Physical Physical ScienceScience

Chapter 16Chapter 16

Grade 5Grade 5

Chapter 16- Energy and Chapter 16- Energy and WavesWaves

Lesson 1- Kinetic and Lesson 1- Kinetic and Potential EnergyPotential Energy

►Forms of EnergyForms of Energy Energy is the Energy is the

ability to do workability to do work► Measured in JoulesMeasured in Joules► Energy comes in Energy comes in

different forms different forms such as: Thermal, such as: Thermal, chemical, chemical, electromagnetic, electromagnetic, electrical and electrical and mechanicalmechanical

► Thermal Energy-Thermal Energy- is the motion of the is the motion of the particles in matter, felt as heatparticles in matter, felt as heat

► Electromagnetic energyElectromagnetic energy is visible light, is visible light, microwaves, radio waves and X-raysmicrowaves, radio waves and X-rays

► Chemical Energy-Chemical Energy- can be released during can be released during a chemical reaction, like burning coal, or a a chemical reaction, like burning coal, or a battery in a toy car. battery in a toy car.

► ElectricityElectricity – movement of charges – movement of charges particles. Powers almost everything in your particles. Powers almost everything in your house.house.

►Mechanical Energy-Mechanical Energy- energy an object has energy an object has because of its motion or positionbecause of its motion or position Wind, sound, or falling objectsWind, sound, or falling objects

Answer this:Answer this:

► If a Large Rock is on the edge of a cliff, what If a Large Rock is on the edge of a cliff, what kind of energy does it have?kind of energy does it have?

AnswerAnswer

► Potential Potential Mechanical EnergyMechanical Energy

Kinetic EnergyKinetic Energy

► Kinetic Energy-Kinetic Energy- energy of energy of movement.movement.

► Any moving object Any moving object has kinetic energyhas kinetic energy A bowling ball rolling A bowling ball rolling

down an alleydown an alley Falling rockFalling rock Vibrating objectVibrating object

Potential EnergyPotential Energy

►The energy an The energy an object has stored is object has stored is Potential energy.Potential energy. Rock on a ledgeRock on a ledge Compressed springCompressed spring Rubber band being Rubber band being

heldheld

►When work is done, When work is done, energy transfers energy transfers from one form to from one form to anotheranother

► Example:Example: An An archer pulls back archer pulls back the bow and arrow. the bow and arrow. The bent bow has The bent bow has stored POTENTIAL stored POTENTIAL energy. When it is energy. When it is released, the released, the energy is changed energy is changed to Kinetic, to Kinetic, mechanical energy.mechanical energy.

Calculating Mechanical Calculating Mechanical EnergyEnergy

►When an object with Potential energy When an object with Potential energy starts to move, some of that energy is starts to move, some of that energy is changed to Kinetic energychanged to Kinetic energy

►As the amount of Kinetic energy As the amount of Kinetic energy increases, Potential energy decreasesincreases, Potential energy decreases

►Mechanical Energy-Mechanical Energy- is the SUM of PE is the SUM of PE and KEand KE In a falling object, PE and KE will change, In a falling object, PE and KE will change,

but ME will stay the same.but ME will stay the same.

Lesson 2- How Are Sounds Lesson 2- How Are Sounds MadeMade

Sound ProductionSound Production

► A A mechanical wavemechanical wave forms forms when energy moves when energy moves through a medium or through a medium or matter.matter.

► Transverse WavesTransverse Waves move move perpendicular to the perpendicular to the direction of the wavedirection of the wave Waves in a jump ropeWaves in a jump rope

► Longitudinal WavesLongitudinal Waves move move parallel to the direction of parallel to the direction of the wavethe wave A slinky moving back and A slinky moving back and

forth, forth, Where particles come Where particles come

together they form together they form compressionscompressions

WavesWaves ►Waves are measured by two things:Waves are measured by two things:►AmplitudeAmplitude- how high a wave is from crest - how high a wave is from crest

to trough, (top to bottom)to trough, (top to bottom)►Wavelength- Wavelength- the distance between two the distance between two

waveswaves►Scientists also measure Scientists also measure frequencyfrequency, or , or

how many waves pass per secondhow many waves pass per second Shorter wavelengths have higher frequenciesShorter wavelengths have higher frequencies Longer wavelengths have lower frenquenciesLonger wavelengths have lower frenquencies

Sound WavesSound Waves

► Sound waves are produced Sound waves are produced through vibrationsthrough vibrations The energy of the vibrations The energy of the vibrations

travels through the medium travels through the medium as a longitudinal wave.as a longitudinal wave.

► Waves travel at different Waves travel at different speeds through different speeds through different materials.materials. Metals vibrate more easily Metals vibrate more easily

than rubber. Ex: Tuning forksthan rubber. Ex: Tuning forks Sound waves move faster Sound waves move faster

through solids and liquids through solids and liquids than through gasesthan through gases

PitchPitch

►The properties of sound depend on the The properties of sound depend on the vibrations producedvibrations produced

►PitchPitch is how high or low you perceive is how high or low you perceive an object to bean object to be Depends on the wave’s frequencyDepends on the wave’s frequency Higher frequency, higher pitch (whistle)Higher frequency, higher pitch (whistle) Lower frequency, lower pitch (tuba)Lower frequency, lower pitch (tuba)

VolumeVolume

► Volume-Volume- strength of strength of a vibration causing a vibration causing a sound to be loud a sound to be loud or softor soft

► Sound is measured Sound is measured in decibelsin decibels

Acoustics

► Sound waves can behave Sound waves can behave differently when they hit differently when they hit different materialsdifferent materials

► AcousticsAcoustics is the study of how is the study of how materials affect sound wavesmaterials affect sound waves A sound wave will reflect off A sound wave will reflect off

hard surfaceshard surfaces►Grand Canyon echoesGrand Canyon echoes

Sound waves are absorbed by Sound waves are absorbed by most soft or porous surfacesmost soft or porous surfaces►Cotton and other materials in Cotton and other materials in

recording roomsrecording rooms

Lesson 3- Properties of Lesson 3- Properties of LightLight

Electromagnetic WavesElectromagnetic Waves

►Light Waves are electromagnetic wavesLight Waves are electromagnetic waves Can travel through a medium or vacuumCan travel through a medium or vacuum Examples include: x-rays, gamma rays, UV Examples include: x-rays, gamma rays, UV

rays, visible lightrays, visible light

►Different EM waves have different Different EM waves have different frequencies and wavelengthsfrequencies and wavelengths

►Visible light is seen by humansVisible light is seen by humans Consists of seven different colorsConsists of seven different colors

► Some waves can be Some waves can be harmful to living harmful to living thingsthings

► EM waves interact EM waves interact differently with differently with different materialsdifferent materials Some materials will Some materials will

reflect certain reflect certain wavelengths of wavelengths of color, and absorb color, and absorb others.others.

Example: Apple Example: Apple reflects red and reflects red and absorbs other colorsabsorbs other colors

Reflection and RefractionReflection and Refraction

►Light can be absorbed, reflected or Light can be absorbed, reflected or refracted as it hits an objectrefracted as it hits an object

►ReflectionReflection occurs when a wave occurs when a wave bounced off a materialbounced off a material Ex: looking in a mirrorEx: looking in a mirror

►Refraction-Refraction- when the path of light when the path of light changes from one material to the nextchanges from one material to the next Ex: a pencil looking “broken” in a glass of Ex: a pencil looking “broken” in a glass of

waterwater

► A convex lens beds A convex lens beds light rays toward light rays toward one another.one another.

► A concave lens A concave lens bends light rays bends light rays away from one away from one another.another.

► People with glasses People with glasses use different lenses use different lenses to refocus light and to refocus light and images onto the images onto the retinaretina

Fiber OpticsFiber Optics

► Fiber optics use Fiber optics use total internal total internal reflectionreflection Has helped to Has helped to

improve improve communication communication systems and medical systems and medical procedures procedures

Optical fibers can Optical fibers can transmit light over transmit light over long distanceslong distances