The definition of transparent, and why a substance is transparent was outlined and labeled on the board. The vibrations of electrons creating some heat in substances was shown. The inability of UV light to pass through glass was explained in terms of frequency and vibrations of electrons. The speed of light in various media was presented as well as the thought problem "why is everything we see, actually in the past".

A laser light and various transparent and opaque objects were used to describe what happens when a light wave reaches the interface between 2 media. The reflection route of a wave when it strikes a non absorbent surface, as well as when it strikes the surface between air and water was drawn and discussed. The definition of reflection was given, as was total and partial reflection. Why metals are shiny was explained in terms of absorption and reflection.

Marcel and I continued to alternate doing selected problems from the book on conservation of momentum and impulse. We focused mainly on problems where there was an inelastic collision. After I demonstrated how to write the equation to solve for the different variables involved, Marcel solved a different problem with the same basic approach and equations. I asked him to quickly solve a problem where there was a perfectly elastic collision and he was able to instantly solve the problem. There was no assignment.

The 2 types of waves produced by vibrating bodies was discussed and that sound is a longitudinal wave. The direction of the movement of molecules which occur in a transverse wave as well as a longitudinal wave was drawn and explained.

Light from a vibrating object can be shown as rays moving in all directions from the source. Light rays moving in only one direction are polarized. Using a beam of light with 2 rays as our example, both rays at right angles to each other, a polarizing lens was shown to allow only one set of rays to exit the backside of the lens. Using a second lens at 90 degrees, the complete blockage of light was shown. The physics behind this was explained with diagrams on the board.

I reviewed the significant digit rules with Marcel and showed him a mnemonic device for remembering how to treat zeros in determining the number of significant digits in a number. Since he was not at the school when I would have worked with him on this topic, I decided it was time to work on this important topic.
After I did some examples of significant digits, I started to work a problem on conservation of momentum with Marcel. Due to our work on significant digits, we did not have time to finish the problem. I will work with him on the problem during our next session. There was no assignment.

Marcel and I alternated doing problems involving elastic collisions. I reminded him how the change of momentum must be carefully calculated by taking the direction of moving objects into consideration. We both found new velocities of objects after elastic collisions. I also showed him a video of powers of ten as a way for him to keep his perspective in problem solving. There was no assignment.

A review of some introductory material involving the production of light energy, the electromagnetic nature of light, and the need not to have a medium for transmission. Transparent and opaque objects were defined in terms of electron vibrations, re-emission of light from the other side and absence of light being re-emitted. The conversion to heat from the loss of some energy passing through the glass was shown as a function of the frequency of the electro magnetic wave. The speed of light, once re-emitted, returned normal. The speed light passing through various substances was listed.

The speed of light, the genesis of light, the frequency and vibrations of light were discussed and related to the same type of motion in sound. The resonance of a substance when exposed to a certain frequency of light energy was talked about, and how in order to cause these resonant vibrations, the vibrating object must have a very low inertia. Electrons meet this criteria.

Review quiz answers... Demonstrate a changing electric field producing a changing magnetic field, and vice versa. Relate the resonance produced by light waves to those of sound, utilizing the same physics principles. Discuss the speed of light not dependent on how it started, always the same, only the frequency and wavelength will change. Relate light waves causing vibrations in a substance, but only if the substance has low inertia.