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Plant Sciences, Zoology & Evolution / What is the Origin of Naked Clams (Shipworms)?

« on: 29/09/2024 11:22:40 »

On a recent Naked Scientists podcast, there was an interview about eating "naked clams", otherwise known as shipworms.

Chris asked when these evolved, given that long-distance sea voyages have really only taken off since around the year 1500.
- In Townsville I saw an example of the steps taken in the 1700s to prevent shipworm damage: cover the entire hull with copper.

I have recently visited the Australian Dinosaur Trail, in central Queensland.

The area where Richmond is now located was once under an inland sea, and they have many marine fossils. Most of the local fossils on display were dated at around 100 million years ago.
- One of the fossils on display at Kronosaurus Korner is a log, which had apparently been washed away and floated out to sea, before sinking and becoming fossilised
- This log shows signs of severe infestation with shipworm
- So I guess the shipworms have been around as long as there have been floating logs to digest.

https://www.kronosauruskorner.com.au/

Shipworm_fossil.png (610.74 kB . 714x479 - viewed 132 times)

Shipworm_caption.png (761.54 kB . 830x497 - viewed 134 times)

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Plant Sciences, Zoology & Evolution / Why are horses cannier than we first thought?

« on: 18/08/2024 08:44:51 »

The recent Naked SCientists story asked why are "Horses cannier than we first thought"?

It could be because they live in herds, and have to negotiate a complex pecking order (or perhaps biting and kicking order), every day.

So perhaps  it is important for a horse to recognise individuals and know how to interact appropriately with each?

https://www.thenakedscientists.com/articles/interviews/horses-cannier-we-first-thought
 

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Technology / What is the impulse response of the world?s economy?

« on: 23/07/2024 08:02:09 »

The recent Microsoft/Clodstrike outage gave a 1-day kick to the world?s economy.

It was felt immediately at airports and ATMs.

After a few days, it is showing up in empty supermarket shelves

I suspect that the flow-on effects will continue reverberating for weeks or perhaps months?

In electrical engineering terms, this is the impulse response of a system.

Will this measure the impulse response of the world economy?

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New Theories / New Maths? (Orders of Magnitude)

« on: 14/01/2024 11:07:59 »

An idea for a way of teaching maths that is better related to human senses. This was split off from:
https://www.thenakedscientists.com/forum/index.php?topic=86686.msg719574#msg719574
All comments are welcome! Feel free to pass these ramblings on to real educators!

Human Senses
Most human senses need to span many orders of magnitude in sensitivity, so the response tends to be logarithmic, rather than linear (linear would imply 50% is half-way).

I think that kids would find maths and science more relatable if we talked in units they can feel and relate to - logarithmic units
-   Sound intensity is measured in dB (logarithmic), sound frequency is measured in octaves (logarithmic), brightness in astronomy is measured in magnitudes (logarithmic)
-   Bicycle gears form a geometric progression
-   Hardness is measured on Moh's scale (logarithmic except for diamond)
-   Earthquake strength uses the Richter scale, and wind speed uses the Beaufort scale (both logarithmic)
-   Electronic component values fall on a logarithmic scale
- I suspect that things like touch, smell and taste would also have a logarithmic response
- Psychologists have even shown that abstract concepts like "value" or "wealth" also have a logarithmic response
- The Metric System and Scientific notation are both based on a logarithmic scale, with units like meters and grams, and their derived units of millimeters, kilometers, kilograms and tonnes.

Number Concepts
Subitizing: I think that a natural place to start with numbers is with subitizing, the innate ability to count 0 to 4 or 5 objects at a glance. Learning to relate the name and visual representation of the digit to the quantity of objects is important (and 0 is vital, as the thing kids feel most strongly is if someone else gets 1 lolly, and they get 0).

Large Orders of Magnitude: 0, 1, 10, 100, 1000: When I was a kid, we were given number blocks, where "1" was represented by a small white cube.
-   10 of these in a line represents 1 order of magnitude (and 1 dimension)
-   100 of these in a 10x10 plate represents 2 orders of magnitude (and 2 dimensions)
-   1000 of these in a 10x10x10 cube represents 3 orders of magnitude (and 3 dimensions)

This should be supplemented by kinesthetic experiences like:
-   Walk a metre: A kilometre is 1000 times farther
-   Walk 10m: A kilometre is 100 times farther
-   Walk 100m: A kilometre is 10 times farther
-   Walk 1 km
-   And similar sensory experiences with mass, brightness, sound intensity, frequency, and smell (taste might be a bit more of risk due to potential allergies?)
- Wealth comparisons like kids who survive on $1/day, $10/day, $100/day and $1000/day
-   Given random quantities of each, which is it closer to? (estimating orders of magnitude, bearing in mind that 3 is closer to mid-way on a logarithmic scale)

Small Orders of Magnitude: 1, 0.1, 0.01, 0.001, 0: Here you could start with the large cube, and the plate and line represent fractions of the whole (whole apple, whole bottle of water, etc)
This should be supplemented by kinesthetic experiences like:
-   Take a metre of string, compare to 10cm, 1com and 1mm of string
-   Take a kilo of sand, compare to 100g, 10g and 1g
-   Take a litre of water, compare to 100ml, 10ml, 1ml
-   Compare a walk of 1km to 100m, 10m, 1m
-   Compare $10, $1, 10c, 1c
-   Given random quantities of each, which is it closer to? (estimating orders of magnitude, bearing in mind that 3 is closer to mid-way on a logarithmic scale)
-   And similar sensory experiences with brightness, sound intensity, frequency, and smell
-   Not forgetting 0 of each, which is a child's ultimate reference point! (and the control value in an experiment, eg no sound, no light, no money)

Simple Arithmetic and counting further: Based on Subitization, what happens if you add one, or subtract one, take all away or add another group the same size?
-   When adding 4+4, you quickly run into answers that are beyond subitizing
-   This should lead to learning numbers from 0 to 10
-   And the more laborious process of counting with 1-to-1 correspondence (which it takes kids a while to achieve)

The leading digits: After the orders of magnitude, the next most important numbers are:
-   Nx 3 (the sensory middle of 1 & 10), 30, 300 [Mathematically 10^1/₂  = 3.16, but use 3 as an integer]
-   Nx 2 & 5 (break the decade into 3 ranges), 20, 50, 200, 500 [10^1/₃=2.15 & 10^2/₃=4.64, but use 2 & 5 as integers]
-   Doubling 1, 2, 4, 8 (especially important in music and computers)
-   N x 9, the last digit to be covered (and least useful, being almost imperceptibly different from 10), 90, 900. Immunise against the shopper's fallacy: The gap between 9 & 10 is much smaller than between 1 & 2!

Next most important numbers: According to Benford's law, when looking at numbers in physical laws, finance and election results, about 30% of the time the leading digit will be "1" (which is why we start with the orders of magnitudes).
-   This means that the next most important numbers are between 11 & 19
-   Then fill in the gaps up to 100.
-Give the ideas of units, 10s, 100s in position notation (and digit 0)

Simple Scientific notation: Count how many orders of magnitude larger or smaller two quantities are.
Have blocks that increase in powers of 2:
-   Unit block, line of 2, plate of 4, cube of 8 = 3 dimensions
-   cube of 8, line of 2 cubes of 8, plate of 4 cubes of 8, cube of 8 cubes of 8 = 64
-   Count the powers of 2

Logic: AND, OR,NOT with computer simulation of real examples.

Fractions: Teach it with music, pies, and apples:
-   Octave 2:1; harmonies 2/3, 3/4, etc
-   For lengths, mass, volume, etc, start with 1/10 and progress to other ratios like ¹/₂, ¹/₃, ²/₃,¹/₄, ²/₄=¹/₂,³/₄, etc

Tools Required
-   Weights and liquid volumes can be easily obtained
-   Computers are easily able to present random groupings of dots, apples, oranges and coins?
-   1-1 correspondence could be helped with touch screens which make the object visibly different after you touch it and count it
-   Sound levels and sound frequencies over several orders of magnitude are easily generated on modern computers
-   Various strengths of scents tend to be single-use, but I am sure they could be produced faily easily. Ensure you go from weakest to strongest, otherwise the nose will become desensitised!
-   Computers are able to simulate simple logical combinations, but they would need to be child-relatable examples, eg assume pet = cat or dog; so an elephant is not a pet?

Potential Difficulties?
It's different! The idea of teaching 10, 100 & 1000 before teaching 9 seems radical.
Logarithmic units might be a difficult concept for existing primary school teachers to grasp

Several examples were kindly contributed by alancalverd & vhfpmr

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Question of the Week / QotW - 23.12.16 - Can you trigger nuclear Armageddon on Jupiter?

« on: 09/12/2023 20:42:36 »

...from one of our younger listeners...

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Chemistry / Are "Forever Chemicals" used in fighting bushfires?

« on: 15/05/2023 21:59:50 »

I see today that there has been a big payout by the Australian government because "Forever Chemicals" like PFAS leaked from air force fire drills onto nearby properties and waterways. These  fluorocarbons are not bio-degradeable, and are said to have many toxic effects.

When I see images of aerial fire-bombing, the water dumped from the plane is often brightly-coloured (pink is common).
- I assume that this is some sort of chemical mixed with the water - does anyone know what it is?
- Is this chemical safe to dump on our forests, wildlife and streams?

https://www.abc.net.au/news/2023-05-15/pfas-class-action-commonsettlement-reached-with-30-000-claimants/102346274

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Question of the Week / QotW - 23.05.05 - How fast does evolution happen?

« on: 06/05/2023 03:43:41 »

On today's podcast, a listener asked how long does it take a mutation to spread through a population?
In summary, the answer was: Evolution can be very fast or very slow.

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Plant Sciences, Zoology & Evolution / What other Innovation Arms Races do you know, between humans & animals?

« on: 08/10/2022 01:30:18 »

A recent story in TNS podcast talked about the innovation arms race in Sydney between cockatoos (a kind of parrot) and humans (a kind of hominin) and their wheelie bins (a kind of garbage bin).
https://www.thenakedscientists.com/articles/interviews/cockatoos-become-bin-raiding-menace

The story mentioned the lack of similar examples in the literature (apart from squirrels and bird-feeders), so I thought we could pool some ideas...

To start off: One that springs to mind is the complexity of opening garbage bins in Alaska. The bears are very good at opening garbage bins.

I heard of one ranger who said "there is an overlap between the intelligence of the brightest bears and the dumbest tourists...".

So perhaps Yogi Bear might be another documented case? (but kids cartoons are not peer-reviewed scientific literature...)

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The Environment / Has atmospheric CO2 steadily reduced over the past 140 Million years?

« on: 01/09/2022 10:41:35 »

On social media, I see claims that atmospheric CO2 has steadily reduced over the past 140 Million years, with today's 412 ppm being abnormally low.

I tried searching for information on this, but all I could find were records for <1 million years ago.

So is it an urban myth, or is there some real data around for this time period?

Thanks...

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Physics, Astronomy & Cosmology / MOVED: Dark Energy As Radiation Pressure (article)

« on: 19/06/2022 09:57:26 »

This topic has been moved to New Theories.

https://www.thenakedscientists.com/forum/index.php?topic=85000.0

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Question of the Week / Can the Earth be used as a dynamo?

« on: 28/04/2022 10:28:10 »

Linda asks: Can the spinning of the Earth be used as a source of electricity, similar to the spinning of wind turbines?

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COVID-19 / Could the BCG Tuberculosis vaccine reduce the severity of COVID-19?

« on: 22/06/2021 05:03:27 »

There are hints that countries which routinely vaccinate against tuberculosis have a lower death rate from COVID-19.
- East Germany continued BCG vaccinations long after West Germany - and the COVID death rate is significantly lower in East Germany.
- Very high COVID death rates were expected in poor tropical countries. Apart from India, rates have not been enormously high. But these same countries have high levels of BCG vaccination. (Note that the coverage of diagnosis and quality of reporting is suspect in many of these countries).
- Is this coincidence or causation?

Clinical trials are underway, but no results published yet.

For an optimistic interview with an expert (start about 2/3 of the way through): https://after-on.com/episodes-31-60/056
For a more cautious view: https://en.wikipedia.org/wiki/BCG_vaccine#COVID-19

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Physics, Astronomy & Cosmology / How do galactic jets form?

« on: 02/04/2021 09:57:15 »

Some additional analysis of data from the Event Horizon Telescope images of the M87 supermassive black hole revealed information about the magnetic fields in the accretion disk.

How do these magnetic fields propel the matter jets produced by active galactic nuclei?

See: https://scitechdaily.com/astronomers-polarized-image-shows-magnetic-fields-at-the-edge-of-m87s-black-hole/

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That CAN'T be true! / MOVED: Re: How can a question be fake news?

« on: 21/03/2021 09:30:35 »

This topic has been moved to COVID-19.

https://www.thenakedscientists.com/forum/index.php?topic=81506.0

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COVID-19 / Has Europe declared a "Vaccine BREXIT"?

« on: 28/02/2021 20:20:03 »

Recently, the heads of Germany and France have come out strongly against deploying the Oxford University/Astra-Zeneca vaccine in their respective countries.

Are there objective reasons for this, or is it just another victim of BREXIT-19?

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COVID-19 / Could a nebulizer spread COVID-19?

« on: 14/02/2021 08:36:44 »

A recent outbreak of COVID-19 in a Melbourne quarantine hotel is blamed on a quarantine "guest" using a nebulizer for asthma.

Virus apparently spread from one room to the corridor and other rooms across the corridor, as well as other parts of the hotel. And yet security video showed that people did not sneak out of their rooms.

Could the fine mist of a nebulizer spread SARS-COV2 on droplets?

Start video at 25 seconds:
https://www.abc.net.au/news/2021-02-11/how-did-a-nebuliser-contribute-to-victorias-hotel/13146434?nw=0
See: https://en.wikipedia.org/wiki/Nebulizer

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Physics, Astronomy & Cosmology / Is the Milky Way galaxy blowing bubbles?

« on: 07/02/2021 03:30:28 »

On South African phone-in radio this week, Dr Chris Smith was asked a question about giant bubbles extending above and below the disk of the Milky Way galaxy. The caller could not provide any more information, leaving the question open.

I am wondering if the caller was referring to the "Fermi Bubbles", which were discovered in 2010 by a space Gamma-Ray telescope?
- These do extend above and below the plane of the Milky Way galaxy, by about 25,000 light-years (about the same distance as between the Sun and the center of the Milky Way)
- There have been tantalizing reports from the Ice Cube neutrino telescope of unusually high-energy neutrinos coming from the general direction of the Fermi bubbles
- A more recent paper presented in mid 2020 claimed that astronomers have now been able to detect these Fermi Bubbles in visible light, which will provide far higher resolution measurements of velocity (via Doppler shift) than you can get with a Gamma-Ray telescope

Many radio galaxies had previously been observed, with elongated sources of radio emission extending from the center of the galaxy.
- This could be a polar jet emitted as a "burp" from the supermassive black hole at the center of the galaxy, after it had an oversized meal
- The Milky Way's supermassive black hole is currently rather quiet, but the presence of these Fermi Bubbles suggests that perhaps it was more active in the past, blowing large amounts of matter into space?

See: https://www.sciencedaily.com/releases/2020/06/200603120542.htm
Images: https://commons.wikimedia.org/wiki/Category:Fermi_Bubbles

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COVID-19 / Does a high prevalence of virus in the community lead to a higher mutation rate?

« on: 12/01/2021 20:14:43 »

There has been an extensive "family tree" of SARS-COV2 RNA sequences created since the Wuhan RNA sequence was leaked provided to scientists outside China.

The common statistic quoted is that "SARS-COV2 virus incurs about 1-2 mutations per month".
- This is derived by looking at the RNA sequence in 1 patient, and counting the days back to the previously recorded ancestor of that virus
- That suggests to me that if there are average of 10 people infected over a month, we would expect to see 10-20 mutations appear throughout the 30,000 bases of this RNA genome
- However, if there are an average of 1 million people infected over a month, there would be 1-2 million mutations appearing. Since the genome is only 30,000 bases long, some of these mutations would make the same change to the same base, so they would be indistinguishable

If there are more mutations, it seems to me that there is an increased chance that one of these mutations (or a combination of them) would make the virus more transmissible, or change it in ways that evade the immune system or the vaccine.

Is this a reasonable scenario?
- Does having more infected people mean that there will be more total mutations in a given month?
- Does allowing the virus to roam freely increase the chance that mutations will create a new strain that needs a different vaccine?
- Have the governments in multiple countries just destroyed the effectiveness of the vaccines of which they were so proud?

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COVID-19 / Could COVID-19 cause Psychological problems?

« on: 30/12/2020 22:20:56 »

A few instances of COVID-19 infection possibly causing psychotic episodes months later?
- Another reason to minimize infection rates until a vaccine arrives!

See: https://www.nytimes.com/2020/12/28/health/covid-psychosis-mental.html

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COVID-19 / Which COVID-19 candidate vaccines have been abandoned, and why?

« on: 11/12/2020 21:19:44 »

This week, a COVID-19 vaccine candidate from University of Queensland (UQ) and vaccine maker CSL was abandoned, even though Phase 1 safety trials showed that it was safe, and produced a good immune response to the SARS-COV-2 virus.

The reason was that this vaccine (falsely) triggered a weak positive result in commonly-used HIV tests.
- This reduces the effectiveness of AIDS testing that is vital for maintaining public health (AIDS had caused a previous, slow-burn pandemic)
- The vaccine did not contain HIV virus particles, and could not cause AIDS

The false-positive HIV result came from a "clamp" protein used to hold the SARS-COV2 spike protein in the correct shape as part of the SARS-COV2 vaccine. This clamp protein was inspired by a well-studied protein in HIV.
- The researchers were aware of this possibility, and tested for it, and included it on the approval forms signed by the participants.
- Since there were other vaccines which have passed phase 3 trials, and are proven effective against SARS-COV2 virus, they decided to abandon the UQ/CSL vaccine.

See: https://www.abc.net.au/news/2020-12-11/how-the-uq-covid-19-vaccine-induces-false-positive-hiv-results/12975048

PS: Some people have doubt about the quality of the testing used for COVID-19 vaccines, or political pressure encouraging shortcuts. Examples of cases where the the decision has been made to abandon or modify a vaccine might improve public confidence in the process and the product.