askscience

Title	Upvotes	Mark as read	Favorited	Rating	Add to a list
Why are Archaea so hard to cultivate in the lab?	9
first derivative of a curve equal to 0 indicates a minimum or maximum point. Second derivative equal to zero indicates a point of inflection. Does the third derivative being zero mean something as well?	6
My external hard drive comes with a warning not to store it at pressure of below 0.5 atmospheres. I understand that a cushion of air is needed in operation, but why would low pressure cause problems for just storage?	4
Given an operation that tells you the number of digits in a number in base-10, how many times would you have to iterate that operation on Graham's number to get a number that can fit in the Universe? Or is THAT number too big to fit as well?	2
Is it possible to make lead-acid batteries using an acid that isn't Sulfuric Acid? If so, how well would they perform?	2
If I put superheated graphite poweder (basically carbon) into a jar of pure hydrogen, what (if any) hydrocarbons would get created?	1
If I have an object of air resistance X propelled with constant speed V through a gas of ambient temperature T and pressure V, it will be heated by friction and cooled by convection. Can the equilibrium temperature of the object be calculated?	1
If I put an infrared antenna, hooked up to a battery, inside an ideal, perfectly-insulated black body, would it generate power and reduce the temperate inside due to IR radiation being absorbed? (If so, why doesn't that violate the 2nd law of thermodynamics?)	1
How come the yellow edges of a flame are so clearly defined? I understand that the yellow color is actually just the glow of heated carbon, but shouldn't that cause it to gradually taper off through dark red first?	1
What are the main design differences between a coal-burning steam engine and a wood-burning one?	1

« < > »