Old cathode ray tube (CRT) televisions have an electron gun which fires electrons at the back of the screen. And the screen is coated with phosphors which emit light whenever struck by an electron. The side-effect of this process is that each electron increases the static charge of the screen, and over time as the image on the TV changes it increases the charge. Meanwhile, rubbing your hand, which has a slight negative charge, across the screen will remove some of this built-up static.
Saturday, 19 March 2016
Wednesday, 16 March 2016
ELI5: Why does having general anesthesia feel like you blink and you're in the recovery room when normal sleep feels like time passed?
No one really knows. Seriously we do not understand how it works. An anaesthetised unconscious state is not like sleep at all but more like a coma, though the exact details of what happens remain a mystery so far. Obviously the parts of the brain that are responsible for creating a sense of time having passed when we sleep are also prevented from working or prevented from recording it for a while.
Monday, 14 March 2016
ELI5: Why is it still so difficult to definitively determine the source of major rivers like the Nile and Yellow River?
Because hundreds of rivers merge to form these big rivers. So technically there are numerous sources. Which creek, drainage, stream or other water source is the river and which is just a feeder? Lot of options to debate there.
ELI5: What happens inside of a USB flash drive that allows it to retain the new/altered data even when it's not plugged in?
When you charge a battery it retains the charge for a long time even though it is not plugged in. Think of a flash drive like a collection of billions of microscopic tiny batteries. Some of them are charged up (and contain a “1”) and others are not (containing “0”).
ELI5: Why is growling such a common way to show aggression in the animal kingdom?
Growling in dogs isn’t a show of aggression. It is a show of unease - you’re invading its space or you represent a threat and (s)he wants you to back off.
It’s actually a sign the dog would prefer for this to not evolve into conflict.
Aggressive dogs attack without any growling.
Saturday, 12 March 2016
ELI5: Why do colleges accept students who excel in sports while having bad academic merits?
Money. College football and basketball generate a lot of money and donations from alumni. Especially if you have really wealthy alumni like T. Boone Pickens. He paid for a lot of new athletic buildings. There are lots of former college players with degrees that can barely read or write but were able to run fast with a ball. Several colleges have been busted for enrolling their athletes in phantom classes where they never had to show up and still earned A’s. My best friend’s cousin played football at a college in Texas and wouldn’t have to turn in assignments or take exams in most classes.
Thursday, 10 March 2016
ELI5: Why is marijuana "impossible" to overdose on?
Bluntly put, the median lethal dose (LD50) of THC (the active ingredient in marijuana) is so high and the methods of intake so dilute that you would have to do absolutely impossible feats to have it occur. While there are a couple of different and conflicting sources, one estimate placed it at 40,000 times as much as the dose needed to get high. This is contrasted with alcohol, where five to ten times the amounted needed to get you drunk can kill you. To extrapolate, With pot brownies you’d die of sugar poisoning long before the THC got you. With smoking, you’d have to smoke something like 1,500 pounds of weed in a period of 15 minutes.
To actually manage a THC overdose you’d have to spend a lot of effort to first purify a sizable quantity of THC and then ingest it rapidly. This would never happen accidentally.
