Why Do Paper Cuts Hurt So Much?

Vonschonertagen/iStock via Getty Images
Vonschonertagen/iStock via Getty Images

There are a couple things at play here, some involving the paper, some involving your skin.

For one thing, what part of your body comes in contact with paper the most? Right, the majority of paper cuts happen on the fingers and hands. Your hands are pretty complex sensory instruments, and they’re absolutely jam-packed with nerve fibers called nociceptors. These guys sense temperature, pressure and pain, and there are more of them per square inch in your hands and fingers than most other parts of your body. Injuries there are noticed much more than similar injuries elsewhere. The same small paper cut on a less nerve-dense area, such as, say, your leg, won’t send nearly as many pain signals to your brain.

To make matters worse, it’s not like you can just not use your hands for a few days after every paper cut. You’ve got stuff to touch and things to pick up, so while the cut heals, the skin keeps moving and the edges of the wound tend to get pulled apart, delaying healing and prolonging the pain.

All right, sure, your hands are very sensitive, but then why do paper cuts hurt more than some cuts made by other objects, like knives? Well, the blade of even a fairly dull knife tends to be more straight and sharp than the dull and flexible edge of a piece of paper. When a knife cuts your skin, it leaves a relatively clean cut compared to paper, which will flex a little and do more microscopic damage to the skin. Paper also makes a more shallow wound than most other cutting injuries. A shallow cut on the surface might only bleed a little, or not at all. Without a blood clot to protect them, the nerves around the cut are exposed to air and other irritants, which can make the pain more noticeable and longer lasting.

Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

This post originally appeared on Quora. Click here to view.

What Makes a Hotel Breakfast 'Continental'?

Hotels often offer a complimentary pastry and fruit breakfast.
Hotels often offer a complimentary pastry and fruit breakfast.
tashka2000/iStock via Getty Images

The continental breakfast, which is typically made up of pastries, fruit, and coffee, is often advertised by hotels as a free perk for guests. But why is it called continental, and why don’t patrons get some eggs and bacon along with it?

The term dates back to 19th century Britain, where residents referred to mainland Europe as “the continent.” Breakfast in this region was usually something light, whereas an English or American breakfast incorporated meat, beans, and other “heavy” menu options.

American hotels that wanted to appeal to European travelers began advertising “continental breakfasts” as a kind of flashing neon sign to indicate guests wouldn’t be limited to American breakfast fare that they found unappealing. The strategy was ideal for hotels, which saved money by offering some muffins, fruit, and coffee and calling it a day.

That affordability as well as convenience—pastries and fruit are shelf-stable, requiring no heat or refrigeration to maintain food safety—is a big reason continental breakfasts have endured. It’s also a carryover from the hybrid model of hotel pricing, where American hotels typically folded the cost of meals into one bill and European hotels billed for food separately. By offering a continental breakfast, guests got the best of both worlds. And while Americans were initially aghast at the lack of sausages and pancakes on offer, they’ve since come around to the appeal of a muffin and some orange juice to get their travel day started.

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