How Much Does a Cloud Weigh?

iStock / B&M Noskowski
iStock / B&M Noskowski

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. 

10 Things You Should Know About Asthma

iStock.com/Wojciech Kozielczyk
iStock.com/Wojciech Kozielczyk

To anyone with asthma, the feeling of an attack is unmistakable. Patients have compared an asthma attack's feeling of breathlessness, caused by inflammation in the lungs and airways, to being smothered by a pillow or having an elephant sit on their chest. Medical experts have already figured out some aspects of asthma, like how to diagnose and treat it, but other components, like what causes asthma and how to cure it, remain unclear. From the triggers people encounter at work to the connection to allergies, here are some facts about asthma symptoms and treatments you should know.

1. Asthma attacks are related to allergies.

The physical process that occurs when someone has a sneezing fit during pollen season is similar to what happens during an asthma attack. But while the former causes discomfort, the latter produces potentially life-threatening symptoms. When people with allergies are exposed to an allergen like pollen, they produce antibodies that bind to that allergen. This signals the body to release the chemicals that cause allergic symptoms. In most people, the symptoms are limited to the head, such as a runny nose or watery eyes, but in people with asthma, they're felt in the lungs. If the lungs are inflamed, the airways that carry air swell up and fill with mucus, constricting airflow and causing common asthma symptoms like coughing, wheezing, and shortness of breath. Such asthma attacks can be fatal when patients can’t get enough air to their lungs.

2. Asthma is the most prevalent chronic disease among children.

Asthma is common, affecting 25 million in the U.S. alone, and of those patients, about 7 million are children. Most people with the disease develop it during childhood. Asthma is the most prevalent chronic illness among kids, and each year, students miss 13.8 million school days because of it.

3. Asthma may be inherited.

Doctors aren’t entirely sure what causes asthma, but they know it sometimes runs in families. A 2010 study found that people with one parent with the condition were nearly twice as likely to have it themselves, and people with a parent and a grandparent with asthma were four times more likely to develop it. Because asthma is connected to allergies, a genetic disposition toward allergies, known as atopy, may explain some inherited asthma cases.

4. Asthma is surprisingly easy to diagnose.

One of the simplest ways to diagnose asthma is through a lung function test. If a patient is reporting asthma symptoms (coughing, chest tightness, a feeling of not getting enough air), their doctor may check the strength of their exhalations before and after having them use an inhaler. If their breathing improves with the medicine, they likely have asthma. An X-ray of the patient’s chest can also be used to reach an asthma diagnosis.

5. Kids who grow up around germs are less likely to have asthma.

A person’s environment early in life may also play a role in whether or not they develop asthma. People who grew up in rural areas, around animals, and in large families are less likely to have asthma than those who did not. One possible explanation is the hygiene hypothesis: According to this theory, kids who were exposed to germs and pathogens while their immune systems were developing are better equipped to deal with allergens, while kids who were sheltered from germs may be more likely to have an exaggerated (and in the case of asthma, potentially deadly) immune response to harmless substances. The hygiene hypothesis hasn’t been proven, however, and it’s definitely not an excuse to expose children to infections in an attempt to strengthen them against asthma attacks in the future.

6. Asthma triggers are everywhere.

To manage their symptoms, doctors tell asthma patients to limit exposure to their triggers when possible. Common asthma triggers include irritants and allergens like dust, tobacco smoke, car exhaust, mold, pet dander, and smoke from burning wood. Triggers that don’t come from the environment, like colds, sinus infections, acid reflux, and hyperventilation brought on by stress, can be even harder to avoid.

7. There's one asthma trigger patients shouldn't avoid.

Physical activity causes fast breathing, which can provoke asthma attacks in some people with the condition. There’s even a type of asthma called exercise-induced bronchoconstriction that specifically describes people who suffer from these kinds of attacks. But the risks of living a sedentary lifestyle outweigh those of exercising carefully, even with asthma. Instead of cutting out cardio altogether, doctors work with patients to come up with an exercise plan that’s safe for them. This might include warming up and using an inhaler before working out, practicing cool-down activities afterward, and wearing scarves or masks to limit exposure to irritants that may also trigger asthma symptoms.

8. There are two types of asthma treatments.

Long-term controllers and quick-relievers are the two types of medications used to treat asthma. Immediate medicines like short-acting beta agonists and anticholinergics relax muscles in the airways when flare-ups occur, and they’re typically administered directly to the lungs with an inhaler. Long-term medications help keep asthma symptoms under control over time are taken as often as once a day, regardless of whether symptoms are present. They include inhaled long-acting beta agonists and corticosteroids, biologic injections, and theophylline and leukotriene modifier pills and liquids. All of these medications suppress asthma symptoms by either relaxing muscles, reducing swelling, or preventing inflammation in the airways.

9. Asthma can be an occupational hazard.

Occupational asthma develops when a patient’s triggers come from their work environment. According to the National Institutes of Health, wood dust, grain dust, animal dander, fungi, and various chemicals are some of the most common asthma triggers that patients encounter in the workplace. Bakers, farmers, laboratory workers, millers, and woodworkers predisposed to asthma are all at higher risk.

10. There's no cure for asthma, but symptoms can lessen over time.

Though asthma is treatable, there’s no cure for the chronic illness. Some people, however, do appear to grow out of the condition after suffering from it as kids. It’s possible for asthma symptoms to become less severe and go into remission as patients get older, but once someone is diagnosed with asthma, the risk of an episode never goes away completely. Changes in hormone levels are a factor that could possibly bring asthma symptoms back in patients who haven’t experienced an attack in years.

James Cameron Directed Entourage's Aquaman, But He Could Never Direct the Real One

Tommaso Boddi, Getty Images for AMC
Tommaso Boddi, Getty Images for AMC

Oscar-winning director James Cameron is no stranger to CGI. With movies like Avatar under his belt, you’d expect Cameron to find a particular sort of enjoyment in special effects-heavy movies like James Wan's Aquaman. But Cameron—who directed the fictional version of Aquaman featuring fictional movie star Vinnie Chase in the very real HBO series Entourage—has a little trouble with suspension of disbelief.

In a recent interview with Yahoo!, Cameron said that while he did enjoy Aquaman, he would never have been able to direct the movie itself because of its lack of realism.

"I think it’s great fun,” Cameron said. “I never could have made that film, because it requires this kind of total dreamlike disconnection from any sense of physics or reality. People just kind of zoom around underwater, because they propel themselves mentally, I guess, I don’t know. But it’s cool! You buy it on its own terms.”

"I’ve spent thousands of hours underwater," the Titanic director went on to say. "While I can enjoy that film, I don’t resonate with it because it doesn’t look real.”

While Aquaman was shot on a soundstage, Cameron will be employing state-of-the-art technology that will allow him to actually be underwater while shooting underwater scenes for his upcoming Avatar sequels.

[h/t Yahoo!]

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