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Question of the Week / Re: QotW - 24.11.22 - Why are boat propellers at the rear?

« on: 09/01/2025 13:14:41 »

when a boat accelerates, the prow rises so if the propeller were at the front it would have trouble staying in the water. As well, with a planing hull (one that rises with speed and reduces the wetted surface) only the lower portion of the leg of the outboard motor and a bit of the hull are actually touching the water at high speed.
When is a front mounted propeller useful on a boat? when you have a propeller mounted on a swiveling pod for better steering in tight areas or to offer better control during cross winds. Many or most cruise ships use this system.

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Physiology & Medicine / Re: Is There Any Safe Amount Of Smoking?

« on: 09/01/2025 13:06:44 »

This string reminds me of the sad final years of the great writer Sigmund Freud. He was fond of smoking cigars as the tobacco enabled him to concentrate on his writings. When he discovered a lump in the roof of his mouth and knew it was a tumor, he declined to give up smoking as he decided completing his volumes on psychoanalysis was more important than living a longer life, so he continued to smoke cigars and write, and to suffer further surgeries to remove more tumors.
I believe tobacco is a mixed blessing: the nicotine is a great stimulant of the mind but when delivered as smoke into the lungs it inevitably causes damage that exceeds the body's capacity to heal.

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Physiology & Medicine / Re: Why Is There No Point For Taking Supplements?

« on: 09/01/2025 12:55:55 »

I simply take vitamins and a few supplements before a long run and record which ones make a difference. Interestingly, vitamins B6+B12 make me more talkative, NAD+ gives me more endurance, and Niacin calms me. Vitamin D3 helps on some days but not on others. None of the other common supplements make any significant difference. I conclude then my diet is deficient in B vitamins.

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Physiology & Medicine / Re: Is Aspartame Safe And Healthy To Eat?

« on: 09/01/2025 12:46:43 »

Many years ago I found myself at a party populated mostly by alternative health practitioners and anti-science thinkers. One lovely lady, a yoga instructor I recall, was giving a lecture on the dangers of artificial sweeteners and mentioned aspartame as being poisonous because it is turned into methanol and formaldehyde during digestion. And how does she know this? It was told to her by someone who knows this stuff -- an ambulance driver. So I checked Wikipedia for clarification and it turns out yes, digestion turns aspartame into some toxic substances but in such small quantities as to be negligible to any healthy person. Here is the quote from Wikipedia:
Aspartame is rapidly hydrolyzed in the small intestine by digestive enzymes which break aspartame down into methanol, phenylalanine, aspartic acid, and further metabolites, such as formaldehyde and formic acid.[10][51][52] Due to its rapid and complete metabolism, aspartame is not found in circulating blood, even following ingestion of high doses over 200 mg/kg.

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Physics, Astronomy & Cosmology / Am I safer on Mars?

« on: 05/01/2025 08:34:58 »

If I worry about an asteroid hitting earth and killing everyone, including me, are my odds better if I hitch a ride from Elon Musk and move to Mars? On the one hand, the Earth has a stronger gravitational attraction to asteroids, but Mars is much nearer to the asteroid belt. Is there a clear winner here?

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Plant Sciences, Zoology & Evolution / Re: Could we eat wood?

« on: 04/01/2025 08:12:21 »

So termites have bacteria in their guts that digest the normally indigestible cellulose. So what happens if we put some of those microbes into our GI tract ? will they produce sugars that we can digest?

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Physiology & Medicine / Re: Can Coffee Or Tea Ever Really Go Bad?

« on: 04/01/2025 08:05:06 »

Coffee suppliers suggest keeping roasted coffee beans in dark cool storage as oxygen and sunlight will cause degradation.
As for fungus, I believe coffee was roasted either to kill the fungus or at least hide the taste of mold, or it was roasted before shipping so the mold wouldn?t find nutrients and moisture.

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Physics, Astronomy & Cosmology / Re: What are the physics of brakes?

« on: 04/01/2025 07:58:11 »

The rotating brake disk cools by airflow entering near the axle and flowing through the vents that are cast into the iron. Sometimes holes are punched or drilled into the disk to aid cooling and to help dissipate water, but sometimes they create sounds similar to woodwind.
The heat is ideally restricted to the pad and rotor and some manufacturers use a calliper piston made of phenolic material instead of iron to protect the brake fluid from reaching its boiling point.

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Geology, Palaeontology & Archaeology / Re: Why does Earth have tectonic plates?

« on: 31/12/2024 22:13:25 »

I suspect the earth has a more dynamic composition than does Venus because of the widely held idea that a large body crashed into the early earth and that kinetic energy threw off enough material to coalesce into our moon. The combination of heat from the impact and the gravity of the moon pulling on the crust give our world the moving crustal plates.

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Geology, Palaeontology & Archaeology / Re: Why is the Congo so rich in Cobalt?

« on: 31/08/2023 03:11:25 »

My first thoughts are either the cobalt is part of an iron meteorite (is there substantial nickel and iron associated with it?) or the orogeny of the African plate is in that same area and so some deep ore from the mantle may have been exposed.

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Chemistry / Re: Silicon based Life?

« on: 18/05/2023 03:26:31 »

The nearest thing to a silicon life form is the diatomaceous plankton in the sea. While the cellular contents are conventional carbon-backbone chemistry, they are enclosed in a glass-like shell of silicon dioxide. So, with the abundance of chemicals and UV light from the sun, there may be some interesting chemistry going on between the cell contents and the glassy enclosure. It could be a step towards understanding how and where a novel life form may be found.

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Question of the Week / Re: QotW - 22.08.22 - Why is it recommended to drink coca cola after swimming?

« on: 18/05/2023 03:19:40 »

I've never drank coca cola after a swim, but while running the marathon in Greece in 2018 Coca Cola was available at the drink stations along the route. Feeling curious, I grabbed one and spit it out after a couple of swallows. Definitely not recommended for curing runner's cramps or dehydration!

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Plant Sciences, Zoology & Evolution / Re: Where would I find King Kong?

« on: 18/05/2023 03:15:48 »

coincidentally, I saw an article about the largest gorilla known to archeology. It was a giant that lived in southern China! So perhaps there may be an undiscovered island near China that is home to this relic from the past? Ha Ha.

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Plant Sciences, Zoology & Evolution / Where would I find King Kong?

« on: 15/05/2023 15:18:15 »

While enjoying the totally fictional King Kong remake, I wondered if I were to get funding to find the real Skull Island with its giant gorilla, where would I look? Climate has something to do with animal size, such as the largest bears are found in the arctic and the smallest bears live in the tropics. But living on an island makes for small wooly mammoths and large rodents. Besides, great apes tend to be mostly vegetarian and would more likely be found in rain forests than in deserts or swamps. Any suggestions?

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Physiology & Medicine / Re: What are the harmful effects of Vaping?

« on: 10/11/2021 02:14:48 »

Two issues here.
1. the labels on the vaping products are often not truthful. Remember they are often made by people who do not read English.
2. any time you inhale smoke you introduce carbon monoxide to your lungs and into your bloodstream. Bad idea!

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Physiology & Medicine / Re: When did sugar diabetes become plain old diabetes?

« on: 10/11/2021 02:11:17 »

Sugar diabetes is a term that combines Latin with English incorrectly. "diabetes" translates roughly as "across sugar" from the diagnosis of the condition was made by tasting the patient's urine for the presence of a sweet flavor. So, "sugar" is redundant in the term. Similarly, Pizza-Pie and 5 AM in the morning.

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Physiology & Medicine / Re: Can a man have two working penises?

« on: 10/11/2021 02:06:41 »

Not impossible since people are born with pieces of a twin who was absorbed during the pregnancy, commonly an extra limb.
Could a second penis be as functional as the other? Depends on the nerve supply and whether its urethra is routed to the bladder and so forth.

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General Science / Can Medicine solve Global Warming?

« on: 10/11/2021 01:55:36 »

While everyone seems concerned about shutting down fossil fuel combustion and the meat industry, I recall hearing an easier solution lies in the field of medicine. Is it true that if we offered birth control pills free of charge to the world's population, then our population growth will slow then decline after several years, thus reducing our needs for more energy, steel, concrete, and deforestation.
Is this just talk or is there some research behind this idea?
I cannot find the source.

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Physiology & Medicine / Re: What medicines can relieve Irritable Bowel Syndrome (IBS)?

« on: 12/10/2021 21:37:53 »

I think the surgical treatment involves removing that portion of intestine that is inflamed or damaged.

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Physiology & Medicine / Re: Are cold baths good for your health?

« on: 12/10/2021 21:32:01 »

The BBC has a very good interview with professor Mike Tipton on this topic. Here's a link to a published article on the science of cold water immersion and swimming.
https://physoc.onlinelibrary.wiley.com/doi/full/10.1113/EP086283