Recent comments in /f/askscience

Mad_Dizzle t1_jce3bfi wrote

Reply to Are eyes an example of synapomorphy or convergent evolution? by Beginning_Exam6255

As with a lot of things in evolutionary biology, the answer is probably both. Most life, from my understanding, responds to light. Whether that be to photosynthesize or to see, because the sun is the primary source of energy in our ecosystem. Eyes likely all come from a similar source that responded to light in an advantageous way. However, many eyes may have evolved separately, which could be why different animals can see different wavelengths of light.

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deevulture t1_jce2rso wrote

Reply to Are there any significant differences between odd and even numbered family sizes? by SignWonderful2068

I tried to look up if there's much information about this topic in particular. The fact that this question was the first to pop up says a lot about that in that front.

That being said, the closest you'd get would be the difference between a nuclear family with one child versus two kids and maybe three kids. A larger family of 12 or 13 an additional child or not would likely not have a significant effect. In that sense, there is research on that. Children cost money to raise, and with every additional child the costs go up exponentially, depending on other factors - access to money, food, clothing, other lifestyle factors - vacation time, travel necessities etc. would have an impact on the life of the children give or take one or 2. Lack of secure resources puts more strain on family relationships. Single children have more time devoted to them by their parents than families with more of them, but the significance of this has been disputed for the most part. Smaller families are associated with better IQ, job outcome, academic achievement than larger families, which tend to get married younger and have more kids at an earlier age. It's not exactly what you're looking for, but it might help.

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Bbrhuft t1_jcdzt3r wrote

Reply to comment by Twink_Ass_Bitch in Radon is a monatomic gas, but its decay products are solids. After a decay, what happens to the individual atoms of the daughter elements? Do they stay suspended in the atmosphere or slowly rain out? by foodtower

The radon progeny, Bi-214 and Pb-214 do not react with oxygen, except sometimes Po-218.

They start off are singly ionized ions (Po+, Pb+, Bi+). As a result, reactions with Volatile Organic Compounds (VOCs), which commonly contaminates air, especially indoor air, is favoured over oxygen. They also react with hydroxyl radicals, ionized water vapour that's formed in the ionization trail of their recoil path (Po-218 recoils at 13 million mph, after Radon-222 emits an Alpha particle travelling at 7% the speed of light).

These reactions form minute particles, 1.2 to 2 nm in diameter, likely consisting of clusters of 5 to 8 water molecules and a few molecules of VOCs surrounding a now neutral atom of Pb or Bi.

That said, some Po-218 ions react to form Po oxide. This is shown by a double peak in measured particle size distribution of radon Po progeny particles; Po forms a double peak, smaller particles of PoOx of 0.5 - 1.5 nm and much lager particles (c. 15 nm) of a Po atom surrounded by SO2, water and VOC molecules much larger than Bi-214 and Pb-214 clusters.

Castleman Jr, A.W., 1991. Consideration of the chemistry of radon progeny. Environmental science & technology, 25(4), pp.730-735.

Hopke, P., 1996. The initial atmospheric behavior of radon decay products. Journal of Radioanalytical and Nuclear Chemistry, 203(2), pp.353-375.

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Bbrhuft t1_jcdxda3 wrote

Reply to comment by hydroxypcp in Radon is a monatomic gas, but its decay products are solids. After a decay, what happens to the individual atoms of the daughter elements? Do they stay suspended in the atmosphere or slowly rain out? by foodtower

Po-218, Lead-214 and bismuth-214 are singly ionized ions. Since they are singly ionized, reactions with oxygen are not favoured, they are instead predicted to hydrolyse with hydroxyl radicals and with trace Volatile Organic Compounds (VOCs) that often contaminate air, indoor air in particular.

Also, you must consider the effects of the radiation and kinetic recoil of the ions, their velocity, c. 10-13 million mph for Po-218 ions after they emit an Alpha particles at 7% the speed of light. Lead-214 and Bismuth-214 also form in ionization trails, generated by Beta particles. As a result, chemical reactions, and thus neutralization of the ions, take place with hydroxyl radicals generated from ionized water vapour, and also, likely NO₂.

The reaction products of radon progeny grow and form ultrafine particles, 1.2 to 2 nanometres in diameter, these likely consist of 5 to 8 molecules of water and a few molecules of VOCs. These stick to dust or settle on solid surfaces, i.e. radon progeny plate out.

>The chemical and physical properties of 218Po immediately following its formation from 222Rn decay are important in determining its behavior in indoor atmospheres and play a major part in determining its potential health effects. In 88% of the decays, a singly charged, positive ion of 218Po is obtained at the end of its recoil path. > >These ions can interact with water vapor or other volatile organic compounds (VOCs) that may exist in indoor air. > >The ions can be neutralized by 3 different mechanisms, small-ion recombination, electron transfer, and electron scavenging. In typical indoor air, the ion will be rapidly neutralized by transfer of electrons from lower ionization potential gases such as NO2. > >The neutral molecule can then become incorporated in ultrafine particles formed by the radiolytic processes in the recoil path. These particles will typically be formed by the presence of the air ions produced by the passage of the emitted α-particle through ion-induced nucleation. > >In addition these energetic ions can react with water molecules to produce hydroxyl radicals. > >Thus, the decay of the radon nucleus produces a variety of effects and can result in changes in the size of the radioactive species that includes the radon progeny.

Refs.:

Castleman Jr, A.W., 1991. Consideration of the chemistry of radon progeny. Environmental science & technology, 25(4), pp.730-735.

Hopke, P., 1996. The initial atmospheric behavior of radon decay products. Journal of Radioanalytical and Nuclear Chemistry, 203(2), pp.353-375.

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mfb- t1_jcdb4p7 wrote

Reply to comment by onegumas in Radon is a monatomic gas, but its decay products are solids. After a decay, what happens to the individual atoms of the daughter elements? Do they stay suspended in the atmosphere or slowly rain out? by foodtower

A single lead atom (or ion) still moves so fast that it's going to collide with some random side of the room with almost equal probability in vacuum. If the wall has the same temperature and the atom doesn't get stuck there then it has no reason to lose kinetic energy over time, although its energy will vary randomly from each collision. In practice lead atoms tend to stick to something pretty quickly at room temperature.

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Upintheassholeoftimo t1_jcd6av5 wrote

Reply to Radon is a monatomic gas, but its decay products are solids. After a decay, what happens to the individual atoms of the daughter elements? Do they stay suspended in the atmosphere or slowly rain out? by foodtower

Consider water vapour in the form of humidity. We say water is a liquid but the liquid phase can only exist if there is enough of it in vapour phase to begin to condense out.

The same is true for lead with the difference been that it requires a lot less lead in vapour phase before it starts to condense out.

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