Waves & Energy

Waves & EnergyVideos: Bill Nye, Sound Waves, Pioneer Library#218, Doppler Effect#306, 307, 332, 333, 338 - energy

1VocabularyEnergyWaveAmplitudeConductionConvectionRadiationColor spectrumWavelengthPotential energyKinetic energyLight energyChemical energyMechanical energyWhat is Energy?Energy is defined as the ability to do work

Work is using energy to move something

What are Waves?A wave is a disturbance that transfers energy from place to place.

Most waves need a medium or substance to travel through

Glass, liquids & solids can all be mediums

Moving objects have energy.

A moving object can transfer energy to a medium, producing waves.

Mechanical WavesWaves that REQUIRE a medium through which to travel are called mechanical waves.

Mechanical waves do not carry the medium they travel through with themWaves on the ocean do not move the water molecules with themMolecules stay in place, just bob up and down transferring the energy onward

Mechanical waves are produced when an energy source causes a medium to vibrate

Types of WavesMechanical waves are classified by how they move through a medium. Two types of Mechanical WavesTransverse wavesLongitudinal waves

Transverse WavesTransverse waves move the medium at a right angle to the direction of the waveMoving a rope up and down, crests & troughs

Longitudinal WavesLongitudinal waves move the medium parallel to the direction in which the waves travelLike a slinky being pushed back and forthCompressions: when the coils or waves are close togetherRarefactions: when the coils or waves are farther apart.Example: Sound Properties of Waves FoldableFold your paper into 4 sectionsLabel sections speed, amplitude, frequency, and wavelengthIn each section write:DefinitionHow you measure it in longitudinal and transverse waves3 factsOn the back, draw and label an example of each waveWavesWavelengthAmplitudeFrequencySpeedThe energy of a wave depends on the wavelength

WavelengthA wave travels a certain distance before it starts to repeat its motionThe distance between two corresponding parts of a wave Crest to crest Trough to troughAmplitudeAmplitude is the rise of a wave from the rest position

The more energy a wave has, the greater the amplitude.It takes more energy to make a higher or greater amplitude.Rest positionAmplitudeAmplitude of transverse waves: the maximum distance a wave moves up or down

Amplitude of longitudinal waves: measurement of how compressed or rarefied the waves are.Dense compressions means it has a large amplitudeFrequencyNumber of complete waves that pass a given point in a certain amount of time.If one wave passes by every second, the frequency is 1 wave per second. Frequency is measured in hertz (Hz) 1 HzSpeedLight waves travel faster than sound waves (about a million times faster!)

Speed = how far the wave travels in a given length of time

Speed = distance/time

Related FormulasSpeed, wavelength and frequency are related to one anotherSpeed = Wavelength X frequencyFrequency = Speed/WavelengthWavelength = Speed/FrequencyIf you know two of the variables, you can solve for the otherIf you increase the frequency, the wavelength decreasesWorksheet for HW16PracticeComplete the practice Wave Math worksheet for homework!What are Waves?Waves that do not require a medium to travel are called electromagnetic wavesLight from the sun

Electromagnetic WavesTransverse wave that transfers electrical and magnetic energy

Moves at the speed of light (186,000 miles per second)

Do not require a medium, so they can travel through empty space, like space (vacuum)

Electromagnetic SpectrumAll electromagnetic waves travel at the same speed, but they have different wavelengths and frequencies.

The electromagnetic spectrum is the complete range of electromagnetic waves in order of increasing frequency

Electromagnetic SpectrumMade up of:Radio waves-radio, tv, microwavesInfrared rays-heat lamps, infrared camerasVisible light-colors, light we seeUltraviolet rays-rays from the sunX-rays-medicine, engineeringGamma rays-some radioactive materialsElectromagnetic ProjectDraw and label the Electromagnetic Spectrum.

Follow the example I show.

Use page O74.Waves Mini-LabNeeded materials: string, water, container, dropper,Create an example of a transverse wave with stringUsing pages O 24, follow the lab instructions. Answer the analysis questions. On pg 24 do not answer question 6. Write & fill in the table. WorksheetComplete the worksheet Properties of WavesYou may use your notes, not your neighbor!Complete the worksheet Interactions of Waves. Use book pages O 17-23.Properties of WavesComplete the worksheet Waves & EnergyYou may use your book or notes as a reference if necessary.Waves Reading & WorksheetRead pages O 17-26. Use the worksheet provided as a guide to your readingComplete the worksheet Interactions of WavesWavesElectromagneticTransverse WavesDo need a ________ to travel through.Examples of EM waves: (pg O 74)Highest parts called ____.Lowest parts called ________._____ waves.Spread-out parts called ______.Dont need a ________to travel through.Close-together parts called ___.LabTuning Forks, from the book manual.ENERGY!List types of energy:LightSoundEarthquake wavesHeatWind?ElectricalChemical NuclearEnergy is the ability to do work or cause changeWhen an object is moved because of energy, the energy is transferred to the objectEnergy is measured in JOULES (J)EnergyThree mini-labs to complete with observations1.Compare the transfer of energy through various mediumsSoundLightHeatEarthquake wavesHeatHeat is thermal energy moving from a warmer object to a cooler object. The energy depends on the movement of the atomslots of movement = higher heatDoes temperature rise at the same rate for everything? Hot sand & cold water.Specific Heat: amount of heat needed to increase the temperature but the temperature does not increase at the same rate for everythingHow is heat transferred?

How is heat transferred?Conduction: heat is transferred from one object to another without the movement of matter.Examples?Convection: heat is transferred by the movement of currents within a fluid.Examples?Radiation: transfer of energy by electromagnetic wavesExamples?Heat Transfer Mini-LabCompare the transfer of heat by conduction, convection & radiation. Provide examples of each

Light Energy, AKA Electromagnetic Can transfer energy without a mediumTransverse wave that transfers electrical and magnetic energy through vibrationLight behaves like waves and packets at the same timeElectromagnetic waves have the same speed in a vacuum but have different wavelengths and frequenciesThe amount of energy carried by an EM wave increases with frequencyEM spectrum made up of radio waves, microwaves, infrared waves, visible light, Ultraviolet waves, X-rays, Gamma rays. See page O 75

Light Energy Mini-LabDemonstrate how white light can be separated into the visible color spectrum.As light passes through a prism, the waves are bent or refractedRed wavelengths bend the leastComplete five different observations with the prisms. For each, draw (using the colored pencils) the way you see the light separated. Use each of the light sources and try at least two different prisms.Potential & Kinetic EnergyKinetic Energy: The energy an object has due to its motionWhat can effect kinetic energy?Velocity has a greater impact on effecting the overall K.E.Mass more mass means more E to make it moveK.E. = X Mass X Velocity ^2Potential Energy: stored energy that results from the position or shape of an objectGravitational, elasticPotential & Kinetic EnergyMechanical energy is the combination of kinetic and potential energyLets talk PENDULUM: draw a picture, label potential and kinetic Lets talk bouncing ball

Are these examples cyclic

Conversion of EnergyMost forms of energy can be transformed into another type of energyMechanical (movement) to electrical, such as a damToaster: Electrical to heatCell phone: Electrical to electromagneticYour body:Chemical to mechanical, Chemical to thermalResponse to EnergyPlant to sunlight?Humans to light, sound, motionCockroaches to light intensityName some devices that help people sense types of energy: i.e., seismographReviewSection MPage 201- 202: 1, 3, 5-9, 11-15, 19, 23Section OPage 31: 1-7Page 32: 9-11, 13, 19Page 33: 1, 2, 3, 5, 6Page 101: 1, 2, 3, 7Page 102: 11, 13, 14, 15Page 103: 1, 2, 3, 4, 6