http://www.math.niu.edu/~rusin/uses-math/music/
A wonderful collection of links about
the interplay between
mathematics and music.
http://members.cox.net/mathmistakes/music.htm
An introduction to the work of
Pythagorus and Harmonic
scales.
http://gpn.unl.edu/guides/707.409.pdf
An engaging activity exploring the
basics of marketing and
advertising.
http://mathandecon.ncee.net/lesson.php?lid=67118&grade=35
A collection of lesson plans
incorporating basic economic
models and mathematics.
http://teacherlink.ed.usu.edu/tlresources/units/HodgesFall2005/RichardWalker/Conic%20Sections%20Webquest.pdf
An overview and collection of links that
explore the
properties of conic sections
http://www.k12.hi.us/~mathappl/MAch3Curves.html
A survey of the conic sections,
including formulas and where
to find them in nature.
http://www.shodor.org/~egrano/mathConnections/lessons/linearInequalities.html
An example
of a lesson plan about
linear inequalities
http://www.dartmouth.edu/~matc/math5.geometry/unit3/unit3.html
A history of
Pythagorus and the
Music of the Spheres.
http://www.phys.unsw.edu.au/~jw/dB.html
An introduction to the decibel, with interactive element.