Experiments to try:

http://www.spartechsoftware.com/reeko/Experiments/ExpDensityLiquids.htm

Story of Archimedes:

http://www.crsep.org/PerplexingPairs/StoryofArchimedesPart1.pdf

http://pzweb.harvard.edu/ucp/curriculum/density/s2_resources_archimedes.pdf

The Golden Crown

http://www.cs.drexel.edu/~crorres/Archimedes/Crown/CrownIntro.html

Here are some videos/tutorials on Density and its related topics:

WebQuest

http://www.aacps.org/aacps/boe/instr/curr/comed/mswebquest/densitydilemma/index.htm

Density of Gold

http://www.elmhurst.edu/~chm/vchembook/125Adensitygold.html

http://www.wikihow.com/Tell-if-Gold-Is-Real

http://www.visionlearning.com/library/module_viewer.php?mid=37

http://www.youtube.com/watch?v=ETCTK-XPKv0

The Case of the Compromised Crown

http://www.youtube.com/watch?v=XqhPjL6dsiI&feature=related

http://www.youtube.com/watch?v=oWUFnz8LDjc

Density Practice Quiz:

http://algebralab.net/practice/practice.aspx?file=Word_Density.xml