Squirrels can survive a fall from any height, at least hypothetically (McGill OSS)

1 minute read

Squirrels, in theory, can survive a fall from an object of any height due to two factors: their size and their mass. A force (such as the force of gravity) is calculated by multiplying mass and acceleration. The acceleration due to gravity on Earth is always roughly 9.81 m/s², regardless of what object it is acting on. Squirrels are not very heavy—a grey squirrel only weighs about 0.5 kg—meaning that the force acting on a falling squirrel just isn’t that big.

Force = mass*acceleration = 0.5 kg * 9.81 m/s² = 4.9 N

We measure forces in a unit called “Newtons”, named for Isaac Newton who gave us Newton’s three laws of motion.

Compare this to, for example, a falling 60 kg human, which would be pulled downward with a force of about 489 N. A factor of 100 higher!

On top of being small, squirrels are fluffy and intuitively spread their bodies out when falling. This allows them to experience as much wind resistance as possible, slowing down their rate of descent. Some squirrels even use this fact to glide through the air. While gliding is not the same as flight, we nonetheless call them flying squirrels.

For these two reasons, the terminal velocity (fastest speed while falling) of squirrels is slow enough that they will, at least in principle, never fall so hard that they hurt themselves.

This article was originally posted here: https://www.mcgill.ca/oss/article/did-you-know/squirrels-can-survive-fall-any-height-least-hypothetically

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Birds Seem To Be Scared of Googly Eyes, and That’s a Good Thing (McGill OSS)

3 minute read

Every year upwards of 25 million birds are killed in Canada due to collisions with buildings, communication towers, wind turbines, and as a result of being tangled into marine gillnets. From window decals to flashing lights, humans have tried numerous preventative measures to stop these deaths. Their degree of success depends on the method, the location, and the types of birds in that ecosystem—amongst many other factors—and results are highly variable.

What may seem like benign interventions that—at worst—just won’t work, actually have the capacity to do harm. As an example, In Peru, bycatch (i.e., accidental catch) of Guanay Cormorants was reduced more than 80% after researchers attached green lights to gillnets. At the same time, bycatch of Peruvian Boobies increased. Possibly due to the boobie’s attraction to the lights.

Similarly, when researchers set out to the Baltic sea to compare the effects of attaching light panels, constant green lights, or flashing white lights to gillnets on sea birds (in particular the Long-tailed duck, a vulnerable species) they found that the nets with flashing white lights caught more ducks than the normal, non-illuminated ones.

One approach that is so far quite promising involves using giant looming googly eyes.

To continue reading for free, click here- https://www.mcgill.ca/oss/article/did-you-know-general-science/birds-seem-be-scared-googly-eyes-and-thats-good-thing

Why Is Diet Coke So Fizzy? (McGill OSS)

1 minute read

Whether you’re buying ingredients for an at home “Coke and Mentos” demonstration, asking a flight attendant for a beverage, or just trying to pour a can of soda into a glass before hockey comes back on, you may have noticed something: Diet sugar-free sodas fizz more than regular sugar-rich sodas when opened.

The degree of carbonation or “fizziness” of a soda is partly a function of how easily carbon dioxide bubbles can form in the sugary flavour water we call pop. When it’s easier for bubbles to form, you get more of them and therefore an increased “fizziness”.

When a liquid has a high surface tension, it means that the bonds between the liquid’s molecules are very strong. Surface tension is why some spiders can walk on water—the spider’s weight isn’t enough to break apart the water molecules! In a substance with high surface tension, bubbles will not form very easily.

Surfactants are chemicals that decrease the surface tension of a liquid. They will therefore make it a bit easier for bubbles to form. Regarding Diet Coke, aspartame, and potassium benzoate (a preservative) are surfactants! Caffeine as well, but it has much less of an effect due to its low concentration.

Bubbles of gas will struggle to form in very viscous liquids, like maple syrup or waffle batter. Diet soda actually has a slightly higher viscosity than sugary soda, which slightly diminishes its fizzing potential. However, a slightly higher viscosity means that when bubbles do form, they’re a bit more stable. This explains why Diet Coke not only fizzes more than classic Coke, but the foam also lasts longer!

Originally posted here- https://www.mcgill.ca/oss/article/did-you-know/why-diet-coke-so-fizzy

Why is poop brown? (McGill OSS)

1 minute read

A certain amount of the muddy colour can be attributed to the different colours of food we eat. Like mixing all the paint colours together, the result is a dull brown. But, much bigger factors for humans’ brown poop are bilirubin and bile. Bilirubin is a yellow substance found in the liver, the product of the breakdown of old red blood cells. Bile is dark brown or green and is produced by the liver to help digest fats. Both of these substances are secreted into the small intestine during digestion, and slowly make their way into poop, bringing with them a dark brown hue.

Bird poop, on the other hand, is not brown but white. That is because—unlike mammals—birds don’t pee!

To read the entire article, click here: https://www.mcgill.ca/oss/article/health-and-nutrition-did-you-know/why-poop-brown

Do We Actually Need To Eat More Calories When Menstruating? (Skeptical Inquirer)

4 minute read

Shark week, moon time, the crimson tide, a visit from Auntie Flo: whatever you call it menstruation is the roughly monthly interval during which the uterus sheds its lining. For the uterus owner, it is not generally a super fun time; cramping, bloating, headaches, and fatigue are just a few of the symptoms associated with “that time of the month.”

The symptom I want to focus on today, though, is hunger. Whether for chocolate, pizza, or any food really, an increased hunger is a commonly reported phenomenon during, or right before, menstruation. Although we know that periodic (get it?) changes in appetite can be influenced by fluctuations in hormones such as estrogen and progesterone, I became curious whether this increase in hunger also correlated with an actual increased need for energy from food. Just like our bodies produce the sensation of thirst when they require more hydration, maybe they produce the sensation of hunger during menstruation in part because of an increased caloric need.

Read the entire article here: https://skepticalinquirer.org/exclusive/do-we-actually-need-to-eat-more-calories-when-menstruating/

The Science of Cold Brew (McGill OSS)

2 minute read

A few weeks ago I finally had enough of the cold brew trend and decided to see what all the hype was about. I followed this recipe (because $5 at Starbucks is just too much for me), and was surprised to find cold brew wonderfully smooth, sweet and mild. I love coffee, and though I drink it with milk and sugar, I’ve never especially been bothered by the bitterness or acidity of traditionally brewed coffee. None the less, cold brew is quite amazing, and it left me wondering what the chemistry behind it was. 

It turns out that hot water (about 93 ℃ in most drip coffee makers ) accelerates the extraction of molecules and chemicals that, once mixed with water, form the coffee we know and love. Once brewed, the coffee continues to react with air and water molecules. This is why coffee goes stale. Heat accelerates these reactions (as it does most), so coffee left on a burner, or in your car, all day goes staler more rapidly. 

In cold brew, however, there is no heat to help extract these molecules and to cause the break down of others. The time the cold brew is left brewing allows the chemicals to be extracted from the coffee grounds much like the heat does, but you do get different amounts of different chemicals, leading to a different taste. Notably, many molecules that taste bitter are not extracted in large amounts in the absence of heat, which explains cold brew’s sweetness. You may have also seen cold brew being sold pre-packaged in stores, a possibility that is afforded to it due to the cold water not accelerating the ‘staling’ process.

So for once it seems like the hype was justified, though I’ll stick to making my cold brew at home. 

Originally posted here: https://www.mcgill.ca/oss/article/did-you-know-general-science/cold-brew-coffee

An Asthma Attack Caused by a Thunderstorm (McGill OSS)

Photo by Matteo Zamaria

1 minute read

On November 21st, 2016 a thunderstorm swept across Melbourne, Australia. It brought with it the usual flooded basements, wet shoes and ruined picnics, but it also brought a strange outbreak of asthma. Asthmatics and non-asthmatics alike suddenly found themselves unable to catch their breath, coughing and in extreme cases not being able to breathe at all. By the time the storm had passed, there was a 672% increase in respiratory-related presentations to emergency departments and a 992% increase in asthma-related admissions to hospital. The storm contributed to the death of at least 10 people.

So what was it about this thunderstorm that spurred a city-wide asthma attack? Experts aren’t certain, but the best guess is pollen. It seems that polled, mould and other allergens can get picked up into a storm, riding on wind currents, and carried into the clouds. Up in the sky, they make contact with water molecules, which causes these allergens to break apart into microscopic particles that can more readily enter human lungs and cause reactions. 
In the case of Melbourne, the allergen of importance seems to be from ryegrass. A grain of ryegrass pollen can be broken down into 700 starch granules, measuring 0.6 to 2.5 μm, which may then be inhaled into the deepest parts of the lungs, and cause an asthma attack or an allergic reaction.

As roughly 20% of the world is sensitive to grass or tree pollens, you can imagine that these storms are quite bothersome to many. Melbourne wasn’t the first case of casualties due to storm inflicted asthma, and it sadly will probably not be the last. 

Article originally posted here: https://www.mcgill.ca/oss/article/did-you-know-health/thunderstorms-cause-asthma-attacks

Can Periods Really Sync Up? (McGill OSS)

1 minute read

The idea that periods can synchronize was first investigated in a 1970’s paper by Martha McClintock, who examined the menstrual cycles of women living together in dorms. McClintock found that after 7 months of living together, the women’s periods had gone from an average of 6.5 days apart to 4.6 days apart, leading to the idea that proximity caused the periods of these women to synchronize due to some chemical signal.

However, studies since then have been largely unable to replicate these findings. McClintock’s results are now largely believed to have occurred by chance or poor experimental design, with many researchers calling menstrual synchrony a methodological artifact.

While it may appear that periods are synchronizing, it is important to remember that not everyone has a 28-day cycle, as some range from 21-35 days. This variability allows synchronicity to vary and periods to occur at the same, or different times. 

This article was originally posted here: https://www.mcgill.ca/oss/article/did-you-know-health/menstrual-synchrony

How Do Veterinarians Die? (McGill OSS)

4 minute read

I wouldn’t blame you for thinking something along the lines of “just like everyone else,” but I’m here to tell you otherwise.

Being a veterinarian is a lot like being a human doctor. Besides the fact that both professions practice medicine, albeit on different subjects, they both require top grades and many years of school. They usually necessitate one to go into debt, to work long hours, to have extreme empathy and to be on call for days at a time.

Given their similarities, we’d expect them to have similar mortality rates and causes of death, but that isn’t the case. Veterinarians are at an extremely elevated risk for suicide.

Studies find that veterinarians are between 4 and 8 times more likely to kill themselves than the general population.  A study of 1,551 American vets from 1966-1977 found a greater than 100% increase in suicides, and a 2012 Canadian Veterinary Medical Association survey found that 19% of respondents had seriously considered suicide, with 9% having made attempts. These risks seem to exist for vets around the world.

But why though? These high rates don’t seem to be mirrored in their human-treating counterparts (though some studies do find the rates of suicide in physicians elevated, but to a lesser extent), and appears to directly oppose the correlation between lowered mortality rates and graduate degrees.

Read the entire article here: https://www.mcgill.ca/oss/article/health/how-do-veterinarians-die

The Lowdown on Double Joints (McGill OSS)

1 minute read

Are you double jointed? If not, you probably know someone who is, because this relatively common condition occurs in 10-25% of the population! Technically, the term for ‘having super flexible joints that made you popular on the playground as a kid’ Is hypermobility, and it’s characterized by having shallow joints and flexible ligaments or cartilage. In the vast majority of people, having hypermobile joints is not dangerous, except if they use them to scare other kids.

However, in a minority of hypermobile people, symptoms beyond just increased flexibility can develop, such as joint pain, increased rates of fractures or sprains, fatigue or an increased susceptibility to conditions like whiplash. In cases where symptoms like these do occur, the person is said to have Joint Hypermobility Syndrome. Another condition however can lead to symptoms almost indistinguishable from Joint Hypermobility Syndrome, something called Ehlers-Danlos Syndrome (EDS).

EDS is caused by a genetic mutation that causes defects in either the structure or processing of collagen (the main structural protein of our bodies, making up 25-35% of all proteins) or other proteins that interact with collagen in connective tissue. EDS affects roughly 1 in every 5000 people and can cause less serious effects like chronic pain and easy bruising, or more serious effects like osteoarthritis or aortic dissections (when blood pools between layers of the aortic wall). EDS exists in a few different forms (7 actually), with the hypermobility form affecting approximately 1 in every 10 000 people. This hypermobility form of EDS is functionally undifferentiable from Joint Hypermobility Syndrome. Both conditions have the same diagnosis criteria, and treatment recommendations, and not even a genetic test can identify which syndrome a patient has. Due to this conflation, most experts currently recommend thinking of Joint Hypermobility Syndrome and hypermobility EDS as 1 condition, until a way to distinguish them can be found.

Article originally posted here: https://www.mcgill.ca/oss/article/did-you-know/double-joints