Recent comments in /f/askscience

Indemnity4 t1_j98hp0j wrote

Reply to comment by That_Comic_Who_Quit in How are airport luggage tags sticky without being sticky? by That_Comic_Who_Quit

Pressure sensitive adhesive.

The glue material is "tacky" - that's a science word in this context.

Imagine an elastic band, maybe holding up your underwear. You can pull it to deform the shape, but it wants to snap back to the original shape.

The glues have lots of little hairs, sub-microscopic in size. When you push/pull them, the hairs move just a little and get fluid enough to move and flow into tiny little microscopic crevices on material. When you stop applying pressure, the hairs stiffen up and get hard - just like holding onto a cliff with your fingertips.

The amount of pressure required to make the glue into a fluid is one property that gets measured. How strong it is attached to a surface before it detaches is another.

tl;dr it's very much similar to Velcro hook-and-loop material

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Indemnity4 t1_j98g59p wrote

Reply to comment by LucyEleanor in Will a sheet of paper go brown with age over the decades if kept in a dark waterproof container? by west_ozzie

It still depends on the paper source.

Particularly as recycling is more popular, there are many types of paperstock available to suit all customer cost/needs.

Regular officepaper contains optical brightening agents to make it look very white and clean. That will not last more than 25 years due to residual acid stating to dissolve the paper. Pressure has little effect on that.

If you ever have to publish a thesis or a museum/archival print, they will specify certain grades of paper. In some cases, they won't even allow other grades into the same box to prevent them damaging the archival pieces.

Acid-free paper itself comes in two types: permanent and archival.

There is a whole history of cheap paperback novels that are lost to time because they were printed on cheap paper. Same issue affects museum pieces and historical libraries.

1867 is the magic year in history when paper became worse - it is when the first factory to build wood pulp paper was built and within a decade, 95% of all paper was wood pulp - it was just so cheap and plentiful. When you hear of super old documents being found in a desert or some old library cupboard, more often than not it was printed on animal hides or rag-fibre. Modern wood pulp paper has fundamental chemical differences that mean it is always slowly decaying. Additives are required to slow the decay, but eventually like fuel in a a car, the additives are exhausted.

In your lifetime the only printed material you have likely seen that isn't wood pulp paper is the US currency. That is still printed on rag paper.

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Indemnity4 t1_j98ec6u wrote

Reply to comment by darthaxolotl in Can doctors tell when cancer is caused by something specific, such as smoking or chemicals? by [deleted]

Statistics are great fun!

About 20% of the lung cancer deaths in the USA are non-smokers, or ~7000 people a year.

While lots of people know about smoking=cancer, most don't know about smoking=COPD or heart disease. Cancer sure is up there as the scariest, but it's not the thing that will probably kill you.

Crudely, very roughly taking those numbers: smokers are ONLY 4X more likely to die from lung cancer than general population. That's, surprisingly not that much higher. There are way riskier activities such as SCUBA diving or living near a busy road.

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Glasnerven t1_j98c8t4 wrote

Reply to comment by PogTuber in When something is bent (a metal ruler for example) and returns to its original shape, what is happening on the molecular level? Where is the information of the original shape stored and what forces do the unbending? by JewNugget2525

To borrow a phrase from XKCD: "You wouldn't die of anything; you'd just stop being biology and start being physics."

Obviously we experience the results of nuclear events any time we're out in the sunlight. However, we receive those results via electromagnetism--and gravity, because the sun affects the tides. Nuclear forces govern the fission reactions at the heart of nuclear power, but the heat is transferred via EM forces. Even in the event of a nuclear weapon explosion, the gamma ray pulse is EM, the thermal pulse is EM, the visible light is EM, and when the blast wave hits, it's doing damage by EM forces, too.

Maybe it's just my lack of imagination, but I don't see how a person could directly experience the strong or weak nuclear forces without being part of a significant fission, fusion, or decay event.

However: it turns out that only about 1% of the mass of a proton is composed of the rest mass of the quarks that make it up. The other 99% is the binding energy holding everything together, which is an effect of the strong nuclear force.

So, get a liter bottle of water and wave it around. Feel the heft. You're pushing on that bottle via electromagnetic forces, but 990 grams of that mass you're playing with is nuclear force.

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Unlikely_Plankton_11 t1_j989zk0 wrote

Reply to comment by darthaxolotl in Can doctors tell when cancer is caused by something specific, such as smoking or chemicals? by [deleted]

It's a lot for sure. Huge number. It's just kind of less than you would have thought. And keep in mind that the category of "smokers" has both those who smoke a pack a week and those who smoke 5 packs per day.

Even if you smoke a pack a day for 20 years, your risk of getting lung cancer - while way higher than someone who has never smoked, is still surprisingly low in an absolute sense. I would have thought it'd be like 80% or something. Not the case. It turns out that as far as smokers go, a pack a day is "light."

All of the other health effects, however, are honestly a much more compelling reason to quit. It's easy to brush off an elevated but still unlikely death by cancer. But it's not like you're fine and then you just up and die one day when you're 85. That honestly wouldn't be so bad at all. Much more common is that you'll live much of your life with weird chest pains, coughing every morning, getting out of breath going on walks, etc. Planning your life around smoke breaks and not smelling like smoke before going to the office or on a date, keeping your car/house from smelling like smoke, etc. Your QOL goes way down long before you get cancer - if you ever even do.

That was what motivated me to quit smoking when I was 26. And uh...again when I was 32 (though I quit for 2 years in the middle). I could feel that I was a smoker, and that was scary. You're not supposed to feel sick when you take a deep breath.

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