Question of the Week

1A) The refractive index of water (n) is 1.33.

Using what you've learned about how the eye focuses light, explain why everything looks blurry when we swim under water.

B) What animals need to see above and below the water? How might they do that?

2) Explain the demonstration performed on the first day of class, i.e., cyan and yellow ink mixed together make green ink, but blue and yellow light mixed together make white light. (Hint: pay careful attention in lab.)

We see a carrot as orange. Is the carrot "really" orange, or is orange a mental construct of our brains? Draw on what we learned in class today.

1. Suppose V = 1.0V, and R = 2 ohm. Use Ohm's Law to calculate I in amps.

2. If you increase R and keep I constant, what happens to V?
If you increase R and keep V constant, what happens to I?

So ... what is the relationship between:
V and I
V and R
I and R?

3. Water flows out of a bathtub down a drain. What, in this process, is analogous to current, resistance, and voltage?

How do cell phone frequencies compare to the frequencies of visible light? (If necessary, you can calculate the frequencies of visible light from the wave equation: c = wavelength x frequency.) (Note: MHz = megahertz, or a million hertz.)

Draw a nerve cell as an electrical circuit with a battery and resistors. What part(s) of the nerve cell are:
the terminals of the battery, and what are the resistors? Are the resistors in series or in parallel? Get another view of an action potential here.

Compare these three phenomena: photoelectric current, battery-driven current, nerve impulse (action potential). What is the charge carrier? What does the current travel in? What supplies the energy to produce the current?

What experiments show that light is a wave?
What experiments show that light is a particle?

1) Read Ch 31, Selected Readings, and answer the following:

a) p. 249. What is hn and why is it written over the arrow in both these equations?
b) p. 250. List the similarities between photosynthesis and the photoelectric effect.
c) p. 251. What, exactly, moves along the path of the arrows in Figure 1?
d) p. 252 Cotter calls the PRC a "continuous chain of atoms." It can also be thought of as a continuous chain of molecules. What kind of molecules? How does the plant cell know how to make this chain of molecules? (Review your lecture notes from 11/15 and 11/17, Ch 19, Selected Readings, and Ch 15, 16 Science Matters.)
e) p. 252-253 and lecture 11/15 & 11/17. How is the PRC similar to rhodopsin?
f) p. 253-254, and table, p. 247. Explain why chlorophyll in solution fluoresces but chlorophyll in an intact leaf does not.

2) Plants have mitochondria and do respiration just like you do. Why should they do this in addition to photosynthesis? (See Ch 24, Selected Readings.)

1) In torus tic-tac-toe, how many fundamentally different moves are there to open?

2) How many different responses (2nd moves) are there, given the first move?

3) Can either player be guaranteed to win? (E.g., does the first player always win if the right moves are made?)