Physics Unit 5 Waves Light & Sound
Wave A rhythmic disturbance that transfers energy through matter and/or a vacuum Material a wave travels through is called the medium 2 types of waves: 1. Transverse 2. Compressional (Longitudinal)
Transverse Matter in the wave moves at right angles to the direction of the wave front Crest Wavelength (λ) amplitude Trough mid line (resting position) Examples: gamma radiation, x-ray, UV, visible light, infrared, microwave, radio, TV, water
Compressional (Longitudinal) Matter moves in the same direction as (along with) the wave front compression λ rarefaction Example: sound
Transverse & Compressional Amplitude (A) -determined by amount of energy Wavelength (λ) -determined by the wave frequency Frequency (f) -number of waves per second -measured in hertz (Hz)
Transverse & Compressional Velocity (v) -v = λf -varies based on temperature, what it is traveling thru -stays the same in a given medium velocity of light (all transverse waves) - 300,000,000 m/s velocity of sound (longitudinal waves) -330 m/s
Frequency Comparisons Transverse Longitudinal High frequency -purple light High frequency -High pitch Low frequency -red light low frequency -low pitch
Amplitude Comparisons Transverse Longitudinal High amplitude -bright light High amplitude -loud Low amplitude -dim light low amplitude -quiet
Transverse vs. Longitudinal
Check up Which has a longer λ? -A Which has higher frequency? -B Which has higher amplitude? -both same
Physics Unit 5 Electromagnetic Spectrum
Electromagnetic Spectrum Transverse waves that go in order of increasing frequencies (decreasing wavelengths) some wave frequencies overlap
1. 3. Electromagnetic Spectrum 2. 4. 5. 6. 7. 8. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.
Electromagnetic Spectrum 1.TV 3. 2. 4. 5. 6. 7. 8. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.
Electromagnetic Spectrum 1.TV 3. 2.Radio 4. 5. 6. 7. 8. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.
Electromagnetic Spectrum 1.TV 3.microwaves 2.Radio 4. 5. 6. 7. 8. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.
Electromagnetic Spectrum 1.TV 3.microwaves 2.Radio 4.infrared 5. 6. 7. 8. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6. 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6. 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6. 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6. 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6. 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow green
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6. 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow green blue
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6. 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow green blue violet
Electromagnetic Spectrum 1.TV 5.visible light 3.microwaves 8. 6.ultraviolet 2.Radio 4.infrared 7. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow green blue violet
1.TV Electromagnetic Spectrum 5.visible light 3.microwaves 6.ultraviolet 2.Radio 4.infrared 7.x-ray 8. 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow green blue violet
1.TV Electromagnetic Spectrum 5.visible light 3.microwaves 6.ultraviolet 2.Radio 4.infrared 7.x-ray 8.Gamma 9. frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow green blue violet
1.TV Electromagnetic Spectrum 5.visible light 3.microwaves 6.ultraviolet 2.Radio 4.infrared 7.x-ray 8.Gamma 9.Low frequency 10. wavelength 11. frequency 12. wavelength 13.red orange yellow green blue violet
1.TV Electromagnetic Spectrum 5.visible light 3.microwaves 6.ultraviolet 2.Radio 4.infrared 7.x-ray 8.Gamma 9.Low frequency 10. wavelength 11.High frequency 12. wavelength 13.red orange yellow green blue violet
1.TV Electromagnetic Spectrum 5.visible light 3.microwaves 6.ultraviolet 2.Radio 4.infrared 7.x-ray 8.Gamma 9.Low frequency 10.Long wavelength 11.High frequency 12. wavelength 13.red orange yellow green blue violet
1.TV Electromagnetic Spectrum 5.visible light 3.microwaves 6.ultraviolet 2.Radio 4.infrared 7.x-ray 8.Gamma 9.Low frequency 10.Long wavelength 11.High frequency 12.Short wavelength 13.red orange yellow green blue violet
Exploring Electromagnetic Spectrum
Doppler Effect The apparent shift in frequency caused by the movement of the sound source or the movement of the observer. When the waves get crunched together (in front of the moving sound) the frequency of the wave is increased and the sound is high in pitch. When the waves get spread apart (behind the moving sound) the frequency of the wave is decreased and the sound is low in pitch.
Doppler Effect Low pitch High pitch
Doppler Effect Used in police radar to determine the speed of an oncoming car. Used by meteorologists to determine the size and speed of an approaching frontal system. Explains the sound you hear when listening to a Nascar race!
Waves Since waves travel at fast speeds in straight lines, eventually they will run into something. Sometimes they run into things. Sometimes they run into other waves.
1. Reflection If a wave strikes an object and bounces off, we say that it has reflected.
Law of Reflection The angle of incidence is always equal to the angle of reflection.
Law of Reflection The law holds true even if the reflective surface is not flat.
Reflection An image formed in a concave or convex mirror is distorted, but the angles of incidence and reflection are always equal. (Think about your image in a fun-house mirror!)
2. Refraction If a wave strikes an object and passes through it, we say it has been refracted. When a wave passes from one medium into another, its speed changes. When a wave s speed changes, it changes direction as well. When a wave is slowed, it bends toward the normal line. When a wave speeds up, it bends away from the normal line.
Refraction Different media cause waves to bend different amounts. The amount that a medium bends waves passing through it is called its index of refraction.
Refraction This pencil appears to be bent because light traveling from the pencil to your eye is bent at the surface of the water.
Refraction It is difficult to dive for coins in a pool or spear fish in a lake because the light traveling from the object to your eye is bent at the surface of the water, changing its apparent location.
Refraction Diamond has a high index of refraction. Light is bend sharply as it passes through diamond. This is why we can often see many different colors coming off of a diamond. Some light is also reflected off the surface of the diamond. This is sometimes called sparkle.
3. Absorption If a wave strikes an object and does not reflect off the surface or pass through, it is absorbed. In this case, the wave energy is converted into heat and the temperature of the object increases. Dark colors absorb more energy than light colors.
Reflection Wave bounces off an object Law of Reflection: incidence = reflection 1. incidence 2. Normal line 3. reflection 4. Incident Wave 5. Reflected Wave
Refraction Waves pass through the medium 7. Incidence When a wave slows down, it bends toward the normal line 8. Incident wave air glass surface 9. Normal line 10. refracted wave 11. Refraction
Interference 1. Constructive 2. Destructive
Interference 3. Destructive 4. Constructive