A web-based Powers of Ten. The link is http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html
Doppler shift of a car horn at 30 MPH. The link is http://www.exploratorium.com/imagery/sounds/30_MPH_doppler.au
Real Time Relativity website. The link is http://www.anu.edu.au/Physics/Savage/RTR
Phases of the Moon interactive tool. The link is http://www.calvin.edu/~lmolnar/moon/Tool.html
Topo map source allows you to find longitude, latitude, and elevation. This info can be used with the links below to find local gravity and magnetic field. The link is http://www.topozone.com
Value of g for any location. The link is http://www.ngs.noaa.gov/cgi-bin/grav_pdx.prl
Value of magnetic field at any location. The link is http://www.ngdc.noaa.gov/seg/geomag/magfield.shtml
Astronomy Picture of the Day. The link is http://antwrp.gsfc.nasa.gov/apod/astropix.html