Questions in the Science & Nature category.
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January 18

Why aren't my contacts available for daily wear?

I wear contact lenses only occasionally, so I wanted to switch from monthlies to dailies. But it turns out they don't make a daily lens with my prescription (for astigmatism). Is there some specific reason they do not do this -- I was told they only do a 180 +/- 20, and my astigmatism is 30. But why do they stop at 20?
posted by jeather at 1:31 PM - 6 answers

January 17

Data Munge: Uknown combination of 7 numbers produces a given number.

Data Munging Pros: In a spreadsheet with ten data columns, Column "A" is related to columns "B" through "J" in that some unknown combination or interaction of some or all of them will produce the data in Column "A". How do we determine what that combination is? (I can't even find what this type of problem is called, and I've not been able to find any productive Google search terms.) A more thorough explanation/example is provided in-thread. [more inside]
posted by jjjjjjjijjjjjjj at 10:20 AM - 13 answers

January 13

Math For Spacing Out Three-Day Weekends, But Accounting for Holidays

I'm a big honkin' geek, and I would like to figure out an Excel formula I could reuse from year to year to space out my vacation day choices -- but including holidays, which would prevent even distribution. How can I still get as close as possible? More inside. [more inside]
posted by WCityMike at 3:28 PM - 10 answers

Do Mice Eat Human Semen?

Thanks to some crummy apartments I've lived in over the past few years, I've had some experiences that have led me to believe mice are attracted to/trying to eat my semen, thankfully when I am far away from it and them. Is this remotely plausible or am I galloping headlong into some weird combination of projection, pattern-matching, and narcissism? [more inside]
posted by anonymous at 11:12 AM - 11 answers

January 12

Help a kid science the speed of sound

Asking for my kid: My teenager got a science assignment to determine the speed of sound. She is planning to measure the time difference between a visual event and the accompanying sound, observed from a set distance. Can you help her find practical ways to do the experiment? [more inside]
posted by sively at 8:27 AM - 22 answers

January 9

What's the most efficient non-moving shape for collecting solar energy?

I am working on a solar water heater, and I am trying to figure out this geometry problem. I know a parabola is the most efficient movable shape to collect the sun's energy, but what is the most efficient fixed shape? It will clearly change with date and lattitude, but given an average day, what shape focus the most energy onto a heating tube? [more inside]
posted by juice boo at 7:42 PM - 6 answers

January 6

Cool picture time

What small object do you think would be interesting to see as a CT (aka CAT scan)? [more inside]
posted by tchemgrrl at 5:29 PM - 31 answers

Personal Planetarium?

I'm looking for a home planetarium that will fill a room with stars. I'd like something that projects onto the walls and ceiling, and something that's bright enough so that the stars are visible on a wall 10 feet from the device. The star themselves don't need to be correctly placed, I'm going for the feel of a stary sky rather than being able to identify specific stars and constellations. At the same time I do not want any constelation lines, planets, or really anything except the stars themselves. [more inside]
posted by Maastrictian at 11:08 AM - 12 answers

Tree ID Florida Edition

What kind of tree is this with long threads/vines coming out of the branches? What are those threads? [more inside]
posted by dearwassily at 11:07 AM - 10 answers

January 2

Distributions/Plots for Social Sciences

I'm writing a story and I need a marginally believable conversation between a professor and grad student in the social sciences discussing some data. The student is showing the prof some data analysis and ... [more inside]
posted by falsedmitri at 2:43 PM - 7 answers

January 1

I'm sleeping with my head in a 6 milliGauss AC magnetic field.

So there's a powerline outside my bedroom window, and I thought, huh. Turns out I'm sleeping with my head in a 6mG AC magnetic field. Help me use physics to stop caring. [more inside]
posted by zeek321 at 9:29 AM - 8 answers

December 30, 2016

What Malthusian catastrophe reverts to middle ages?

To be clear, what population decimation (50%, 80%?) drives our (western) world back to the middle ages, despite our accumulated/combined knowledge (and how)? Assume global event - I can't imagine one developed nation devolving unless all have
posted by b33j at 5:47 AM - 24 answers

December 29, 2016

A. Einstein mystery

Grandfather the mathematician took sabbaticals in Berlin in 1927 and 1934. There he became an acquaintance of Einstein. Years later he mentioned talking science to the fellow one afternoon, and I quote: "about a publication of the previous year - on the 'Fünf-bein' as I recall. 'Das ist alles Mist.'" Google fails me on what what the Fünf-bein might refer to, much less why it is all crap. Any thoughts appreciated.
posted by BWA at 11:12 AM - 7 answers

December 26, 2016

Mitigating static electricity

I live in the mountain west. It's pretty dry here all the time... quadruply so in the winter. I work from home, and constantly shock myself whenever I sit down at my desk. Pretty much year round walking across the carpet and sitting down at my desk will shock me. During the winter merely shifting in my chair will shock me. What the heck can I do to mitigate this? [more inside]
posted by so fucking future at 3:07 PM - 13 answers

Looking for a forester (not a car)

I need to find a forester in Southern Maine and I don't know where to begin. I have looked at the list on the Society of American Foresters but it seems like there is no division as to who is a employed by a company versus who is available for hire. [more inside]
posted by InkaLomax at 11:44 AM - 8 answers

Can you see Brittany from a cliff in Cornwall?

I'm reading a novel set near Polruan in which the author claims that you can see France with the naked eye from the top of a cliff on a clear day. I've tried a number of searches, including a horizon calculator, and it doesn't look feasible. Is this just a case of poetic license on the author's part?
posted by mareli at 5:39 AM - 13 answers

testing tap water - home chemistry

I'm looking for resources and advice how to do precise enough quantitative chemistry for determining why chicken broth cooked in my hometown and in my wife's hometown tastes different. I can get some basic glass and labware, but no fancy reagents or advanced tools (obviously). Is it possible to do this using simple but precise measurements and common reagents? Culinary detective story inside. [more inside]
posted by kmt at 5:18 AM - 7 answers

December 10, 2016

Can you help me identify this ant? It's invading my house!

These ants are invading my bathroom. Does anyone know what kind of ants they are? pic
posted by Kerborus at 11:42 PM - 8 answers

December 9, 2016

Where is he (it) my beloved Siberian Crane?

I am a fan of the Siberian Crane who took a wrong turn and ended up in Taiwan. Now in Japan, maybe? Problem: I can't read Chinese. [more inside]
posted by sacchan at 6:10 AM - 4 answers

December 6, 2016

Physics Filter: Height of capillary rise

Where can I buy a glass capillary tube so narrow such that I can see the maximum capillary rise for water? [more inside]
posted by SunPower at 6:22 PM - 3 answers

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