Collected HW - RA 11.1
A vibration is a movement back in forth in time. A wave is a wiggle in both space and time.
Reviewed transverse and longitudinal waves, including wavelength and amplitude, in preparation for the Show Me A Wave Lab. Showed transverse and longitudinal waves with slinky.
Demo with slinky:
High frequency = high energy = short wavelength
Low frequency = low energy = long lazy wavelength
For some waves, including slinky waves, higher amplitude means higher energy.
Belly dancing tuning fork showed sound waves are caused by vibration of tuning fork
Oscilloscope showed that low frequency waves have long wavelength and for sound, low pitch. High frequency sound waves have short wavelengths and for sound high pitch.
Demo with singing rods. Hold in middle to create a node (point of no vibration). Wavelength is twice rod length. Long rod means long wavelength which gives a low pitch sound, low frequency. Short rod means short wavelength which gives a high frequency sound.
Students worked in groups in hallway doing the Show Me a Wave Lab.
Students had 30 min in class to work on homework sheet, RA 11.2b - due next Monday.
Main ideas: transverse vs longitudinal waves
For same wave speed, short wavelength = high frequency which with sound is high pitched. Long wavelength = low frequency which with sound is low frequency.
Students should know what is meant by amplitude, frequency, wavelength.
Sound is a longitudinal wave requiring a medium (matter). Light is transverse and does not require a medium (it can pass through the vacuum of space)
Thursday, January 31, 2008
Wednesday, January 30, 2008
Wed, Jan 30, 2008 - 4B
Hand out new Tiger Passes
Hand out notebooks - write name on cover, on inside cover write the addresses of the course blog sites, write down phone numbers of friends to contact in case of absence.
Go over final exam
Two ways to transmit energy: matter can carry energy (I can throw something at you to get your attention) or waves can carry energy (I can shout, "Hey!"). In the second case, the matter did not actually travel from me to you, only the wave disturbance in the matter moved. Energy moves in waves.
For sound waves, I speak and cause air molecules to wiggle. They hit other air molecules causing them to wiggle. This goes on until the air molecules hit your ear drums causing them to wiggle and you hear sound. If there is no air to wiggle, as in outer space, sound can't travel. Movie "Alien" - in space no one can hear you scream.
A vibration is a wiggle in time. A wave is a wiggle in time and space. Demonstrate with picture on whiteboard. Move hand up and down (vibration) then also move to side (draw wave)
Demonstrate that sound waves are caused by vibrations. Hit tuning fork, hear sound. Put ringing tuning fork in front of computer screen and see strobe effect of vibration - belly dancing tuning fork.
Two types of waves, transverse (movement of particles is perpendicular to direction of wave) and longitudinal (movement of particles is a-long the direction of the the wave). Demonstrate both with a slinky. Demonstrate transverse wave by students doing stadium wave.
Demonstrate with slinky and pictures: wavelength, frequency, energy, amplitude, peak, trough
High frequency = high energy = short wavelength (with visible light, this is violet light)
Purple tie days are high energy days.
Low frequency = long lazy wavelength = low energy (with visible light this is red light)
For sound, long wavelength = low frequency = low pitch
For sound, short wavelength = high frequency = high pitch
Demonstrate with frequency generator, oscilloscope, and speaker
Students updated notebooks for daily activities.
Handed out Reading Assignment 11.1 - due Friday, Feb 1, 2008
Hand out notebooks - write name on cover, on inside cover write the addresses of the course blog sites, write down phone numbers of friends to contact in case of absence.
Go over final exam
Two ways to transmit energy: matter can carry energy (I can throw something at you to get your attention) or waves can carry energy (I can shout, "Hey!"). In the second case, the matter did not actually travel from me to you, only the wave disturbance in the matter moved. Energy moves in waves.
For sound waves, I speak and cause air molecules to wiggle. They hit other air molecules causing them to wiggle. This goes on until the air molecules hit your ear drums causing them to wiggle and you hear sound. If there is no air to wiggle, as in outer space, sound can't travel. Movie "Alien" - in space no one can hear you scream.
A vibration is a wiggle in time. A wave is a wiggle in time and space. Demonstrate with picture on whiteboard. Move hand up and down (vibration) then also move to side (draw wave)
Demonstrate that sound waves are caused by vibrations. Hit tuning fork, hear sound. Put ringing tuning fork in front of computer screen and see strobe effect of vibration - belly dancing tuning fork.
Two types of waves, transverse (movement of particles is perpendicular to direction of wave) and longitudinal (movement of particles is a-long the direction of the the wave). Demonstrate both with a slinky. Demonstrate transverse wave by students doing stadium wave.
Demonstrate with slinky and pictures: wavelength, frequency, energy, amplitude, peak, trough
High frequency = high energy = short wavelength (with visible light, this is violet light)
Purple tie days are high energy days.
Low frequency = long lazy wavelength = low energy (with visible light this is red light)
For sound, long wavelength = low frequency = low pitch
For sound, short wavelength = high frequency = high pitch
Demonstrate with frequency generator, oscilloscope, and speaker
Students updated notebooks for daily activities.
Handed out Reading Assignment 11.1 - due Friday, Feb 1, 2008
Tuesday, January 29, 2008
Tuesday, Jan 29, 2008 Class 4A
Hand out new Tiger Passes
Hand out notebooks - write name on cover, on inside cover write the addresses of the course blog sites, write down phone numbers of friends to contact in case of absence.
Go over final exam
Watch first part of Bill Nye video on Waves
Energy moves in waves
Picture of wave showing wavelength and amplitude
Frequency is the number of waves that pass by each second
High frequency => short wavelength - high pitched sound
Low frequency => long wavelength - low pitched sound
Demonstrate transverse and longitudinal people waves.
Handed out Reading Assignment 11.1 - due Thursday, Jan 31, 2008
Hand out notebooks - write name on cover, on inside cover write the addresses of the course blog sites, write down phone numbers of friends to contact in case of absence.
Go over final exam
Watch first part of Bill Nye video on Waves
Energy moves in waves
Picture of wave showing wavelength and amplitude
Frequency is the number of waves that pass by each second
High frequency => short wavelength - high pitched sound
Low frequency => long wavelength - low pitched sound
Demonstrate transverse and longitudinal people waves.
Handed out Reading Assignment 11.1 - due Thursday, Jan 31, 2008
Monday, January 28, 2008
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