Presentation on theme: "WAVES CARRY ENERGY! MECHANICAL WAVES"— Presentation transcript:
1 WAVES CARRY ENERGY! MECHANICAL WAVES Waves are rhythmic disturbances that carry ENERGY without carryingmatter. Molecules transport the energy in a wave by colliding with themolecules around them. Mechanical waves travel through matter bycreating vibrations in a medium – solid, liquid or gas. Examples: Sound,water or seismic waves.MECHANICAL WAVESUse matter to transfer ENERGY from particle to particleMatter = Medium(requires it)TRANSVERSECOMPRESSIONAL(Longitudinal)
2 WAVE PROPERTIES WAVELENGTH CREST AMPLITUDE TROUGH FREQUENCY POSITIONTROUGHFREQUENCYCREST – highest point of a waveTROUGH – lowest point of a waveWAVELENGTH – distance from peak to peakAMPLITUDE – the distance a wave rises/falls from its rest positionFREQUENCY – the number of waves passing a given point
3 Frequency and Wavelength Longer wavelengths Larger frequenciesresult in smaller result in shorterfrequencies. wavelengths.As the frequency of a wave increases,its wavelength decreases.Frequency and wavelength are related!
4 TRANSVERSE WAVES EXAMPLES: oscillating, repetitive motion in which the medium moves at right anglesto the wave directionparticles of the medium moving perpendicular (moves at right angle)WAVELENGTHCRESTAMPLITUDETROUGHEXAMPLES:Slinky, secondary seismic wave, ocean waves,light waves, guitar strings, and a stadium wave
5 ] ] ] COMPRESSIONAL WAVES particles of the medium moving parallel to the direction of the waveoscillating, repetitive motion that moves in the same direction as the mediummatter in the medium moves forward or backward in the same directionof the waveTransfers energy from molecule to molecule through solids, liquids & gasesNeeds a medium to travel – space is a vacuum without air – sound does nottravel in space]RAREFACTION]]COMPRESSIONWAVELENGTHEXAMPLES -Sound, dominoes, primary seismic waves, bats hearing, sonar
6 Electromagnetic waves are not caused by a disturbance of particles in a medium. Instead, it is produced by an interaction between an electric and a magnetic field.Field - force or push in a regionSpeed of light – 300,000 kmpsMedium - matterElectromagnetic waves travel ina vacuum at the same speed
8 ELECTROMAGNETIC WAVES Are transverse waves that do not require matter to carry energy.They are produced by the motion of electrically charged particles.They can travel through solid, liquids or gas faster than mechanicalwaves.They can also travel through space, or through a vacuum whereno matter exist.
9 LIGHTLight is a electromagnetic wave that travels through air at about 300,000 km/s.Bright lights have greater amplitudes (more energy) than the waves that make up dim light.Because frequency and wavelength are related, either the wavelength or frequency of a light wave determines the color of the light. Blue light has a larger frequency and shorter wavelength than red light. Red light has a shorter frequency and a longer wavelength.Light travels faster through gases than in solids or liquids.Example: speed of light is one and a half times faster in air than it is in glass.
11 LIGHT WAVE BEHAVIOR Reflected Absorbed Transmitted Light rays that come in contactwith a object that reflects it willbounce right back at the sameangle it came in at - like yourreflection In a mirror.ReflectedAbsorbedTransmittedLight rays that come in contactwith a dark object will beabsorbed into it, making theobject warmer - like your darkcolored shirt or car.Light rays that come in contactwith something that istranslucent, or clear, will“transmit” or go through theobject - like a window or a glass.
12 A MIRAGE IS AN ILLUSION CAUSED BY THE REFRACTION OF LIGHT WAVES, MAKINGOBJECTS THAT ARE FAR AWAY TO BENEARBY, FLOATING IN THE AIR ORUPSIDE DOWN.
13 Light rays refract as they enter and leave each rain drop Light rays refract as they enter and leave each rain drop. Each color refracts at different angles because of their different wavelengths, so they separate into the colors of the spectrum.
14 As sunlight passes through the atmosphere, its wavelength is scattered by particles of dust in the air. Red and yellow wavelengths pass through the air directly, while blue light is scattered. It is this scattered blue light (short wavelength) that reaches our eyeswhen we see blue sky.
15 REFRACTION Examples: Eyeglasses Binoculars Telescopes Microscopes Refraction is the bending of a wave as it movesfrom one medium into another.Air (less dense)Water (dense)NormalExamples:EyeglassesBinocularsTelescopesMicroscopesANGLE OF INCIDENCERefractsAngle ofrefraction
16 Incident RayNormalReflective RayReflection occurs when a wave strikes an object and bounces off.
17 INTERFERENCE Destructive – a wave with a smaller amplitude is formed. The ability of 2 waves to combineand form a new wave when they overlap.Constructive = combines tomake a new wave, increasingits amplitude.INTERFERENCEPg. 202
20 The diffraction grating has thousands of tiny parallel lines etched into it. Diffraction is the bending of waves around barriers or through openings.What colors do you see through the diffraction grating?What are some examples of patterns you can observe?Where did all the beautiful colors come from?Have you ever used a prism to separate white light into its many colors?If so, what did you observe?
21 SOUNDSound is a mechanical wave that travels through air at about 340 m/s or 1100 ft. per second.Loud sound waves are greater amplitudes than soft sound waves.Loud sounds carry more energy than soft sounds.Sound travels faster in a solid than a liquid, and faster in a liquid than a gas.In a sound wave, either the wavelength or frequency determines the pitch.Pitch is the high or low of a sound.Sound level (loudness) is measured in units called decibels.Vocal cords produce sound by vibration.As the frequency of a sound wave increases, its wavelength decreases.
22 DIFFRACTION Diffraction is the bending of waves around a barrier. Example: Music going into another room.Light shining into the next room.Light waves do not diffract as much as soundwaves do.DIFFRACTION1.What colors do you see through the diffraction grating?2. What are some examples of patterns you can observe?3. Where did all the beautiful colors come from?4. Have you ever used a prism to separate white light into its many colors?
23 Sound – Pitch and Loudness Pitch - depends on frequencyHigh frequency – high pitchLow frequency – low pitchLoudness – depends on energy of amplitudeIntensity of the wave – amount of energy in a certain amount of timeThe greater the amplitude, the louder the sound
24 ] ] ] COMPRESSIONAL WAVES particles of the medium moving parallel to the direction of the waveoscillating, repetitive motion that moves in the same direction as the mediummatter in the medium moves forward or backward in the same directionof the waveTransfers energy from molecule to molecule through solids, liquids & gasesNeeds a medium to travel – space is a vacuum without air – sound does nottravel in space]RAREFACTION]]COMPRESSIONWAVELENGTHEXAMPLES -Sound, dominoes, primary seismic waves, bats hearing, sonar