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?
222 nogreatshakes Yes, they are constantly vibrating, but are a lot more constrained than in fluids. For a real “solid” solid like a metal or crystalline substance the atoms or molecules have to keep their lattice structure, so there isn’t free movement throughout the solid, but they are constantly oscillating about their average position. If this weren’t the case, solids would be at absolute zero all the time.
20 -DreamMaster As mentioned before, particles in a solid are in fact moving. You can "observe" that with gauge blocks. The faces of these blocks are so flat, that they stick together if you stick them together in a certain way. ([Here](https://www.youtube.com/watch?v=2lOOl3VxOtE) is a nice video about that). However, if you "stick" two of those together and leave them for a few weeks/month/years (depends on the temperature) they actually weld together. Since a good set of gauge blocks is expensive as hell, be sure to always put them away separated from each other. EDIT: formatting and typo
10 bobide Yes, diffusion occurs in solids as well. Atoms can move through the crystalline lattice of a solid material through a number of different routes. The atoms can move through interstitial or substitutional mechanisms for example.
3 YoungJaaron Particles must always move, no matter what the conditions due to Heisenberg's uncertainty principle, which states one may not know the exact velocity and position of a particle. The more we know about one value, the less we know about the other. This means that no particle may be completely motionless, as we would then know the position and the velocity simultaneously. Even at absolute zero, particles still move, even if it's the slightest movement. I believe Feynman called it the "quantum jitters," but the technical name for this phenomenon is "zero point motion." So yes, particles must move in a solid. To answer your second question, atoms are so attracted to each other that they vibrate, but don't move past each other. Atoms in liquids move much more freely amongst each other.
2 radicallyhip Basically the reason why substances in gaseous and liquid states flow and move around is they have enough kinetic energy (per particle) to resist the inter-particular forces (dipole bonding, hydrogen bonding etc). When they have this amount of kinetic energy behind them, if they bump into another particle, the momentum continues to carry them along and they overcome the sticky bonding forces. However, as we cool a gas down, and it condenses into a liquid, we see particles having more interactions; their volume decreases because the particles have less energy, and they interact with the attractive forces of other particles more. Not enough to make them stick, but enough to contain them in a definite volume at a constant pressure. They still flow and hold the shape of their container but they do not expand to fit the whole thing. If we continue to cool this substance below the fusion/freezing point, the kinetic energy of the particles ceases to carry enough momentum to overcome the sticking forces of other particles. H-bonding, ionic crystallization or induced dipole-dipole interactions, etc all occur at this point, and the substance becomes rigid - the particles are more strongly attracted to one another and the particles are no longer free to move about. They become stuck in place as interactions occur between more and more particles. They still vibrate in place, but do not have enough energy to break free from those bonds formed within their network of bonds.
1 Puteh The movements of atomic nuclei in solids can be measured to quite high precision using techniques such as X-ray absorption fine structure. These techniques determine the spatial distribution of internuclear distances between pairs of atoms. A typical deviation from the mean separation of ca. 0.3 nm would be 0.01 nm at room temperature. Reference (not for the fainthearted): https://pdfs.semanticscholar.org/de39/973536b1c4120fccb6b2892b7d14fddbd7c0.pdf
228 0 nogreatshakes Yes, they are constantly vibrating, but are a lot more constrained than in fluids. For a real “solid” solid like a metal or crystalline substance the atoms or molecules have to keep their lattice structure, so there isn’t free movement throughout the solid, but they are constantly oscillating about their average position. If this weren’t the case, solids would be at absolute zero all the time.
21 0 -DreamMaster As mentioned before, particles in a solid are in fact moving. You can "observe" that with gauge blocks. The faces of these blocks are so flat, that they stick together if you stick them together in a certain way. ([Here](https://www.youtube.com/watch?v=2lOOl3VxOtE) is a nice video about that). However, if you "stick" two of those together and leave them for a few weeks/month/years (depends on the temperature) they actually weld together. Since a good set of gauge blocks is expensive as hell, be sure to always put them away separated from each other. EDIT: formatting and typo
9 0 bobide Yes, diffusion occurs in solids as well. Atoms can move through the crystalline lattice of a solid material through a number of different routes. The atoms can move through interstitial or substitutional mechanisms for example.
6 0 YoungJaaron Particles must always move, no matter what the conditions due to Heisenberg's uncertainty principle, which states one may not know the exact velocity and position of a particle. The more we know about one value, the less we know about the other. This means that no particle may be completely motionless, as we would then know the position and the velocity simultaneously. Even at absolute zero, particles still move, even if it's the slightest movement. I believe Feynman called it the "quantum jitters," but the technical name for this phenomenon is "zero point motion." So yes, particles must move in a solid. To answer your second question, atoms are so attracted to each other that they vibrate, but don't move past each other. Atoms in liquids move much more freely amongst each other.
2 0 radicallyhip Basically the reason why substances in gaseous and liquid states flow and move around is they have enough kinetic energy (per particle) to resist the inter-particular forces (dipole bonding, hydrogen bonding etc). When they have this amount of kinetic energy behind them, if they bump into another particle, the momentum continues to carry them along and they overcome the sticky bonding forces. However, as we cool a gas down, and it condenses into a liquid, we see particles having more interactions; their volume decreases because the particles have less energy, and they interact with the attractive forces of other particles more. Not enough to make them stick, but enough to contain them in a definite volume at a constant pressure. They still flow and hold the shape of their container but they do not expand to fit the whole thing. If we continue to cool this substance below the fusion/freezing point, the kinetic energy of the particles ceases to carry enough momentum to overcome the sticking forces of other particles. H-bonding, ionic crystallization or induced dipole-dipole interactions, etc all occur at this point, and the substance becomes rigid - the particles are more strongly attracted to one another and the particles are no longer free to move about. They become stuck in place as interactions occur between more and more particles. They still vibrate in place, but do not have enough energy to break free from those bonds formed within their network of bonds.
1 0 Puteh The movements of atomic nuclei in solids can be measured to quite high precision using techniques such as X-ray absorption fine structure. These techniques determine the spatial distribution of internuclear distances between pairs of atoms. A typical deviation from the mean separation of ca. 0.3 nm would be 0.01 nm at room temperature. Reference (not for the fainthearted): https://pdfs.semanticscholar.org/de39/973536b1c4120fccb6b2892b7d14fddbd7c0.pdf