Global windstorm -- Relativistic baseball -- Spent fuel pool -- Weird (and worrying) questions from the What if? inbox, #1 -- New York-style time machine -- Soul mates -- Laser pointer -- Periodical wall of the elements -- Everybody jump -- A mole of moles -- Hair dryer -- Weird (and worrying) questions from the What if? inbox, #2 -- The last human light -- Machine-gun jetpack -- Rising steadily -- Weird (and worrying) questions from the What if? inbox, #3 -- Orbital submarine -- Short-answer section -- Lightning -- Weird (and worrying) questions from the What if? inbox, #4 -- Human computer -- Little planet -- Steak drop -- Hockey puck -- Common cold -- Glass half empty -- Weird (and worrying) questions from the What if? inbox, #5 -- Alien astronomers -- No more DNA -- Interplanetary Cessna -- Weird (and worrying) questions from the What if? inbox, #6 -- Yoda -- Flyover states -- Falling with helium -- Everybody out -- Weird (and worrying) questions from the What if? inbox, #7 -- Self-fertilization -- High throw -- Lethal neutrinos -- Weird (and worrying) questions from the What if? inbox, #8 -- Speed bump -- Lost immortals -- Orbital speed -- FedEx bandwidth -- Free fall -- Weird (and worrying) questions from the What if? inbox, #9 -- Sparta -- Drain the oceans -- Drain the oceans : part II -- Twitter -- Lego bridge -- Longest sunset -- Random sneeze call -- Weird (and worrying) questions from the What if? inbox, #10 -- Expanding Earth -- Weightless arrow -- Sunless Earth -- Updating a printed Wikipedia -- Facebook of the dead -- Sunset on the British Empire -- Stirring tea -- All the lightning -- Loneliest human -- Weird (and worrying) questions from the What if? inbox, #11 -- Raindrop -- SAT guessing -- Neutron bullet -- Weird (and worrying) questions from the What if? inbox, #12 -- Richter 15.