Calcium oxylate crystals through scanning electron microscope.
kmthu said: What's the "DO NOT EAT" thing in packaged foods, what's in it and how does it work? Thanks!
It’s silica gel…an artifical form of silicon dioxide (the same stuff that makes up sand) that has tons of tiny pores that have affinities for water. Silica gel can absorb around 40% of its weight in water. It’s manufactured to be entirely dry and then placed in food or other products that manufacturers don’t want to get moist in humid climates (slightly moist chips are what we in the real world call “stale.”) Water would rather be in the silica matrix than the food matrix, so that’s where it goes, keeping the food nice and dry.
And if you’re wondering why you shouldn’t eat it…it’s just because it’s not technically food. It’s not dangerous though…it’s just fancy sand.
Hank, you adorable dork <3 :)
We made this animation for our December 2013 advent calendar - a journey through our chromosomes in 24 short films.
Watch the whole series here.
Inside the Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, technicians dressed in clean-room suits have installed a back shell tile panel onto the Orion crew module and are checking the fit next to the middle back shell tile panel. Preparations are underway for Exploration Flight Test-1, or EFT-1.
Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities. The first unpiloted test flight of the Orion is scheduled to launch later this year atop a Delta IV rocket from Cape Canaveral Air Force Station in Florida to an altitude of 3,600 miles above the Earth’s surface. The two-orbit, four-hour flight test will help engineers evaluate the systems critical to crew safety including the heat shield, parachute system and launch abort system.
dubster said: Dear sci show why heavy metals (Led, Mercury) are harmful to humans while lighter ones like iron and magnesium are beneficial?
"Heavy metals" is more of a colloquial term than a scientific one. There are lots of very heavy metals that aren’t dangerous at all. We wear gold and silver and platinum in our jewelry. Bismuth is all up in your PeptoBismol and most of the lanthanides and actinides are safe. Also, lots of the lighter metals (particularly sodium and lithium) while being great in certain chemical forms, in their pure forms will kill you extremely quickly (and violently.)
What it comes down to is simply whether the metal interferes with the normal functioning of your body. And we’ve got complicated bodily chemistries so it turns out that there are around a dozen metals that you don’t want to get in your body. At the same time, some of them, like zinc, are helpful it certain chemical configurations. A great example of how it’s not about the metal so much as the chemistry of the body…copper is safe for humans, but is extremely toxic to fish.