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How Much Does a Cloud Weigh?

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Reader Jane wrote in to note that clouds look so nice and fluffy and lighter-than-air, so they certainly can’t weigh much. Right? 

When Peggy LeMone was in junior high, a friend’s dad pondered that same question, and she kept it in the back of her mind for years. Now all grown up, LeMone is a researcher at the National Center for Atmospheric Research, and she’s figured out an answer. Today, she shares her cloud-weighing technique with us. 

First, figure out how dense the cloud is. Scientists have measured the water density of a typical cumulus cloud (the white, fluffy ones you see on a nice day) as 1/2 gram per cubic meter—about a small marble’s worth of water in a space you and a friend could comfortably sit in. The density will be greater for different types of clouds. 

Next, figure out how big the cloud is. By measuring a cloud’s shadow when the sun is directly above it, you can get an idea of its width. LeMone does this by watching her odometer as she drives under a cloud. A typical cumulus, she says, is about a kilometer across, and usually roughly cubical—so a kilometer long and a kilometer tall, too. This gives you a cloud that’s one billion cubic meters in volume. 

Do the math with the density and volume to determine the total water content of the cloud. In this case, it's 500,000,000 grams of water, or 1.1 million pounds. That’s a lot of weight to wrap your head around, so LeMone suggests putting it in more familiar terms, like elephants. That cloud weighs about as much as 100 elephants. If you’re a Democrat and you’re feeling partisan, she says, you could substitute 2500 donkeys. If you care more for dinosaurs than politics, you could also say the cloud weighs about as much as 33 apatosauruses.

If all those elephants or donkeys or dinosaurs were hanging out in the sky, they’d fall. So how does a several-hundred-ton cloud stay afloat? For one thing, the weight isn’t concentrated in a hundred elephant-sized particles or even a billion marble-sized ones. It’s distributed among trillions of really tiny water droplets spread out over a really big space. Some of these droplets are so small that you would need a million of them to make one raindrop, and gravity’s effect on them is pretty negligible. 

What’s more, the cloud is less dense than dry air, so it's buoyant. It also helps that all those little droplets get some lift from updrafts of warm air. Those droplets don’t float forever, though. When the cloud’s water density increases and the droplets get bigger and heavier, the cloud eventually does fall, bit by little bit, in the form of rain. 

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Big Questions
What Do Morticians Do With the Blood They Take Out of Dead Bodies?
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Zoe-Anne Barcellos:

The blood goes down the sink drain, into the sewer system.

I am not a mortician, but I work for a medical examiner/coroner. During an autopsy, most blood is drained from the decedent. This is not on purpose, but a result of gravity. Later a mortician may or may not embalm, depending on the wishes of the family.

Autopsies are done on a table that has a drain at one end; this drain is placed over a sink—a regular sink, with a garbage disposal in it. The blood and bodily fluids just drain down the table, into the sink, and down the drain. This goes into the sewer, like every other sink and toilet, and (usually) goes to a water treatment plant.

You may be thinking that this is biohazardous waste and needs to be treated differently. [If] we can’t put oil, or chemicals (like formalin) down the drains due to regulations, why is blood not treated similarly? I would assume because it is effectively handled by the water treatment plants. If it wasn’t, I am sure the regulations would be changed.

Now any items that are soiled with blood—those cannot be thrown away in the regular trash. Most clothing worn by the decedent is either retained for evidence or released with the decedent to the funeral home—even if they were bloody.

But any gauze, medical tubing, papers, etc. that have blood or bodily fluids on them must be thrown away into a biohazardous trash. These are lined with bright red trash liners, and these are placed in a specially marked box and taped closed. These boxes are stacked up in the garage until they are picked up by a specialty garbage company. I am not sure, but I am pretty sure they are incinerated.

Additionally anything sharp or pointy—like needles, scalpels, etc.—must go into a rigid “sharps” container. When they are 2/3 full we just toss these into one of the biotrash containers.

The biotrash is treated differently, as, if it went to a landfill, then the blood (and therefore the bloodborne pathogens like Hepatitis and HIV) could be exposed to people or animals. Rain could wash it into untreated water systems.

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

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Big Questions
Why Does Asparagus Make Your Pee Smell Funny?
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The asparagus has a long and storied history. It was mentioned in the myths and the scholarly writings of ancient Greece, and its cultivation was the subject of a detailed lesson in Cato the Elder's treatise, On Agriculture. But it wasn't until the turn of the 18th century that discussion of the link between asparagus and odorous urine emerged. In 1731, John Arbuthnot, physician to Queen Anne, noted in a book about food that asparagus "affects the urine with a foetid smell ... and therefore have been suspected by some physicians as not friendly to the kidneys." Benjamin Franklin also noticed that eating asparagus "shall give our urine a disagreeable odor."

Since then, there has been debate over what is responsible for the stinky pee phenomenon. Polish chemist and doctor Marceli Nencki identified a compound called methanethiol as the cause in 1891, after a study that involved four men eating about three and a half pounds of asparagus apiece. In 1975, Robert H. White, a chemist at the University of California at San Diego, used gas chromatography to pin down several compounds known as S-methyl thioesters as the culprits. Other researchers have blamed various "sulfur-containing compounds" and, simply, "metabolites."

More recently, a study demonstrated that asparagusic acid taken orally by subjects known to produce stinky asparagus pee produced odorous urine, which contained the same volatile compounds found in their asparagus-induced odorous urine. Other subjects, who normally didn't experience asparagus-induced odorous urine, likewise were spared stinky pee after taking asparagusic acid.

The researchers concluded that asparagusic acid and its derivatives are the precursors of urinary odor (compared, in different scientific papers, to the smell of "rotten cabbage," "boiling cabbage" and "vegetable soup"). The various compounds that contribute to the distinct smell—and were sometimes blamed as the sole cause in the past—are metabolized from asparagusic acid.

Exactly how these compounds are produced as we digest asparagus remains unclear, so let's turn to an equally compelling, but more answerable question:

WHY DOESN'T ASPARAGUS MAKE YOUR PEE SMELL FUNNY?

Remember when I said that some people don't produce stinky asparagus pee? Several studies have shown that only some of us experience stinky pee (ranging from 20 to 40 percent of the subjects taking part in the study, depending on which paper you read), while the majority have never had the pleasure.

For a while, the world was divided into those whose pee stank after eating asparagus and those whose didn't. Then in 1980, a study complicated matters: Subjects whose pee stank sniffed the urine of subjects whose pee didn't. Guess what? The pee stank. It turns out we're not only divided by the ability to produce odorous asparagus pee, but the ability to smell it.

An anosmia—an inability to perceive a smell—keeps certain people from smelling the compounds that make up even the most offensive asparagus pee, and like the stinky pee non-producers, they're in the majority.

Producing and perceiving asparagus pee don't go hand-in-hand, either. The 1980 study found that some people who don't produce stinky pee could detect the rotten cabbage smell in another person's urine. On the flip side, some stink producers aren't able to pick up the scent in their own urine or the urine of others.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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