data. For example, if we have two angles of 2° and 358° marked on a
360° circle, they are nearly identical (both are near 0°). However, if
we calculate a traditional (or arithmetic) mean, one would mistak-
enly report it to be2þ358 2 ¼ 180°. This would point in the entirely
opposite direction! By using geometry, we can actually calculate
the circular mean correctly as 0° (for more information, see the
Online Materials). The handout (Appendix) provides an additional
example that uses simple math that students can work by hand to
illustrate how using linear statistics, for example calculating a mean,
is incorrect when applied to circular data.
Part 3: Construct the Pulse Magnetizer
The pulse magnetizer circuit consists of a 9-volt battery, a switch,
and a coil (Figure 1A, B and Figure 2A). Alternatively, a 470 Ω
resistor and light-emitting diode (LED) can be added in parallel with the
coil to illuminate when the switch is pressed (Figure 1C). The coil is
Table 2. AP Biology and AP Physics 2 topics relevant to our lesson plan.
Enduring Understanding Essential Knowledge Relation to Our Lesson Plan
Many biological processes involved in
growth, reproduction and dynamic
homeostasis include temporal regulation
Timing and coordination of behavior are
also regulated by several means;
individuals can act on information and
communicate it to others, and responses
to information are vital to natural
selection. . . . Examples include behaviors
in animals triggered by environmental
Students learn about animal behavior,
specifically how to observe and quantify
it, the factors that confound studies of
animal behavior, and how behavior can
vary between individuals. They also
learn about how information in the
form of magnetic fields can influence
For cells to function in a biological
system, they must communicate with
other cells and respond to their external
Signal transduction pathways link signal
reception with cellular response.
Students learn about the cellular basis
of magnetoreception and receive an
introduction to this unfamiliar sensory
Organ systems have evolved that sense
and process external information. . . .
These include sensory systems that
monitor and detect physical and chemical
signals from the environment. . . . The
nervous system interacts with sensory and
internal body systems to coordinate
responses and behaviors.
Animals have nervous systems that detect
external and internal signals, transmit
and integrate information, and produce
Students learn about magnetoreception
in general, its potential functions as a
navigation guide, and how animals with
a magnetic sense can detect external
signals and initiate a behavioral
An electric field is caused by an object
with an electric charge.
The student is able to distinguish the
characteristics that differ between
monopole field . . . and dipole fields
(electric dipole field and magnetic field)
and make claims about the spatial
behavior of the field.
Students in our lesson plan learn about
the relationship between magnetic and
electric fields and gain hands-on
experience creating a device that exerts
an electric (and magnetic) field.
A magnetic field is caused by a magnet
or a moving electrically charged object.
Magnetic fields observed in nature always
seem to be produced either by moving
charged objects or by magnetic dipoles or
combinations of dipoles.
The student is able to describe the
orientation of a magnetic dipole placed
in a magnetic field in general and the
particular case of a compass in the
magnetic field of the Earth.
Students learn about Earth’s magnetic
field, conduct an activity that involves
finding magnetic north on a compass,
and are able to observe how the
compass needle changes in response to
an artificial electromagnetic field.
Electric charge is a property of an object
or system that affects its interactions with
other objects or systems containing
Electric charge is conserved. An electrical
current is a movement of charge through
Students gain hands-on experience
building a coil that carries electric