Well, I cannot speak for all kinds of alcohols, but the common ones (methanol, ethanol, and isopropyl alcohol) are a little less dense than water. All three of these have densities of about 0.79 g/cc at standard temperature and pressure, compared to 1.0 g/cc for water.
Lots of liquids are more dense than water or the three different alcohols mentioned.
Mercury is a liquid at room temperature and has a density of 13.6 times that of water (careful, mercuryís poisonous). Most metals, when melted, will be heavier than water (but may be hotter than water will tolerate), such as molten lead or steel (leadís also poisonous!).
Glycerol (or Glycerin) is more dense than water (1.26 g/cc).
One could argue that glass is a very slow-moving, viscous liquid (although it has lots of properties of a solid, like rigidity). Itís more dense than water.
Even saltwater is more dense than water. By how much depends on how much salt youíve dissolved in it.
(republished on 07/25/06)