How do we know if a thermometer is accurate? Should we trust that the local weather service has accurate thermometers? | AskScience Blog

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Sunday, February 24, 2019

How do we know if a thermometer is accurate? Should we trust that the local weather service has accurate thermometers?

How do we know if a thermometer is accurate? Should we trust that the local weather service has accurate thermometers?


How do we know if a thermometer is accurate? Should we trust that the local weather service has accurate thermometers?

Posted: 23 Feb 2019 06:40 PM PST

I was doing sone work for a real estate developer and I bought 6 (rather expensive) thermostats. All six, side-by-side had different room temperatures. They ranged from 59 degrees F to 63 degrees.

When my wife and I go to work in the morning, we each take our own cars. We both have the same make of car. My car's thermomer reads about two degrees higher than hers.

I have various thermometers around my house. Most are not cheapies. If I put them in the same room, they all have different readings. They have a 3-4 degree range.

Is there any way to know which ones are correct? Is it possible to buy an accurate thermometer that I can be confident in?

I see variations in my own thermometers. Does the local weather service do some kind of calibration to ensure accuracy? Do they have access to better thermometers that are more precise?

(I am not sure if this is the correct subreddit. If you can recommend a better ine, please feel free to make a suggestion. I don't see an r/askweightsandmeasures subreddit.)

submitted by /u/marfalump
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Why does glass (an amorphous solid) have such different characteristics than crystalline solids?

Posted: 24 Feb 2019 06:24 AM PST

Im currently reading a paper about how tardigrades use Intrinsically Disordered Proteins to survive desiccation. They argue it's due to the vitrification of the IDPs.

So I've been trying to look up and learn about why this is possible and found that glassy states aren't an "official" phase, have changes in several properties, and exist over a range of temperatures. If someone could help explain / elaborate on the properties and help point me in the correct direction I would be very grateful.

submitted by /u/N0LifeBilly
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Is cardiovascular health directly connected to your resting heart rate?

Posted: 24 Feb 2019 06:19 AM PST

So a while ago I saw a study claiming that lifting weights is as beneficial to cardiovascular health as "traditional" cardio such as running or even more beneficial. However, something I have heard quite often is that athletes who perform traditional cardio exercises regularly have a much lower resting heart rate than those who do not, because their hearts are able to move more blood per pump. Logically, this sounds as if it were very healthy. However, most people who lift weights but do not do cardio (including myself) do not seem to have a significantly lower heart rate than those who do not exercise at all. If resting heart rate and overall cardiovascular health were directly connected, lifting weights could not be as healthy as traditional cardio, or am I missing something here?

Sorry for potential spelling or grammar mistakes and thank you in advance.

submitted by /u/F4hrenheit
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Why does light diffused from laser (pointer) look grainy, but other sources look smooth?

Posted: 23 Feb 2019 05:15 PM PST

I'm a physics phd, and playing with my laser pointer today, pointing at objects that diffuse the light made me remember this question again. Why does this happen? I assume this is some coherence effect, but I can't come up with any train of thought into why all diffused light from laser pointers have the same grainy noisy effect while uncoherent light never displays this characteristic.

EDIT: Confused the words collimation and coherence

submitted by /u/sbp_reborn_again
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How does the body know to move calcium in place to grow our teeth?

Posted: 24 Feb 2019 06:24 AM PST

What is the process like? Do they grow like hair from the skin? How do they know to form incisors and molars?

submitted by /u/epanek
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What is the relationship between Neutron Stars and neutrinos?

Posted: 23 Feb 2019 02:00 PM PST

From a layman's casual Wikipedia knowledge of astrophysics, I have a few basic bits of information upon which my question is predicated.

  1. Neutron stars are almost entirely filled with neutrons with little or no empty space between them.

  2. Neutrinos fill the universe in huge numbers but due to their tiny size and lack of electromagnetism rarely interact with ordinary matter which is almost entirely empty space.

So, my understanding is then that neutrinos would hit neutron stars much more often than a celestial body made of conventional matter. There's just more there to hit.

What effects, if any, would such increased neutrino interaction have on the neutron star? Would we be able to observe or detect this change? Do the neutrinos get added to the mass of the star or are they converted into energy upon impact?

Sorry if this is a dumb question or against the rules, I don't hang around here all that often. I've just never seen anything in the popular science explaining how neutrinos relate to neutron stars.

submitted by /u/RSTLNE3MCAAV
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What is a backdoor in an encyrption algorithm?

Posted: 24 Feb 2019 05:04 AM PST

Hi,

I am referring to the NSA developed encryption algorithm SPECK. There's lots of controvery around it, although the algorithm is open source and can be implemented by anyoone who's got the skills for that.

People are suspicious about the NSA engineering backdoors into SPECK. I wonder how that is possible? Everyone can implement their own encryption software.

What does backdoor in this regard mean? Is it possible to crack an encrypted data block without the key by changing properties or by analysing the encrypted bytes?

submitted by /u/nigol313
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Microwave magnetrons, how fast is the rise/fall time and what is a practical cycle length?

Posted: 24 Feb 2019 03:48 AM PST

My microwave at home has a cycle length of 60 seconds, which seems very long. Ie on 50% power it is on for 30s then off for 30s. What necessitates such a long cycle?

submitted by /u/nicktohzyu
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How is radiation "contagious"?

Posted: 24 Feb 2019 02:17 AM PST

I'v been playing a post apocalyptic game and it got me thinking: whether nuclear reactor or nuclear weapon the amount of fissile material is relatively small but it can contaminate a large area. Can exposing inert matter to intense radiation cause it to become radioactive in turn? Sort of charging it, like heating it so after the source is removed it's still hot still emitting? How does this work on an atomic level? I mean you subject matter to energy it gets hot, or emits photons, what makes it emit A,B,G particles? If no what does it mean for an object to be irradiated: are all objects in an effected area like Fukushima covered with some residue of the original reactor fuel and that makes them dangerous?

Thanks

submitted by /u/Scourge31
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Do electrons have 'volume' or is it acceptable to view them as points in spacetime with an attributed mass?

Posted: 24 Feb 2019 05:41 AM PST

What makes an organ donor and a recipient compatible?

Posted: 24 Feb 2019 05:57 AM PST

Why are some people's organs compatible with others? Why are some rejected?

submitted by /u/Aimdoggo
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Does the colour of a vegetable and fruit depend on vitamins of it?

Posted: 24 Feb 2019 03:39 AM PST

Or if they don't, what molecules influence the colour?

submitted by /u/noveskeren
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How do scientists determine what neurotransmitters certain medications affect in the brain?

Posted: 24 Feb 2019 03:42 AM PST

There are lot's of medications that influence brain neurotransmitters such as dopamine/noradrenaline/serotonin re-uptake inhibitors. How is it actually determined what neurotransmitters are effected by these medications? Is it feasible to actually measure the concentrations of these neurotransmitters in the brain?

submitted by /u/Eindhaas
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When a mirror reflects light, can it be defined as having "total internal reflection"?

Posted: 24 Feb 2019 02:45 AM PST

If UVB rays can't penetrate glass then how does a UVB bulb emit UVB light?

Posted: 23 Feb 2019 11:36 AM PST

How exactly does retro-reflective tape work? More specifically, what differentiates relfective tape from something like duct tape?

Posted: 23 Feb 2019 06:15 PM PST

What exactly is happening when someone uses skin lotion/moisturizer?

Posted: 23 Feb 2019 08:34 AM PST

I guess I'm asking how skin cells interact with the chemicals in the lotion and where those chemicals go once they're "absorbed".

submitted by /u/AuhsojSivart
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Does relativistic effects appear when a system possesses too much potential energy? If so, what happens?

Posted: 23 Feb 2019 05:46 PM PST

Have chlorinated municipal water supplies affected beneficial bacteria in the human digestive system?

Posted: 23 Feb 2019 07:33 PM PST

  • Has the (relatively recent) use of chlorinated drinking water affected the gut flora of human populations?

  • Is it killing good bacteria in the water supply that people evolved to ingest and benefit from? Are we "missing out" on good bacteria because of this?

  • Is drinking chlorinated water actively killing bacteria within our gut or is it much too diluted at that point?

A quick online search yielded just some hippy-dippy blogs on the subject with a bunch of water filter ads that promise to remove chlorine. Sigh.

I am not against chlorination and of course recognize how critically important it is. I'm just curious as to how it may be affecting us long term. Thanks!

submitted by /u/Jules6146
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Why do prototype fusion reactors use electromagnets instead of permanent magnets for plasma containment?

Posted: 23 Feb 2019 09:57 PM PST

Does stubbornness = better problem solving?

Posted: 23 Feb 2019 07:07 PM PST

Is there a correlation between a reluctance to ask for help (or asking questions), and better problem solving skill?

If so, are there any gender divides among this?

Through observation, it seems most of my engineering student peers are males- and are good problem solvers. However, it seems the female engineers, myself included seem to struggle a bit more to find a solution, given a problem. I thought this strange at first but now I'm wondering if a possible explanation for this would be that the general stereotype that "men don't ask for help" is true, and has directly led to more grit in problem solving ability as a result of having to figure it out themselves. Is there any science/ research that supports/ refutes this? I would love to know!

submitted by /u/ElAlegna
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What are the effects of gravitational time dilation at the center of the earth?

Posted: 23 Feb 2019 09:38 PM PST

I started playing around with an equation for gravitational time dilation I found here and it seems to only apply for the earths surface and beyond.

I say this because the mass between any point within the earth and the surface would not be accounted for properly.

I tried using the Newtonian equation for acceleration due to gravity to solve this problem, with the second term under the square root becoming

1 - 2gr/c2

I then tried to use values for "g" and "r" found from a figure here at physics stack exchange.

This is where my troubles truly began, as at the center of earth the theoretical acceleration due to gravity is 0m/s2 as the assumed spherically symmetric mass distribution cancels out.

This suggests that there is either no gravitational time dilation at the center of the earth, or that I'm wrong. The latter feels like the more likely of the two options.

I have a feeling that the correct answer lies somewhere else within Einstein's field equations for general relativity, and that there may be something wrong with using Newtonian acceleration due to gravity as I have.

I look forward to some experts letting me know where I went wrong in my thinking.

Please 'o' mods let this question through, I really want an answer.

submitted by /u/Ottfan1
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Do people blind from birth have any difficulty comprehending the concept of 3d space in their minds?

Posted: 23 Feb 2019 09:02 PM PST

So when I go into my head and imagine the 3d space of say, my room, I imagine it purely visually. I can't imagine myself standing in my room with any other sense.

So, with someone who has no understanding of vision, how/can they picture a 3d space like a room in their minds? Is it even possible? And, if so, what is it like to picture a 3d room in something like, sound?

submitted by /u/Master_Vicen
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