Recent comments in /f/askscience

The_RealKeyserSoze t1_j94iqkm wrote

Reply to Why are fevers cyclical? by Key-Marionberry-9854

There are a lot of signals controlling inflammation and fever. But one of the simplest explanations is cortisol. Fevers tend to spike at night when cortisol levels are low but subside in the morning when cortisol levels are highest.

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sf_d t1_j94fib6 wrote

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

Airport luggage tags use pressure-sensitive adhesives, which stick to the luggage when pressure is applied but do not require any moisture or heat to become sticky.

The adhesive used on luggage tags is a type of acrylic adhesive that is applied to the back of the tag in a thin layer. When the tag is applied to the luggage, pressure is applied to the adhesive layer, causing it to flow into the surface of the luggage and create a bond.

These adhesives are designed to be strong enough to keep the tag in place during transit but can also be easily removed by the baggage handlers or the owner of the luggage. This is why you can easily peel off the luggage tag without leaving any residue on your luggage.

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[deleted] t1_j94dnn2 wrote

Reply to comment by monsieurkaizer in Was reading something related to Rock Salt mining. In places like the Himalayas where rock salt mining is done in cold temperatures, a lot of miners report burns. Why is it so that salt burns in a colder surroundings? Would it be the same reason why the salt ice challenge was so dangerous? by vvdmoneymuttornot

Molten is only really used with things that are hot and will solidify again at room temp.

For example there is molten chocolate and there is liquid chocolate(sauce). They have clear definitions and are straight up never used interchangeably. Its like a rectangle and square.

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TheKidInMe t1_j94cdwe wrote

Reply to Why are fevers cyclical? by Key-Marionberry-9854

Homeostasis! This is a pillar of human biology.

There are several systems working entirely independent from each other.

The system responsible for keeping you at normal temperatures will act independently. Weather you are sick, exercising, or spending the day at the beach— if you are hot, it wants to turn it down. It’s toolbox includes things like sweating or sending out chemicals. The hotter you get, the more this system will ramp up to turn it off.

The immune system will also act independently. Thankfully, the immune system is very smart and can learn when to use its tools, including inducing a fever. The tools of the immune system and how it’s used is an entire field of study.

Whether it’s the course of an illness or walking in and out of shade on a hot day, your body systems will compete with stronger and weaker signals depending on how important system feels it needs to use their toolbox.

Understanding how each system works and being able to identify when things go out of whack is pretty much the field of medicine.

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Allfunandgaymes t1_j94a6oz wrote

Reply to How do spider eyes work? by NoMoreMonkeyBrain

It isn't the same for all spiders. Some - like the jumping spiders - have extremely acute vision with front-facing primary eyes for images and auxillary side eyes to detect motion. Other spiders - such as tarantulas and many web weavers - are nearly blind, as they detect prey mainly through vibrations and do not require refined vision.

Mechanically, spider eyes are not like compound eyes of insects that transmit hundreds to thousands of micro-images to an immobile inner eye. They are made of single immobile lenses, with mobile retinas behind them that can shift focus to separate lens ports. This is readily apparent in certain species of spider with partially translucent exoskeletons and eye lenses, such as the magnolia green jumping spider. The two front eye lenses remain immobile, but you can see a small black retina shifting behind them. Because their lenses are immobile, the spider's field of view is very narrow, so they must turn their bodies to look around. Not all spiders are capable of such focused sight - the aforementioned tarantulas basically have a teeny tiny eyeport on the top of their bodies with rudimentary eye spots that can only detect light and some motion, but can't produce a focused image.

Generally, spiders that evolved to actively hunt down prey evolved the more sophisticated, forward-facing primary eyes, and those that adopted a more passive method of obtaining prey - like spinning a web and waiting for something to get caught - did not. The diversity of body morphology among spiders is truly mind-blowing.

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DeftTurnOfPhrase t1_j94a0xa wrote

Reply to comment by [deleted] in Was reading something related to Rock Salt mining. In places like the Himalayas where rock salt mining is done in cold temperatures, a lot of miners report burns. Why is it so that salt burns in a colder surroundings? Would it be the same reason why the salt ice challenge was so dangerous? by vvdmoneymuttornot

This basically does happen in places with high humidity. It doesn't become "full" of water, but the salt clumps together enough to become impossible to shake out of the container. One remedy is to mix the salt with dry rice, which is either more of a desiccant than salt or has a mechanical effect that breaks up the clumps.

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Kolemawny t1_j949toz wrote

Reply to comment by [deleted] in Was reading something related to Rock Salt mining. In places like the Himalayas where rock salt mining is done in cold temperatures, a lot of miners report burns. Why is it so that salt burns in a colder surroundings? Would it be the same reason why the salt ice challenge was so dangerous? by vvdmoneymuttornot

There is a humidity difference between your kitchen and an underground mine.

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