Marcel finished his test on the topics of work, energy, and power. The problems required him to apply various formulas from the chapter to solve for certain variables. It was also important that Marcel provide the correct units, such as joules, seconds, or watts. He scored a 100%. There was no assignment.

After a short explanation of resonance with sound waves, a lab was performed to determine the speed of sound in air using a resonance tube, tuning forks and millimeter measurements. The lab involves inserting a resonance tube into a cylinder of water, striking a tuning fork of known frequency, holding the tuning fork over the mouth of the tube and lifting the tube and fork until the loudest sound is heard. The measurement of the air column in the tube, conversion to meters,and the frequency of the fork are used to determine the speed of sound in air.

I gave Marcel the test on work, kinetic and potential energy, and power. I allowed him to use his practice test and the textbook. He didn't finish the test so we will resume the test next session. There was no assignment.

The difference between loudness and intensity of sound was established. Loudness being subjective while intensity is objective, measurable in specific units. The intensity of different sounds was presented, and shown that a difference between a sound of 10 Db intensity and one of 20 Db intensity was not twice as intense but 10 times as intense. Using a set of tuning forks, the specific pitch produced by each one was listened to and determined that each had a specific natural frequency. It was brought out that all elastic vibrating objects have a specific natural frequency and pitch. The loudness of a single tuning fork was disturbed and noted, it was then placed base down on the table top while vibrating and the increase in loudness noted. The reason for the increase was shown to be due to forced vibrations on the table top which was a larger surface area than the tuning fork, causing more air molecules to vibrate and a louder sound.

I gave Marcel the practice test on work, energy, and power. The practice test required him to solve problems involving work, potential elastic and gravitational energy, kinetic energy, and power. Some of the problems required that he change units in the metric system. Marcel also had to apply the law of conservation of mechanical energy. There was no assignment.

The class will start by answering classwork review questions regarding last week's work. This dealt with velocity, frequency and wavelength, as well as longitudinal waves. Using a small guitar, a lab type demonstration was done to determine the effect on the pitch of a sound due to the thickness of the vibrating string as well as the length of the vibrating string. Trarefactionshe thicker the string, the lower the pitch and the lower the Hertz. As the vibrating string was made shorter, the frequency increased, the wavelength decreased and the pitch increased. The transmission of a sound wave by longitudinal waves, consisting of a series of compressions and rarefactions was shown by using a diagram of a vibrating tuning fork and the compression and expansion of the air molecules. The vibrations of the tympanic membrane in the ear, at the same frequency as the sound waves, was used to explain briefly how we hear sounds of varying pitch.

We worked several problems in which Marcel utilized the relationship between gravitational potential energy and kinetic energy. He also had to convert grams to kilograms and centimeters to meters. Marcel did a lot of the work without help which was a good sign that he understood the concepts and how to use them in word problems. There was no assignment.

The two types of waves are discussed, transverse and longitudinal. How they transmit energy, and how the particles of the wave move in relation to the wave directions... Sound waves being an example of longitudinal waves... A short video was shown which showed the compressions and refractions of this type of wave. Constructive and destructive interference with the resultant wave formed was drawn on the board. The pitch of a sound was shown to be a result of the frequency of waves, which affect the wavelengths. The higher the frequency, the shorter the wavelength and the higher the pitch. This was demonstrated using the small guitar from the music room. The Doppler effect was demonstrated and explained based on the frequency and pitch.

I gave Marcel some problems to do from the chapter review which required that he calculate power or some variable of the conservation of mechanical energy equation. He was able to do one of the problems very successfully, but needed help with a couple of the others. We also viewed a video on the physics of pole vaulting, which depends on an understanding of the law of conservation of mechanical energy. There was no assignment.

Reviewing the structure of a typical wave as designated by a sine curve, included the functions of frequency, amplitude, wave length, velocity, and wave period. A derivation of the formula Velocity = frequency x wavelength was undertaken. Once the basic formula was established, the mathematical manipulation of the formula to solve for any one of the 3 functions was shown, with examples and problems to solve. A transverse wave was presented on the board, and the definition examined, along with an example of that type of wave.