Why Does It Feel So Cold When You Step Out of the Shower?

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iStock

Waking up is hard, but for some of us, getting out of the shower in the morning is harder. Things are dandy at first: You step into the basin and happily roast under a steamy blanket of hot water. But then you shut off the shower faucet, open the curtain, and whoosh! You’re a human popsicle. Why does stepping out from a warm shower make your bathroom feel like Antarctica?

The answer is evaporation. When you step off the bathmat, the water clinging to your skin starts to evaporate. But to change into a gas, that water needs help—namely, it needs heat energy. It acquires that energy by sapping heat from your surroundings. In the case of your morning shower, the evaporating water sucks up heat energy from the droplets that stay clinging to your body. The result? The water on your body cools—and so do you. (The water glistening on your skin isn’t the only thing that gets icy. Evaporation also absorbs heat from your skin, making you shiver even more!)

Evaporative cooling may be annoying when you take a wintertime shower, but it’s handy during the stifling summer days. It’s what makes sweat—your body’s cooling mechanism—work. Of course, sweat doesn't always cool you down; it can be useless on a muggy afternoon. The air is so saturated with water that your sweat can’t evaporate, leaving you hot and soggy.

Which explains why stepping out of the shower can be such a jolt. The cocoon behind the curtain traps a lot of water vapor, keeping the air in the shower moist and warm. But the air outside the curtain isn’t as humid. So when you step out of the shower, you enter an environment primed to make the water on your skin evaporate quickly. Add in the fact that warm water evaporates faster, and your bathroom can feel like an icebox.

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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