Students will, given the definitions of the angles of incidence and reflection,
establish the relationship between the two angles for reflection from a planar
surface.
Students will find the relationship between the angle of two plane mirrors
and the number of whole images observed therein.
7.2 Refraction
Students will establish a qualitative relationship between the convexity
of a lens and its focal length.
Students will, using a parallel light source and a semi-circular Petri
dish filled with water, determine the approximate relationship between the
angle of incidence and refraction (an approximation of Snell’s law)
for angles of incidence less than 45 degrees.
Students will, using a parallel light source and a semi-circular Petri
dish filled with water, determine the exact relationship between the angle
of incidence and refraction (Snell’s law) for all angles of incidence.
Students will use Snell’s law to determine the index of refraction
of various media.
7.3 Interference and Diffraction
Students will, using single slits of known width and a laser whose wavelength
is known, determine the relationship between the amount of diffraction and
slit width.
Students will, using both single and double slits and a laser, distinguish
the visual phenomena known as diffraction and interference.
Students will, using a laser and double slit, determine the wavelength
of a laser beam.
7.4 Polarization
Students will establish the relationship between angle between polarization
planes and the fraction of incident radiation passing through both polarizer
and analyzer (e.g., the so called Malus’ law, I = Io*cos2Q) Hints for
teacher: 1) students should be told to work in radians because graphing programs
usually work in radians and this will reduce the confusion of having to convert
later, and 2) when the raw function is plotted I on the y-axis and Q on the
x-axis it looks like a cosine function; plot I versus cos(Q); the function
then turns out to be parabolic; plot cos(Q) to a power to linearize data (e.g.,
f(x)=A*cos(B*Q)C).
Students will, using discrete light source, a sheet of glass, and appropriate
filters, to determine the effect of angle of incidence on polarization and
determine Brewster’s angle.
7.5 Optics
Students will establish the optical principles evident through the study
of pinhole projection (e.g., relationship between object distance and image
height, pinhole distance and image height, image inversion, etc.)
Students will explain, via the construction of a geometric model, how pinhole
projection results in inverted images, and the other relationships established
above.
Student will, using pinhole camera and measurements, determine the relationships
between image height, object height, image distance, object distance, etc.
Students will, using a sperical mirror and pins to represent optical rays,
work out the paths of radiation travelling parallel to the optical axis of
the mirror, through its focus, and through its geometric radius.
Students will, employing an optical bench, establish a relationship between
object distance, image distance, and focal length of a lens (thin lens formula).
Students will solve the following compound lens problem: An identical pair
of 20-cm lenses when in direct contact give an effective focal length of 10
cm. Write an equation that would account for this. [1/10 = 1/20 + 1/20]. A
pair of 20-cm and 5-cm lenses when in direct contact give an effective focal
length of 4 cm. Write an equation that would account for this. [1/4 = 1/5
- 1/20]. Are these equations the same? Should they be the same? Why or why
not? If not, why not? Rethink the problem and come up with a new formulation.
Hint: If your new formulation is correct, you should find that 10-cm and 20-cm
lens in combintation give a combined focal length of 3.33 centimeters.
Students will work out dissipation laws dealing with point sources of light
(e.g. apparent brightness proportional to 1/r^2), columnar sources of light
(e.g., apparent brightness proportional to 1/r), and planar sources of light
(e.g. apparent brightness independent of r).
7.6 Color
Students will, using primary color projectors, work out the additive properties
of light known and define the complementary colors for each of the prinary
colors.
Students will, using cyan, magenta, and yellow filters and an overhead
projector, work out the absorption properties of filters and predict what
combinations of filters will produce.
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