Score
Title
260
AskScience Panel of Scientists XVIII
624
AskScience AMA Series: IAmA restoration ecologist focused on restoring oysters to the NY Harbor in New York City. AMA!
969
How does sunscreen stop you from getting burnt?
2844
How are drugs like antidepressants (who’s effects aren’t immediately apparent) developed?
5494
In the last 5-10 years, there’s been tremendous efforts made by many of the first world countries to curb carbon emissions. Have we made a dent?
8
Why does the space shuttle's transonic transition end so abruptly (see linked video)?
30
How do spacewalking astronauts get rid of body heat and CO2 they generate?
3
How does a catalyst affect activation energy?
3122
Why doesn't microwave energy escape through the holes in the screen of a microwave oven?
5
Why does the United States generally have a colder climate than most of Western Europe despite being at the same lattitude, and some parts even being further south?
15
How does the mind make up a physical feeling you've never experienced before while dreaming? For example, a virgin having a wet dream or having a foot amputated?
2
How often do collisions in LEO happen?
4
Why do people start to shrink once they get past a certain age?
3
Do bees have spatial memory when foraging for food?
7
How do we know the composition of Earth's core?
3
Suppose in an X speaking country, a child is raised by 2 parents; one speaks Y language around them, the other speaks Z language. What's the science behind this kid learning to differentiate all three languages and eventually being able to speak all 3, as opposed to if they were only exposed to 1?
25
Why does alcohol kill bacteria?
22
Why is the output power greater than the input power for a microwave?
5
Why do 3 polarising filters, at certain angles, allow some light through when two are at right-angles?
0
What happens do humans blood brain barrier as we age?
5
How do plants react to opiates? If I were to, say, use fentanyl as fertilizer, would the plant die? And what about other popular types of drugs, such as coke?
9
When can you consoder a organism dead?
2
Is chemical rocket exhaust usually a plasma?
12
Does hydraulic fracturing contribute to increased seismic activity(earthquakes) and how likely is it for the mix of chemicals+water ,that are used to displace the shale, to contaminate wells and body’s of water?
7
Why do car wheels look like they're rolling backward when moving fast?
4
Does everything rotate in space? If so, why?
2
Why don't lakes with streams flowing into other lakes eventually completely drain into the other lake?
9
Do animals have a really good sense of time or is it confirmation bias by humans?
10
What is the difference between an imaginary friend and a hallucination? What about Tulpas?
4
Where do scientists come up with temporal timelines for dinosaurs?
4987
This may be a stupid question, but what defines GMO. Is it simply changing a plant through cross pollinating (at its simplest level) such as Mendel, or does GMO mean laboratory tested and genetically altered through a laboratory?
14
What defines an “oil”?
136
Why is an Alpha particle denoted as a Helium atom?
0
When you pull at a slinky from the top, why does the bottom take a second to go with it?
3
a spider learns to build a net from other spiders or is it instinct ?
6
Why do molecules interact with others when they both have 8 valence electrons?
5
Is it more energy efficient to put cold water in a kettle, or hot water?
8
Do the planets in our solar system all orbit the sun on the same plane?
1
Which regions of the brain show diminished cell count with aging?
8
If Radiation is cumulative in our body, is Bluetooth (even with BLE) harmful to humans if we are constantly exposed to it with cellphones, smartwatch, etc. and also from other's electronic devices around us?
0
Can you feel the cold in space?
188
Are there any "weird" uses for heavy/transuranic elements?
2840 Tenthyr Strictly speaking, we CAN use most nuclear waste. Breeder reactors can be used to consume pretty much all usable fissle materials and produce a much lower volume of equivalent waste with different properties. Breeder reactors can be used to manufacture weapons grade fissile material though, so there's political aspects, as well as economic ones-- uranium is fairly abundant. Edit: spelling errors.
12552 restricteddata Radioactivity, by itself, is not that useful for generating power. What is useful for generating power is the induced splitting of _lots_ of atoms at the same time, not the slow trickle of energy release you get from radioactive decay alone. To put it another way: nuclear reactors don't work because their fuel is radioactive, they work because their fuel is splittable by neutrons. Those are not the same thing (all fuel splittable by neutrons is radioactive, but not all radioactive atoms are splittable by neutrons).
142 eestileib Check out "Reprocessing"; it's the step we removed from the current nuclear power cycle, and a major reason why our nuclear waste is so hard to store. Basically you take the used fuel rods and extract the parts that can be reused in reactors as fuel, separate the super-highly radioactive stuff that can't be used in a reactor for short term storage, and then you're left mostly with stuff that's more dangerous from heavy metal poisoning than the radiation (U-238 eg). It was stopped in the us by president Carter because of concerns about nuclear proliferation; I guess he thought we'd be clever enough to figure out how to safely store nuclear waste without a reprocessing industry, but so far we haven't, which is why we have spent fuel rods piling up.
426 pjokinen It is very usable, just not in our current nuclear reactors. Uranium fuel rods are pellets of uranium held together by a metal casing. Being inside a reactor causes the metal to become brittle, and the life of the fuel rod is determined by the life of that casing. In other reactor designs, like molten salt reactors, this casing is not used. The fuel stays in the reactor for much longer and much more of the potential energy is extracted. This results in lower volumes of waste that is much less radioactive for much less time than that coming from traditional reactors. Learn more about molten salt reactors [here](https://en.m.wikipedia.org/wiki/Molten_salt_reactor). They’re pretty awesome!
67 spasticanomaly Nuclear fuel becomes “waste” when it no longer produces enough neutrons to sustain a nuclear chain reaction. The kinetic energy of fission fragments from neutron interactions (aka fission) drives the heat cycle that produces power. The gamma and beta radiation produced by decay of “waste” isotopes contribute very little.
158 BoneyBadboyDupree American scientists developed a nuclear reprocessing system called PUREX (Plutonium-Uranium Extraction) to resume spent nuclear fuel rods. But Ford suspended it and Carter ended it permanently because of the plutonium by-product and the Non-Proliferation Agreements. Now France reprocesses many nation's fuel for reuse using this 50 year old technology.
23 Char-Lez There are lots of things classed as “nuclear waste”. Some of those things can be used as fuel, or for other purposes. The devil is in the details. Which materials? Used for what? At what cost? Etc. Most reactors are metal reactors and using these materials is either technically infeasible or economically infeasible. But Liquid Fluoride Thorium Reactors (LFTRs) can use many nuclear waste materials as fuel. They are an interesting technology I expect to see make an impact in the coming years. EDIT: spelling
34 SLUnatic85 A lot of good answers here. But also in the US, there are actually laws in place that hinder our ability to even push for nuclear fuel recycling technologies. It's mostly dueto the Ford/Carter fear of fissile by-products and the cold war as some have pointed out. My company, in France, is all about pushing for recycling their waste. That said, you need the right products left to split for heat production to make energy worth the effort. It's not about that they give off radiation, so this will only help so much. TBH it is a conversation I would LOVE to see more of though as it is a real way we can promote the energy and make it a bit safer considering how much the world is relying on it while fearing it lately.
74 Stinnett In a nuclear reactor, energy is released via fission. Some nuclides, such as U-235, are fissile, meaning they can easily undergo fission. Other nuclides, like U-238, are fertile; this means they can be converted to a fissile material by absorbing neutrons. Nuclear waste consists of many different nuclides. There is some uranium left in the waste, and it is possible to reprocess the spent fuel to retrieve it. This is pretty expensive, and the US doesn't currently do this. Many of the other components of nuclear waste (Cs-137, Sr-90, ...) are not fissile or fertile, so they aren't useful for generating nuclear power even though they are still highly radioactive.
2843 0 Tenthyr Strictly speaking, we CAN use most nuclear waste. Breeder reactors can be used to consume pretty much all usable fissle materials and produce a much lower volume of equivalent waste with different properties. Breeder reactors can be used to manufacture weapons grade fissile material though, so there's political aspects, as well as economic ones-- uranium is fairly abundant. Edit: spelling errors.
12557 0 restricteddata Radioactivity, by itself, is not that useful for generating power. What is useful for generating power is the induced splitting of _lots_ of atoms at the same time, not the slow trickle of energy release you get from radioactive decay alone. To put it another way: nuclear reactors don't work because their fuel is radioactive, they work because their fuel is splittable by neutrons. Those are not the same thing (all fuel splittable by neutrons is radioactive, but not all radioactive atoms are splittable by neutrons).
139 0 eestileib Check out "Reprocessing"; it's the step we removed from the current nuclear power cycle, and a major reason why our nuclear waste is so hard to store. Basically you take the used fuel rods and extract the parts that can be reused in reactors as fuel, separate the super-highly radioactive stuff that can't be used in a reactor for short term storage, and then you're left mostly with stuff that's more dangerous from heavy metal poisoning than the radiation (U-238 eg). It was stopped in the us by president Carter because of concerns about nuclear proliferation; I guess he thought we'd be clever enough to figure out how to safely store nuclear waste without a reprocessing industry, but so far we haven't, which is why we have spent fuel rods piling up.
421 0 pjokinen It is very usable, just not in our current nuclear reactors. Uranium fuel rods are pellets of uranium held together by a metal casing. Being inside a reactor causes the metal to become brittle, and the life of the fuel rod is determined by the life of that casing. In other reactor designs, like molten salt reactors, this casing is not used. The fuel stays in the reactor for much longer and much more of the potential energy is extracted. This results in lower volumes of waste that is much less radioactive for much less time than that coming from traditional reactors. Learn more about molten salt reactors [here](https://en.m.wikipedia.org/wiki/Molten_salt_reactor). They’re pretty awesome!
65 0 spasticanomaly Nuclear fuel becomes “waste” when it no longer produces enough neutrons to sustain a nuclear chain reaction. The kinetic energy of fission fragments from neutron interactions (aka fission) drives the heat cycle that produces power. The gamma and beta radiation produced by decay of “waste” isotopes contribute very little.
155 0 BoneyBadboyDupree American scientists developed a nuclear reprocessing system called PUREX (Plutonium-Uranium Extraction) to resume spent nuclear fuel rods. But Ford suspended it and Carter ended it permanently because of the plutonium by-product and the Non-Proliferation Agreements. Now France reprocesses many nation's fuel for reuse using this 50 year old technology.
23 0 Char-Lez There are lots of things classed as “nuclear waste”. Some of those things can be used as fuel, or for other purposes. The devil is in the details. Which materials? Used for what? At what cost? Etc. Most reactors are metal reactors and using these materials is either technically infeasible or economically infeasible. But Liquid Fluoride Thorium Reactors (LFTRs) can use many nuclear waste materials as fuel. They are an interesting technology I expect to see make an impact in the coming years. EDIT: spelling
38 0 SLUnatic85 A lot of good answers here. But also in the US, there are actually laws in place that hinder our ability to even push for nuclear fuel recycling technologies. It's mostly dueto the Ford/Carter fear of fissile by-products and the cold war as some have pointed out. My company, in France, is all about pushing for recycling their waste. That said, you need the right products left to split for heat production to make energy worth the effort. It's not about that they give off radiation, so this will only help so much. TBH it is a conversation I would LOVE to see more of though as it is a real way we can promote the energy and make it a bit safer considering how much the world is relying on it while fearing it lately.
73 0 Stinnett In a nuclear reactor, energy is released via fission. Some nuclides, such as U-235, are fissile, meaning they can easily undergo fission. Other nuclides, like U-238, are fertile; this means they can be converted to a fissile material by absorbing neutrons. Nuclear waste consists of many different nuclides. There is some uranium left in the waste, and it is possible to reprocess the spent fuel to retrieve it. This is pretty expensive, and the US doesn't currently do this. Many of the other components of nuclear waste (Cs-137, Sr-90, ...) are not fissile or fertile, so they aren't useful for generating nuclear power even though they are still highly radioactive.