Author Topic: Episode #701  (Read 1262 times)

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Offline Steven Novella

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Episode #701
« on: December 15, 2018, 12:32:30 PM »
Interview with Susan Gerbic; Guest Rogue Brian Trent; What’s the Word: Philopatry; News Items: Release Active Drugs, Voyage 2 Update, Fast Radio Bursts Alien Hypothesis, China’s Moon Mission, The Chickenocene; Who’s That Noisy; Science or Fiction
Steven Novella
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Offline bachfiend

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Re: Episode #701
« Reply #1 on: December 15, 2018, 07:32:15 PM »
Bugger it... yet another book to read.  ‘Ten Thousand Thunders’ starts off very well, although I’m disappointed its first sentence isn’t ‘It was a dark and stormy night.’ 
Gebt ihr ihr ihr Buch zurück?

Offline Belgarath

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Re: Episode #701
« Reply #2 on: December 15, 2018, 08:07:50 PM »
Beat me by seconds on WTN!

Grrr.  :(
#non-belief denialist

Offline Isranner

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Re: Episode #701
« Reply #3 on: December 16, 2018, 02:27:24 AM »
…Science or Fiction [ Item #3 A recent study finds that introductory biology textbooks spend more time discussing insects than any other major group of animals. https://www.sciencedaily.com/releases/2018/12/181212071751.htm ]

— Centipedes aren't insects, so perhaps those textbooks should spend more time discussing insects so that students could at least be able to tell insects and other arthropods apart.

I don't think the reason for which those introductory biology textbooks devote so little discussing insects has much to do with cultural bias against insects. Those same textbooks give much more coverage to different kinds of worms even though they aren't particularly appreciated in Western culture either.

In my opinion, the explanation lays in the fact that those textbooks try to include a large variety of different organisms and body plans, whereas insects, despite their large numbers and large number of species, share with other arthropods the same basic body plan. On the other hand, those textbooks try to teach the fundamentals, try to show the basic organisation of the bodies of different organisms and how they carry out the basic bodily functions: germ layers (ectoderm, endoderm, mesoderm), cell layers (endothelium, mesothelium, epithelium), body cavities (coelom, archenteron), orifices (blastopore, mouth, anus, nephridiopores), cell types, tissues, organs, systems (reproductive, nervous, digestive, excretory, circulatory, immune), types of muscle, forms of locomotion, etc., so they preferentially focus on simple organisms in which those particularities are already apparent (e.g., in different kinds of worms), whereas insects are already rather complex organisms and quite derivative/modified from the primitive body organisation of basal organisms, so they wouldn't make good models to explain the fundamentals.
« Last Edit: December 16, 2018, 02:32:02 AM by Isranner »

Offline PatrickG

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Episode #701
« Reply #4 on: December 17, 2018, 11:18:05 AM »
No: a single leaf does not “power” 100 LED lights.

My skeptical alarm bells went off for Science-or-fiction item #1: It suggests that plant leaves generate abundant energy for LED lighting. That is false.

The word “power” is used in a non-scientific and deceptive way here. Power should be expressed in Watts; energy in Joules or Watt-hours. In this case power seems to mean just “we saw a tiny flicker of light”.

Sure, the plant leaf movement generates a voltage. But that Voltage by itself is not power. Voltage multiplied by current is power. The article makes no reference to the current nor the actual energy harvested from leaves.

A few Milliwatts are needed to light op a small indicator LED: 1.8V at 2mA. To use a LED as a light source hundreds of Milliwatts are typical. These plant leaves likely generate orders of magnitude less power than either of those.

That is no surprise as it takes so little energy to move the leaves by blowing a little wind. Compared to a windmill these are likely terribly inefficient energy converters.

Also the 100 LED bulb number is highly questionable. The forward voltage of an LED is between 1.8V and 3V. If bending the leaves produces 150V, that might be enough for a series connection of 83 LED at best. I also seriously doubt whether the flicker of 100 LEDs is from a single leaf: I see them urging a bunch of leaves in parallel.

I was not able to read the original articles. Based on what I read in the abstract and the movie they connected some electrodes and demonstrated some voltage. The fact that no power and conversion efficiency are mentioned is either amateurish or deliberately deceptive.

Movie of the research:
« Last Edit: December 17, 2018, 05:18:58 PM by PatrickG »

Offline Ah.hell

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Re: Episode #701
« Reply #5 on: December 17, 2018, 02:15:15 PM »
What Patrick said, during the whole explanation I was silently screaming, "what about power and current?"

Offline swan

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Re: Episode #701
« Reply #6 on: December 17, 2018, 03:03:23 PM »
Based on what I read in the abstract and the movie they connected some electrodes and demonstrated some voltage. The fact that no power and conversion efficiency are mentioned is either amateurish or deliberately deceptive.

This sounds like a job for EEVBlog, if we can ever get hold of actual numbers or a peek at the testing methods and conversion circuit. For now maybe I'll sew wires into my flannel pajamas and satin sheets, then hang them together on the clothesline with a voltmeter attached. Maybe that will have about the same net effect. ;)

Offline Mr. Beagle

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Re: Episode #701
« Reply #7 on: December 17, 2018, 03:38:15 PM »
I have been tracking every time I hear or see "homeopathic" in an advertisement or pharmacy item, and lately all I ever see is this label placed on some herbal medicine or another, rather than being used in the "dilution" sense. Does this mean these supplement makers are guilty of "false advertising" for improperly tagging their pills with a characteristic that is itself mythical?

My ethical brain is so confused!
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Offline daniel1948

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Re: Episode #701
« Reply #8 on: December 17, 2018, 06:25:18 PM »
PatrickG beat me to it: The item was reported so badly I’d be ashamed of it. Voltage is not what powers a light. You need current. You can expose yourself to a million volts, and if the current is low enough, you’ll hardly notice it. The leaves may have produced enough voltage for the LEDs but there’s no way one leaf produced enough current to do much of anything.

Further, the rogues royally screwed up when they suggested a house plant could light your home. In my home, the air circulation would be inadequate to move a leaf enough to do anything. You could set up an electric fan to blow on the plant to produce a tiny amount of electricity. And that would be just like those perpetual motion machines that use a battery to power a motor that runs a generator to charge the battery.

I call bogus on that SoF item.
Daniel
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Offline daniel1948

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Re: Episode #701
« Reply #9 on: December 17, 2018, 06:29:44 PM »
I lived for a while with a family in Mexico. At one time they had gotten some homeopathic pills for the little girl of the family, and her teen-age uncles were eating the pills because, being sugar, they are candy.

I was irrationally torn between being upset because the uncles were eating the pills meant for the little girl, or because they were giving her homeopathic sugar pills in the first place. In the end I said nothing because I think the mother and grandmother knew perfectly well that the pills were just sugar.
Daniel
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Online arthwollipot

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Re: Episode #701
« Reply #10 on: December 17, 2018, 06:31:18 PM »
Jay briefly mentioned that he was an optimistic nihilist.

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Offline daniel1948

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Re: Episode #701
« Reply #11 on: December 17, 2018, 07:51:27 PM »
My mother called herself a cheerful pessimist. The world is going to hell in a hand basket, so we might as well be cheerful about it. But since a rational look at things shows that we are indeed going to hell in a hand basket, I call this attitude cheerful realism. I’m a realistic cheerful cynic. The world is going to hell in a hand basket and I don’t care any more. I’m spending what little time I have left having fun.
Daniel
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Offline CarbShark

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Re: Episode #701
« Reply #12 on: December 17, 2018, 11:51:04 PM »
PatrickG beat me to it: The item was reported so badly I’d be ashamed of it. Voltage is not what powers a light. You need current. You can expose yourself to a million volts, and if the current is low enough, you’ll hardly notice it. The leaves may have produced enough voltage for the LEDs but there’s no way one leaf produced enough current to do much of anything.

Further, the rogues royally screwed up when they suggested a house plant could light your home. In my home, the air circulation would be inadequate to move a leaf enough to do anything. You could set up an electric fan to blow on the plant to produce a tiny amount of electricity. And that would be just like those perpetual motion machines that use a battery to power a motor that runs a generator to charge the battery.

I call bogus on that SoF item.
I’ll have to Listen again but I believe the point was that it would produce enough wattage (voltage and current) for only a brief flash.


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Offline PatrickG

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Episode #701
« Reply #13 on: December 18, 2018, 09:06:56 AM »
....
I call bogus on that SoF item.
I’ll have to Listen again but I believe the point was that it would produce enough wattage (voltage and current) for only a brief flash.

Steve is great in producing Science-or-Fiction items. This item, however, was a skeptical fail, both in the way it was formulated as well as the quality of the underlying work. This is verbatim how it was formulated:

Quote
Researchers have found a way to harvest electricity directly from plants, so that a single leaf can generate enough voltage to power 100 LED lights.

To any casual reader this suggests that a potential solution to our energy problem lies in harvesting electricity from plant leaves. After all, it “powers 100 LEDs” from a single leaf. 100 LEDs is more convincing than 1 LED, right?

There is a widespread public misperception that a higher voltage is somehow more powerful. Try shopping for a cordless drill at Home Depot. All ads prominently show volts, but never power or durability. You are made to believe that 18 Volts is better than 12V.

It would be truly relevant to know whether the energy harvested from leaves is enough for a tiny internet-of-things device. It would be interesting to know whether this connection is reliable. And it would be interesting how this compares to other means of harvesting energy from wind.  None of those questions are answered by this work.
« Last Edit: December 18, 2018, 09:12:11 AM by PatrickG »

Offline daniel1948

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Re: Episode #701
« Reply #14 on: December 18, 2018, 09:47:12 AM »
There is one respect in which higher voltage is better: lower voltage requires heavier wiring for the same amount of wattage because it necessitates higher current. But this is irrelevant to the discussion at hand where we’re talking about powering lights.

Steve should have said that the leaves produced enough wattage for X. Of course expressed this way, it would have been the fiction. Or he should have said that a leaf of X size produced Y voltage and Z amperes.
Daniel
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"Anyone who has ever looked into the glazed eyes of a soldier dying on the battlefield will think long and hard before starting a war."
-- Otto von Bismarck