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DVD Smith
1280942.  Thu Apr 12, 2018 7:18 am Reply with quote

Quickest ever
In 1957, the record for the fastest man-made object ever recorded was broken…by a giant nuclear-powered manhole cover. [1][2][3]

The manhole cover in question was a 4ft-wide round metal plate, and was covering the top of an underground nuclear test chamber in Los Alamos, New Mexico, where the US government had recently started conducting nuclear tests underground to reduce the chance of fallout. They placed a 1-kiloton device at the bottom of the 500ft-deep cylindrical chamber, and detonated it, with a high-speed camera trained on the round metal plate covering the hole. When the device detonated, it basically turned the chamber into an enormous gun, which blasted the cover from the hole so quickly that the high-speed camera (reported to have a shutter speed of 160 frames/second [4]) only caught it on film for one frame. The scientist in charge, Dr Robert Brownlee, recorded that, from the speed of the camera and the distance visible in the photo, he calculated the speed of the plate to be “six times the escape velocity of the Earth”, which would put it in the region of 66 km/s, or 150,000 mph. [5] [6] Thermodynamic calculations performed on this website would appear to support this, as with a few assumptions they calculated a launch velocity of 56 km/s, or 125,000 mph, approximately five times the Earth’s escape velocity.

Since the incident occurred, the story has been reported over the years as “the first man-made object sent into space” due to the manhole cover’s speed, the nuclear test taking place a few months before Sputnik launched, and the fact that the plate was never found. [2][7] Brownlee disputes this, as he believes the plate would have burned up in the atmosphere, like an upwards-travelling meteor. [5] [8]

Since the space age began, more than one spacecraft has claimed to be the fastest. In summer of 2016, the NASA spacecraft Juno arrived at Jupiter, with several websites calling it “the fastest spacecraft ever”, with Jupiter’s gravity accelerating it to a calculated top speed of 165,000 mph, or 74 km/s. [9][10] However, it’s hard to compare, since all space-travel speed calculations are done using a frame of reference, usually a large gravitational body. [11] The solar probe Helios 2 officially holds the record, as measured relative to the Sun it achieved a speed of 147,000 mph, but when measured relative to the Earth (as Juno was) it reached a whopping 215,000 mph, or 96.2 km/s. The record is set to be undisputedly broken again when the Solar Probe Plus launches in July 2018, which is calculated to reach Sun-relative speeds of 450,000 mph, or 200km/s. [12]

It’s a classic trope of lots of films, TV shows and video games – pits of wet liquid-y sand that suck people in and swallow them whole. It became such a common Hollywood plot device that at its peak in the 1960s, one in every 40 films released featured quicksand in it at some point. [13] Quicksand is defined as sand (or mud or clay) that is saturated with water, to the point where the friction between the sand particles is removed and so the sand cannot support the mass of a human in the same way dry sand can. (It becomes a non-Newtonian fluid, just like custard.) [14]

In reality, the chances of quicksand “swallowing you whole”, as it were, are practically impossible. This isn’t to say it isn’t dangerous, as it can still kill you if you get stuck, but experiments have shown that you’re not gonna sink below the surface like all the films tell you; depending on the viscosity of the quicksand, you’ll either bob on the surface from the buoyancy or you’ll sink halfway and no further. [15][16][17][18]

However, so-called “dry quicksand” can absolutely swallow you whole. Dry quicksand is like regular sand, but with enough pockets of air between the sand particles that friction is removed in the same way that water saturation does. Because dry quicksand doesn’t have any water, it doesn’t have the same buoyancy effect, and so you just sink and sink. [19][20] In addition, every time you exhale, the volume of your chest reduces and the sand quickly moves to fill that space, increasing the pressure on your chest and making it much harder for you to breathe in. The existence of dry quicksand in nature is disputed, but its effects are just as visible and just as deadly in other materials – in 2002 a man in Germany was rescued from a grain silo after he fell in and started sinking into the grain, which started completely swallowing him. [14][21]

The most likely cause of death from getting stuck in quicksand is death from exposure or starvation, or drowning when the tide comes in (since most quicksand is located near water). [Klaxon: Suffocating/drowning due to sinking into the sand.] However, deaths by quicksand are still relatively rare – in 2016 the Houston Chronicle reported only one death in Texas due to quicksand in the previous five years. [22] The best advice if you get stuck is not to struggle, and try to float on the surface to spread your mass out as much as possible, and hopefully your legs will pop free. [16] If you tried to lift your legs out vertically while standing upright, you’d need to exert a force of 100,000 newtons – the equivalent of the strength needed to lift a medium-sized car. [15]

Last edited by DVD Smith on Mon Sep 17, 2018 5:16 am; edited 1 time in total

1280957.  Thu Apr 12, 2018 9:56 am Reply with quote

Hyponychium is another name for the QUICK of the fingernail - so I just read...

1280968.  Thu Apr 12, 2018 10:55 am Reply with quote

Feralcat wrote:
Hyponychium is another name for the QUICK of the fingernail - so I just read...

Nice one, sir!

And then, of course,,there is Diana Quick, an actress over whom I used to drool quite a lot in her younger days. Figuratively, of course, as i never knowingly met her.

1280986.  Thu Apr 12, 2018 2:01 pm Reply with quote

Who's that walking down the street?
Bandy legs, educated feet.
Happy smile, now ain't that sweet.
It's Grandad, Charlie Quick.

1281001.  Thu Apr 12, 2018 5:00 pm Reply with quote

Do we have an interesting or obscure fact for Mistress Quickly?

Perhaps give the original use of quick to "the quick and the dead" saying that many people may use?

Tiny ps...

Nice one ma'am, as in jam...(Tho I presume it was used playfully from the cricket tradition)

Was that rule brought in because the marm pronunciation often morphs into mum and a curtsey and foreign visitors sometimes were under the impression that those actually working for Her Madge called her Mum or Mother as in Mother of the country?

I imagine that could have caused confusion and even a sly ability to offend at times

At least she can be grateful she isnt doesn't have to answer to The Great She Elephant...

1281068.  Fri Apr 13, 2018 6:49 am Reply with quote

My Year 1 teacher was called Ms Quick

1281171.  Fri Apr 13, 2018 11:25 pm Reply with quote

Was she known as Kissme?

DVD Smith
1285527.  Thu May 31, 2018 8:24 am Reply with quote

Q: What invention did Alexander Graham Bell call "the most significant invention in years"?

[Klaxon: Telephone]

A: It was the hydrofoil, after he read about them in an American newspaper article. Bell was so impressed by the hydrofoil that he helped co-design several, including the Hydrodome IV (or HD4) – the fastest boat in the world and the first vessel to travel over 70mph on water.

According to the book The World Water Speed Record: The Fast and the Forgotten, Bell experimented with a few of his own hydrofoils, and then in the 1910s he joined forces with Italian and fellow inventor Enrico Forlanini, who in 1906 had already developed a hydrofoil that could go over 45mph. Together they set out to design a much faster hydrofoil that they could sell to the navies of Canada and the US for use in the First World War.

They weren't initially successful – their first design, the Hydrodome I, successfully reached 50mph but then immediately broke in half. The sequels, Hydrodome II and III, similarly failed. By this point the US Navy, who were intrigued by Bell's designs, withdrew their interest in his prototypes, saying that they weren't much faster than 'conventional' crafts. After Bell's sister Mabel gave them more money to invest, they designed Hydrodome IV, which used two 400hp engines. Finally, in Nova Scotia, under the observation of the British and US Navies, Bell and Forlanini's craft successfully broke the water-speed record and reached 70.86mph.

Unfortunately, neither Navy invested in the project, as by this point it was September 1919 and the First World War was over. Instead their record-breaking craft lay abandoned on the shores of Nova Scotia, never to be used again.

Sources: [1] [2]

DVD Smith
1286491.  Sun Jun 10, 2018 8:25 pm Reply with quote

Q: What record was broken by the fastest kettle in the world?

A: The land-speed record for a steam-powered vehicle.

The record was set by the British Steam Car Inspiration, which reached an average speed of 139.8 mph over two runs in 2009. Its achievement earned it the nickname “the fastest kettle in the world”. [1] [2] The car was 25 feet long, contained 12 separate boilers and according to the website burns at "23 cups of tea per second". [3] The Inspiration broke a record that had stood for over 100 years; the previous record had been set in 1906 by Fred Marriott, who went 121mph in the first vehicle to cover two miles in under a minute. [4] [5]

But this got me thinking - what actually is the fastest kettle in the world? Well, in 2013 Japanese company Tiger released a kettle that could boil a cup of water (140mL) in just 45 seconds, which they claim is the industry’s fastest. [6] However, Braun’s WK500 claims that it can boil 200mL of water in 35 seconds. [7] This still puts it far in the shadow of the Inspiration, which has boiled 805 cups of tea by the time the Braun WK500 has done one. Although you wouldn't really want a cup of tea from the Inspiration, since the water it boils comes out at 400°C. [3]

But all these pale in comparison to the ultimate kettle: the Linac Coherent Light Source (LCLS), an X-ray laser located at the SLAC National Accelerator Laboratory in California. As reported in a paper published in May 2018, by using the LCLS to fire short, intense X-rays at a jet of water, the water can be heated in less than 75 femtoseconds (or 0.000000000000075 seconds). [8] [9] You might be waiting a while for the tea to cool before you can drink it though – the LCLS heats up the water to a spicy 100,000°C. It also might taste a bit weird, since you won’t be drinking liquid any more, you’ll be drinking hot plasma. But at least you didn’t have to wait those 35 seconds, eh Braun? [10]

It's quite hard to grasp just how quickly the LCLS can heat that water up – by my reckoning it's approximately the length of time it takes light to travel the width of a human hair (22 micrometres). In fact, by my calculations, if we assume (perhaps very wrongly) that the LCLS could boil a full cup of water to 100°C within those 75 femtoseconds, then in the 35 seconds it would take the Braun WK500 to boil one cup of water, the LCLS could boil enough water to give approximately 64,815 cups of coffee to every one of the Earth’s 7.2 billion people. (Which I'm pretty sure is a challenge Starbucks have been attempting since 1971.)

1286556.  Mon Jun 11, 2018 10:56 am Reply with quote

Any of these is better than kettles achieve here in the USA, where our wimpy 125v causes them to take two or three minutes at least.

1286721.  Tue Jun 12, 2018 7:36 pm Reply with quote

Jenny wrote:
Any of these is better than kettles achieve here in the USA, where our wimpy 125v causes them to take two or three minutes at least.

Hmm - I may be wrong - but voltage has no effect on how long it takes a kettle to boil surely? It's the current that matters.

Alfred E Neuman
1286727.  Wed Jun 13, 2018 12:53 am Reply with quote

It’s both. P=VI, where P is power, V is voltage and I is current.

Additionally the current will increase for the same resistance if the voltage increases, but American kettles have a different resistance to everyone else in the entire world’s kettles because of their lower voltage.

We have discussed this before, with numbers if I recall.

Edit:- it even has its own thread.

1293401.  Mon Aug 20, 2018 10:49 am Reply with quote

Talking of quicksand, Bear Grylls has a great video of how to escape from quicksand in the Sahara.

He claims that as opposed to attempting to pull your legs up underneath you (as the pressure will be too great), you need to manoeuvre your legs horizontally behind you and aim to get them out that way.

Who knows if this is advice for everyone or just someone as extraordinarily skilled as Bear!

Here's his vid:

The Nat Geo, on the other hand, gave the advice of screaming for help.

Here's their vid:

DVD Smith
1298650.  Fri Oct 12, 2018 8:41 am Reply with quote

Want to see a quick chemical reaction? I present to you the Iodine Clock:

The reaction involves an iodine compound that reacts with starch, hydrogen peroxide and sodium thiosulphate to produce a starch-iodide complex, which gives the dark colour. The reaction is almost instantaneous, but the colour change is delayed because the complex produced reacts with the thiosulphate as soon as its made - until the thiosulphate runs out, at which point the abrupt colour change occurs.

Related to the Iodine Clock is the Briggs-Rauscher reaction, aka The Oscillating Clock, which changes back and forth between light and dark. (Video)

Another one of the fastest chemical reactions known to science happens within our own DNA. It's a reaction that the DNA undergoes when exposed to ultraviolet light, to protect itself and prevent damage to the genes, and it happens in a few quadrillionths of a second.

It was observed for the first time in 2015 using a process called 'femtosecond spectroscopy', where one femtosecond = 0.000000000000001 seconds (aka one quadrillionth of a second).


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