How has our understanding of Astronomy, Biology, Chemistry, etc. changed in the last five years? [more inside]
posted on Mar 24, 2008 - 15 answers

Is there a chemical explanation for the density of an element or is it simply an innate physical characteristic? [more inside]
posted on Jan 21, 2008 - 14 answers

Why do neutrons have more mass than protons? [more inside]
posted on Jan 16, 2008 - 30 answers

FirstTimeTutorFilter: I'm plan to start tutoring Math, Chemistry, Physics and possibly ESL in January. Only problem is, I have *no idea what I'm doing*. Anyone have any textbooks, general teaching books, online certification courses, etc to recommend? [more inside]
posted on Dec 17, 2007 - 8 answers

"A human is halfway in size between an atom and the known universe"... This is a paraphrased quote I have come across several times. I like it. Who said it first? How true is it in the most literal sense? And, finally, what errors arrive in postulating a universe, or an atom, which can be measured AT ALL from our singular, relativistic, perspective? [more inside]
posted on Feb 18, 2007 - 14 answers

Does household natural gas pool in low places or rise to high places? [more inside]
posted on Feb 13, 2006 - 19 answers

How could a Coke can leak its contents without any apparent holes? [more inside]
posted on Nov 23, 2005 - 25 answers

What would happen if you take a cube of ice, at a specific size, and fit it in an airthight glass box with the exact same dimensions, and then let it melt? [more inside]
posted on Jun 2, 2005 - 29 answers

Why do porous objects (wood, textile, hair, etc) appear darker when wet then when dry? A googling gave me this ("surface reflection and refraction"), but that doesn't sound entirely reasonable, as it merely talks of light being scattered, but the light in question is already diffuse. This also gives some suggestions, but nothing conclusive. Any chem/physics MeFiers know this?
posted on Dec 12, 2003 - 7 answers