Posts about science explained

Science Explained: Momentum For String of Metal Beads

Fun video with an explanation of the physics behind what might seem like the surprising action shown in the video.

Related: The Science Behind Hummingbird FlightScience and Optical IllusionsGravity and the Scientific MethodHow do Plants Grow Into the Sunlight?

How Do You Lose Weight While You Sleep?

In this interesting webcast, Derek Muller, (a physics teacher in Perth, Australia) explores how much weight you lose while you sleep. As physics teacher he asks the sensible question: how do you lose weight while you sleep, what weight do you lose?

His conclusion is you lose weight through perspiration, water vapor in your breath and expelling carbon dioxide. Losing the water weight is pretty straight forward. The process of adding carbon to the breath we expel is not something I thought of. He calculates that we lose about 100 grams of carbon during a night of sleep. In his somewhat scientific experiment (measuring himself for several days) he lost about 150 more grams, which he attributes to water vapor and perspiration.

It seems to me the amount of carbon we lose during sleep is probably much more consistent than the amount of water weight we lose (both between people and variation between different days).

Related: Can You Effectively Burn Calories by Drinking Cold Water?CDC Urges Reducing the Amount of Salt We EatWhy is it Colder at Higher Elevations?How Caffeine Affects Your BodyWhy Does the Moon Appear Larger on the Horizon?

Building A Better Bed Bug Trap Using Bean Leaves

Building A Better Bed Bug Trap

An old folk remedy involving hairy bean leaves strewn around the bedroom may have a new life as a modern bed bug trap, according to new research from the University of California, Irvine and the University of Kentucky.

Although its mechanisms weren’t known at the time, the tactic dates back to at least 1678, when the English philosopher John Locke wrote of placing kidney bean leaves under the pillow or around the bed to keep bed bugs from biting as he traveled through Europe.

In the early twentieth century, the approach was also common throughout the Balkans, according to a 1927 report from the Imperial and Royal Austro-Hungarian Army. That report suggested the leaves stunned the bloodsucking bugs as they traveled from hiding places to their sleeping hosts during the night; in the morning, the bug-covered leaves were removed and burned.

“The inconvenience of bean leaves is that not everyone wants them scattered around their bed room.” Synthetics mimicking the surface of the bean leaf, however, could be placed “as a ring around the bed legs, a floor mat at the door, a strip on the bed board, it could be something one put’s in one’s suitcase,”

Very cool. The chemical assault on bed buds is failing all over the world. A new vector to assist in the fight against bed bugs will be most welcome. It is interesting to learn the scientific reasons that explain why some folk remedies work.

Related: Bed Bugs, Science and the MediaAntibiotics Breed Superbugs Faster Than ExpectedPigs Instead of Pesticides

Human Gene Origins: 37% Bacterial, 35% Animal, 28% Eukaryotic

The percent of human genes that emerged in various stages of evolution: 37% bacterial, 28% eukaryotic, 16% animal, 13% vertebrate, 6% primate. The history that brought us to where we are is amazing. Eukaryotes include animals, plants, amoebae, flagellates, amoeboflagellates, fungi and plastids (including algae). So eukaryotic genes are those common to us and other non-animal eukaryotes while those classified as animal genes are shared by animals but not non-animal eukaryotes.

We are living in a bacterial world, and it’s impacting us more than previously thought by Lisa Zyga

Bacterial signaling is not only essential for development, it also helps animals maintain homeostasis, keeping us healthy and happy. As research has shown, bacteria in the gut can communicate with the brain through the central nervous system. Studies have found that mice without certain bacteria have defects in brain regions that control anxiety and depression-like behavior. Bacterial signaling also plays an essential role in guarding an animal’s immune system. Disturbing these bacterial signaling pathways can lead to diseases such as diabetes, inflammatory bowel disease, and infections. Studies also suggest that many of the pathogens that cause disease in animals have “hijacked” these bacterial communication channels that originally evolved to maintain a balance between the animal and hundreds of beneficial bacterial species.

Scientists have also discovered that bacteria in the human gut adapts to changing diets. For example, most Americans have a gut microbiome that is optimized for digesting a high-fat, high-protein diet, while people in rural Amazonas, Venezuela, have gut microbes better suited for breaking down complex carbohydrates. Some people in Japan even have a gut bacterium that can digest seaweed. Researchers think the gut microbiome adapts in two ways: by adding or removing certain bacteria species, and by transferring the desired genes from one bacterium to another through horizontal gene transfer. Both host and bacteria benefit from this kind of symbiotic relationship, which researchers think is much more widespread than previously thought.

We want badly for the message in ‘Animals in a bacterial world,’ to be a call for the necessary disappearance of the old boundaries between life science departments (e.g., Depts of Zoology, Botany, Microbiology, etc.) in universities, and societies (e.g., the American Society for Microbiology, etc.). We also want the message disseminated in college and university classes from introductory biology to advanced courses in the various topic areas of our paper.”

Very cool stuff. This amazing facts scientists discover provide an amazing view of the world we live in and how interconnected we are to other life forms in ways we don’t normally think of.

Related: People’s Bodies Carry More Bacterial Cells than Human CellsMicrobes Flourish In Healthy PeopleTracking the Ecosystem Within UsForeign Cells Outnumber Human Cells in Our BodiesBacteria Beneficial to Human Health

How to Walk on Ice

infographic explaining how to walk on ice - walk like a penguin

Infographic by Tablet. Falling on ice leads to many injuries and even 60 deaths a year in the USA (about the number that will die due to tornados). The graphic encourages thinking like a penguin. Penguins walk well on ice (in some ways) and they also fall well.

Seeking to keep your weight well supported (short strides) is wise (and sliding instead of picking up your feet can help). Falling well is also important. It is basic physics, you want to lower your center of gravity if you are start to slip and avoid any excessive force (so sliding is better than trying to stick out your hand and support all your weight). The elderly are especially susceptible to injuries – avoiding taking direct shocks to the wrist, knees or hips is wise). It does seem kind of silly to learn how to fall but it is very helpful in avoiding injuries.

On sidewalks if you are going to fall and there is snow piled up off the sidewalk, falling into the pile of snow may well be softer than falling directly onto the sidewalk.

On ice you have lower friction so strategies that require friction are not useful – quick moves often rely on very sturdy bases (which are based on the friction of our shoe on for example concrete [which normally is good – though business shoes are not very good] and on ice [where it is very poor – sliding and gradual moves are better]).

Related: Falling SafelyMinistry of Silly WalksMake Crosswalks More VisibleWhy Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was DimmerScience Toys You Can Make With Your Kids

Why is the Sky Dark at Night?

The answer isn’t quite as simple as it seems. I find the wording in the video a bit confusing.

The point I believe, is that the sky is dark instead of light. But not that the brightness would be huge (so for example, you couldn’t necessarily read my book outside just by starlight). The light would be very faint, it is just that it would be lightish instead of blackish, due to the reasons explained (redshift etc.). At least that is my understanding.

Related: Why is it Colder at Higher Elevations?Why Does the Moon Appear Larger on the Horizon?Why is the Sky Blue?Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer

Science Explained: Cool Video of ATP Synthase, Which Provides Usable Energy to Us

This webcast shows animations of ATP synthase structure and the mechanism for synthesizing ATP. Biology is incredibly cool. Too bad they didn’t have stuff like this when I was in school, instead biology was mainly about memorizing boring lists of stuff.

ATP (adenosine tri-phosphate) transports chemical energy within cells. When one of the phosphates is released by ATP energy is given off (and ATP becomes ADP (adenosine di-phosphate) + Pi (inorganic phosphate). And then the synthase structure can then turn it back into ATP to be used again.

The human body, which on average contains only 250 grams of ATP, turns over its own body weight equivalent in ATP each day.

Related: ATP synthase lecture notes University of IllinoisWebcast on the makeup and function of eukaryotic cellsScience Explained: PhotosynthesisVideo showing malaria breaking into cell

The Science Behind Hummingbird Flight

Aerodynamics of the hovering hummingbird

Hummingbirds and insects have evolved for sustained hovering flight from vastly different ancestral directions, and their distinct phylogenies underlie the differences in their aerodynamic styles. In all other birds—and, presumably, hummingbird ancestors—the downstroke provides 100% of weight support during slow flight and hovering. Given that many birds possess the mass-specific power (using anaerobic metabolism) to hover for short periods, the selective pressure on hummingbird ancestors was probably for increased efficiency (resulting in stiff wings with greatly simplified
kinematics), and an upstroke muscle (the supracoracoideus) that makes the recovery stroke rapid, while contributing enough to the hovering power requirements to allow the downstroke muscle (the pectoralis) to operate within its aerobic limits.

In other words, this pseudosymmetrical wingbeat cycle is good enough, and although hummingbirds do not exhibit the elegant aerodynamic symmetry of insects, natural selection rewards ‘good enough’ as richly as it does our aesthetic ideals

Related: Praying Mantis Attacks HummingbirdFriday Fun: Crow Sledding, Flying Back Up and Sledding Down AgainBird Using Bait to Fish

Great Webcast Explaining the Digestive Systems

You will learn things like why it is so important to chew your food well (increase the surface area for enzymes to get at the food). Our bodies also have adapted to provide a huge surface area for the digestive system to work; the small intestine alone has a surface area of 250 square meters (larger than the size of most apartments). Your small intestine is 4.5 to 10.5 meters long.

Related: Staphylococcal Food PoisoningEnergy Efficiency of DigestionTracking the Ecosystem Within UsWaste from Gut Bacteria Helps Host Control Weight

The Appendix Serves As a Reservoir of Beneficial Bacteria

This is an interesting explanation for the purpose of the appendix.

The appendix does have a use – re-booting the gut

The US scientists found that the appendix acted as a “good safe house” for bacteria essential for healthy digestion, in effect re-booting the digestive system after the host has contracted diseases such as amoebic dysentery or cholera, which kill off helpful germs and purge the gut.

This function has been made obsolete by modern, industrialised society; populations are now so dense that people pick up essential bacteria from each other, allowing gut organisms to regrow without help from the appendix, the researchers said.

But in earlier centuries, when vast tracts of land were more sparsely populated and whole regions could be wiped out by an epidemic of cholera, the appendix provided survivors with a vital individual stockpile of suitable bacteria.

Related: Microbes Flourish In Healthy PeopleBeneficial BacteriaForeign Cells Outnumber Human Cells in Our Bodies

The Chemistry of Fireworks

The video features John A. Conkling, Ph.D., who literally wrote the book on fireworks — he is the author of The Chemistry of Pyrotechnics.

The earliest documentation of fireworks dates back to 7th century China.

A Syrian named Hasan al-Rammah wrote of rockets, fireworks, and other incendiaries, using terms that suggested he derived his knowledge from Chinese sources, such as his references to fireworks as “Chinese flowers”.

Chinese fireworks began to gain popularity around the mid-17th century.

Related: Cooking with Chemistry, Hard CandyThe Chemistry of CookingVideo of Briggs-Rauscher Oscillating Chemical Reaction

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