. Voltage difference is measured in volts.
22Conservation of Charge Electric Charge7.1Conservation of ChargeLaw of conservation of charge, charge can be transferred, but it cannot be created or destroyed.Whenever an object becomes charged, electric charges have moved from one place to another.
23Electric Charge7.1ConductorsA material in which electrons are able to move easily is a conductor.The best electrical conductors are metals.The atoms in metals have electrons that are able to move easily through the material.
24Electric Charge7.1InsulatorsA material in which electrons are not able to move easily is an insulator.Electrons are held tightly to atoms in insulators.Most plastics are insulators.The plastic coating around electric wires prevents a dangerous electric shock when you touch the wire.
25Electric Current7.2Electric CircuitsA closed path that electric current follows is a circuit.If the circuit is broken by removing the battery, or the light bulb, or one of the wires, current will not flow.
26Resisting the Flow of Current Electric Current7.2Resisting the Flow of CurrentResistance is the tendency for a material to oppose the flow of electrons, changing electrical energy into thermal energy and light.Resistance is measured in ohms ().Depends on temperature, length, and diameter: hotter, longer, thinner increases resistance
27Electric Current7.2Ohm's LawThe voltage difference, resistance, and current in a circuit are related.According to Ohm's law, the current in a circuit equals the voltage difference divided by the resistance.Ohm's law provides a way to measure the resistance of objects and materials. First the equation above is written as: I = V/R
28Series Circuits 7.3 One kind of circuit is called a series circuit. Electrical Energy7.3Series CircuitsOne kind of circuit is called a series circuit.In a series circuit, the current has only one loop to flow through.Series circuits are used in flashlights and some holiday lights.
29Parallel Circuits 7.3 Houses are wired with parallel circuits. Electrical Energy7.3Parallel CircuitsHouses are wired with parallel circuits.Parallel circuits contain two or more branches for current to move through.The current can flow through both or either of the branches.
30Electrical Energy7.3Household CircuitsThe main switch and circuit breaker or fuse box serve as an electrical headquarters for your home.Parallel circuits branch out from the box to wall sockets, major appliances, and lights.
31Electrical Energy7.3Household CircuitsTo protect against overheating of the wires, all household circuits contain either a fuse or a circuit breaker.The rate at which electrical energy is converted to another form of energy is the electric power.
32Magnetism8.1Magnetic DomainsMagnetic material contains domains of enormous number of atoms that align their charges.Domains are also aligned creating a magnetic field with polar ends.
33Magnetism8.1Magnetic FieldA magnetic field exerts a force on other magnets and objects made of magnetic materials.The magnetic field is strongest close to the magnet and weaker far away.The field also has direction.
34Magnetism8.1Magnetic PolesMagnetic poles are where the magnetic force exerted by the magnet is strongest.Like poles (ie.2 north poles or 2 south poles) repel each other.Opposite poles (ie. north poles and south poles) attract each other.
35Earth’s Magnetic Field Magnetism8.1Earth’s Magnetic FieldThe earth is a large magnet due to a solid inner core of iron and nickel surrounded by a spinning layer of liquid iron and nickel.
36Earth’s Magnetic Field Magnetism8.1Earth’s Magnetic FieldA compass can help determine direction because the north pole of the compass needle points to the northern geographic pole which is actually a south magnet pole.
37Moving Charges and Magnetic Fields Electricity and Magnetism8.2Moving Charges and Magnetic FieldsIt is now known that moving charges, like those in an electric current, produce magnetic fields.Around a current-carrying wire the magnetic field lines form circles.
38Electricity and Magnetism 8.2ElectromagnetsAn electromagnet is a temporary magnet made by wrapping a wire coil carrying a current around an iron core.The magnetic field inside the loop is stronger than the field around a straight wire.A single wire wrapped into a cylindrical wire coil is called a solenoid.
39Electricity and Magnetism 8.2Electric MotorsAn electric motor is a device that changes electrical energy into mechanical energy.Step 1. When a current flows in the coil, the magnetic forces between the permanent magnet and the coil cause the coil to rotate.
40Electricity and Magnetism 8.2Making the Motor SpinStep 2. In this position, the brushes are not in contact with the commutator and no current flows in the coil.The inertia of the coil keeps it rotating.
41Electricity and Magnetism 8.2Making the Motor SpinStep 3. The commutator reverses the direction of the current in the coil.This flips the north and south poles of the magnetic field around the coil.
42Electricity and Magnetism 8.2Making the Motor SpinStep 4. The coil rotates until its poles are opposite the poles of the permanent magnet.The commutator reverses the current, and the coil keeps rotating.
43Producing Electric Current 8.3GeneratorsA generator uses electromagnetic induction to transform mechanical energy into electrical energy.In this type of generator, a current is produced in the coil as the coil rotates between the poles of a permanent magnet.
44Generating Electricity for Homes Producing Electric Current8.3Generating Electricity for HomesThe rotating magnets are connected to a turbine, a large wheel that rotates when pushed by water, wind, or steam.
45Direct and Alternating Currents Producing Electric Current8.3Direct and Alternating CurrentsA battery produces a direct current.Direct current (DC) flows only in one direction through a wire.Power companies produce alternating current (AC) reverses the direction of the current in a regular pattern.
46Transmitting Electrical Energy Producing Electric Current8.3Transmitting Electrical EnergyWhen the electric energy is transmitted along power lines, some of the electrical energy is converted into heat due to the electrical resistance of the wires.The electrical resistance and heat production increases as the wires get longer.
47Transmitting Electrical Energy Producing Electric Current8.3Transmitting Electrical EnergyOne way to reduce the heat produced in a power line is to transmit the electrical energy at high voltages, typically around 150,000 V.Electrical energy at such high voltage cannot enter your home safely, nor can it be used in home appliances.A transformer is used to decrease the voltage.
48Producing Electric Current 8.3TransformersA transformer is a device that increases or decreases the voltage of an alternating current.A transformer is made of a primary coil and a secondary coil.These wire coils are wrapped around the same iron core.
49Producing Electric Current 8.3TransformersA transformer that increases the voltage so that the output voltage is greater than the input voltage.A transformer that decreases the voltage so that the output voltage is less than the input voltage.
50Transmitting Alternating Current Producing Electric Current8.3Transmitting Alternating CurrentThis figure shows how step-up and step-down transformers are used in transmitting electrical energy from power plants to your home.
51A wave will travel only as long as it has energy to carry. The Nature of Waves10.1A wave is a repeating disturbance or movement that transfers energy through matter or space.The waves don’t carry matter along with them. Only the energy carried by the waves moves forward.A wave will travel only as long as it has energy to carry.
52The Nature of Waves10.1Mechanical WavesMechanical waves are waves that travel through matter.The matter the waves travel through is called a medium.The medium can be a solid, a liquid, a gas, or a combination of these.
53A transverse wave moves up and down. Types of Mechanical of Waves10.1A transverse wave moves up and down.A compressional wave moves back and forth.
54Examples of Mechanical Waves 10.1Water Waves a mechanical wave of a combination of transverse and compression action.Seismic Waves are also a combination of both actions that go through the Earth’s crust
55Wave Properties10.2The Parts of a WaveA transverse wave has alternating high points, called crests, and low points, called troughs.
56Wave Properties10.2WavelengthA wavelength is the distance between one point on a wave and the nearest point just like it.For transverse waves the wavelength is the distance from crest to crest or trough to trough.
57Wave Properties10.2Frequency and PeriodThe frequency of a wave is the number of wavelengths that pass a fixed point each second.You can find the frequency of a transverse wave by counting the number of crests or troughs that pass by a point each second.Frequency is expressed in hertz (Hz).
58Calculating Wave Speed Wave Properties10.2Calculating Wave SpeedYou can calculate the speed of a wave represented by v by multiplying its frequency times its wavelength.
59Amplitude of Transverse Waves Wave Properties10.2Amplitude of Transverse WavesThe amplitude of any transverse wave is the distance from the crest or trough of the wave to the rest position of the medium.
60The Behavior of Waves10.3The Law of ReflectionThe beam striking the mirror is called the incident beam.The beam that bounces off the mirror is called the reflected beam.
61The Behavior of Waves10.3RefractionRefraction is the bending of a wave caused by a change in its speed as it moves from one medium to another.
62The Behavior of Waves10.3DiffractionWaves also can be diffracted when they pass through a narrow opening.After they pass through the opening, the waves spread out and bend.
63The Behavior of Waves10.3InterferenceWhen two or more waves overlap and combine to form a new wave, the process is called interference. Interference occurs while two waves are overlapping.
64Constructive Interference The Behavior of Waves10.3Constructive InterferenceIn constructive interference, the waves add together.The amplitude of the new wave that forms is equal to the sum of the amplitudes of the original waves.
65Destructive Interference The Behavior of Waves10.3Destructive InterferenceIn destructive interference, the waves subtract from each other as they overlap.This happens when the crests of one transverse wave meet the troughs of another transverse wave.
66Electromagnetic Waves What are electromagnetic waves?12.1Electromagnetic WavesElectromagnetic waves are made by vibrating electric charges and can travel through space where matter is not present.Instead of transferring energy from particle to particle, electromagnetic waves travel by transferring energy between vibrating electric and magnetic fields.
67What are electromagnetic waves? 12.1Wave SpeedAll electromagnetic waves travel at 300,000 km/s in the vacuum of space.The speed of electromagnetic waves in space is usually called the “speed of light.”As the frequency increases, the wavelength becomes smaller.
68What are electromagnetic waves? 12.1Waves and ParticlesEnergy carried by a wave depends on its amplitude and not its frequency.Albert Einstein stated electromagnetic waves can behave as a particle, called a photon, whose energy depends on the frequency of the waves.
69The Electromagnetic Spectrum 12.2A Range of FrequenciesElectromagnetic waves can have a wide variety of frequencies.The entire range of electromagnetic wave frequencies is known as the electromagnetic spectrum.
70The Electromagnetic Spectrum 12.2Visible LightVisible light is the range of electromagnetic waves that you can detect with your eyes.Visible light has wavelengths around 750 billionths to 400 billionths of a meter.
71Radiant Energy and Light The Behavior of Light13.1Radiant Energy and LightLight is the result of radiant energy traveling in electromagnetic waves that hit materials and excite the material’s electrons.Those electrons move farther away from the nucleusWhen it returns the electron gives off photons of electromagnetic waves.
72The Behavior of Light13.1The Law of ReflectionBecause light behaves as a wave, it obeys the law of reflection.According to the law of reflection, light is reflected so that the angle of incidence always equals the angle of reflection.
73Light and Color13.2ColorsAn object’s color depends on the wavelengths of light it reflects.You know that white light is a blend of all colors of visible light.This image shows white light striking a green leaf. Only the green light is reflected to your eyes.
74Refraction and Rainbows The Behavior of Light13.1Refraction and RainbowsRefraction is caused by a change in the speed of a wave when it passes from one material to another.The refraction of the different wavelengths can cause white light from the Sun to separate into the individual colors of visible light.Like prisms, rain droplets also refract light.
75Light and Color13.2Light and the EyeIn a healthy eye, light enters and is focused on the retina, an area on the inside of your eyeball.The retina is made up of two types of cells that absorb light.These cells absorb light energy, chemical reactions convert light energy into nerve impulses that are transmitted to the brain.
76Light and Color13.2Light and the EyeOne type of cell in the retina, called a cone, allows you to distinguish colors and detailed shapes of objects and are most effective in daytime vision.The second type of cell, called a rod, is sensitive to dim light and is useful for night vision.Red, green, and blue are the primary colors of light. When mixed together in equal amounts they produce white light.
77Light and Color13.2Mixing ColorsA pigment is a colored material that is used to change the color of other substances.The color of a pigment results from the different wavelengths of light that the pigment reflects.A primary pigment’s color depends on the color of light it reflects.If all the primary light colors are reflected in equal amounts, the object appears white.
78Mirrors14.1MirrorsThe image formed when an object is placed by a mirror changes depending on its position in relation to the mirror’s focal point.If the surface of a mirror is curved inward, it is called a concave mirror.The mirrors are often used to magnify objects.
79Mirrors14.1Convex MirrorsA mirror that curves outward like the back of a spoon is called a convex mirror.Objects tend to appear smaller and farther away such as in rear view and side mirrors of cars.
80Lenses14.2What is a lens?A lens is a transparent material with at least one curved surface that causes light rays to bend, or refract, as they pass through.The image that a lens forms depends on the shape of the lens.The type of image a lens forms depends on where the object is relative to the focal point.Like curved mirrors, a lens can be convex or concave.
81Lenses14.2Convex LensesA convex lens is thicker in the middle than at the edges.When the candle is more than two focal lengths away from the lens, its image is real, reduced, and upside down.
82Lenses14.2Concave LensesA concave lens is thinner in the middle and thicker at the edges.The image is always virtual, upright, and smaller than the actual object is.
83Focusing on Near and Far Lenses14.2Focusing on Near and FarAs an object gets farther from your eye, the focal length of the lens has to increase.The muscles around the lens stretch it so it has a less convex shape.
84Focusing on Near and Far Lenses14.2Focusing on Near and FarBut when you focus on a nearby object, these muscles make the lens more curved, causing the focal length to decrease.
85Vision Problems—Farsightedness Lenses14.2Vision Problems—FarsightednessIf you can see distant objects clearly but can’t bring nearby objects into focus, then you are farsighted.
86Lenses14.2FarsightednessTo correct the problem, convex lenses cause incoming light rays to converge before they enter the eye.
87Lenses14.2AstigmatismAnother vision problem, called astigmatism occurs when the surface of the cornea is curved unevenly.When people have astigmatism, their corneas are more oval than round in shape.Astigmatism causes blurry vision at all distances.
88Lenses14.2NearsightednessIf you have nearsighted friends, you know that they can see clearly only when objects are nearby.When a nearsighted person looks at distant objects, the light rays from the objects are focused in front of the retina.
89Lenses14.2NearsightednessA concave lens in front of a nearsighted eye will diverge the light rays so they are focused on the retina.