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20 September 2018 – Into The Underworld

Into The Underworld is back on! An exhibition of laser scanned images of Auckland's lava caves held in Silo 6 in Wynyard Quarter, Into the Underworld (www.intotheunderworld.nz) gives a unique view of Auckland's volcanic heritage, and shows just how close our lava caves are to suburbia.

The images themselves are stunning, with some up to five metres tall, and others up to seven metres wide. The exhibition is open daily noon to 9pm and runs until Monday 1 October 2018.

6 September 2018 – Acetylene

When using acetylene it's really important to know what you can and cannot do. Acetylene is a flammable gas – indeed, known for its particularly hot flame – and like many flammable gases it's dangerously explosive at the right combination with air (or with pure oxygen). That last bit is really important... and basic science. It means acetylene has to be stored and used carefully.

Acetylene also has the interesting property that if you pressurise it to about 2 atm it can spontaneously explode, decomposing into other stuff like hydrogen and carbon. To avoid that happening, acetylene cylinders contain acetone, a liquid in which the acetylene dissolves. Copper catalyses this reaction, so copper and brass fittings should not be used. The cylinders need to be used vertically so the acetone does not come out.

This is pretty straight forward stuff, but on Monday 3 September two people missed applying the simple science and a father of three children died. The NZ Herald detailed (warning, graphics details) how it happened: a guy put acetylene and oxygen together in an LPG cylinder and his friend didn't stop him from going back to it.

In July 2017 I talked about how a lack of basic science knowledge caused the deaths of 15 people from a cornflour fireball. As I said at the time, science enriches lives, broadens horizons, and can save lives.

11 July 2018 – Wild Boars Coach

With monsoon rain from May to October it's a fair question to ask why the coach Ekapol Chantawong took the team into the cave at that time of year. We should consider several points to put this question in perspective.

Two signs outside the cave says it's closed July to November due to flooding (calling July to Nov the "flooding season"), which doesn't actually give any reason for the coach to think it wasn't safe on 23 June. There are guided tours through the first kilometre from November to June, which again gives no reason to think it is unsafe in June.

A local points out that the cave is "a magnet for teen adventurers". A trip to the cave was thus ideal for a team-building experience. It wasn't the team's first trip to the cave, so it clearly served the purpose the previous time, two years ago. (I don't know what time of year the previous visit was.)

Yes, it turned out to be the wrong decision, but that's really only clear in hindsight. Yes, he should have told the senior coach where they were going.

However, I think it's more important to look at what Ekapol Chantawong contributed to the survival of the team. Not only were the boys alive when found, they were alert and mobile, and calm.* From his own tragic history, and years of spiritual training, it seems that he was the perfect man for the job. He lived for the team is his life, and it could be argued they lived for him in the cave.

11 July 2018 – Wild Boars all safely out

In an incredible rescue effort involving thousands of people the whole 12 members of the Thai football team and their coach are safely out of the cave, along with all the rescuers. The selflessness shown by the more than 130 divers, the other rescuers, and the up to ten thousand volunteers working behind the scenes is truely inspiring. From an initial situation that seemed like a Schrödinger's cat situation, this is an extraordinarily good result.

The sad death of former Thai navy diver Saman Kunan was a sobering reminder how dangerous the work was, but the mission to evacuate the team was brilliantly planned and prepared for, and executed flawlessly over the three days it took to swim, walk, and carry the Wild Boars out.

Also sad is the death of the father of Richard Harris, the cave-diving Australian anaesthetist, on Tuesday a short time after the rescue was completed.

Those interested in learning more about caves might like to contact a local caving club, such as Auckland Speleo Group.

9 May 2018 – Term 2

My schedule is pretty full now, with just a few slots available. I may not be able to find a time that will suit, but you're welcome to ask.

Enquiries for one-off holiday sessions for the end of term 2 are welcome.

11 April 2018 – Power Cuts (updated)

The storm that raged last night has taken its toll. The Homeschool Science Fair that would have been this morning was cancelled postponed until Wed 2 May due to no electricity at the Fickling Centre, which also meant no access.

What's more, according to the Vector power cut location cellphone app, up to 10 11 12 of my present students and as many as 14 16 17 24 27 of my former students are (or have been) without power. They are due to have it restored between midday today (Wednesday) and 6pm tomorrow midday Friday 10pm Saturday. I hope they all stay warm and dry.

I found bits of corrugated plastic scattered around five properties this morning. Close examination shows they were part of a roof, but I haven't found where the roof was or why it (apparently) exploded.

23 January 2018 – Back To School

At least one of the schools my students attend starts today. Now would be a good time to get in touch if you're pondering tutoring this year.

Enquiries for holiday sessions for the end of term 1 are welcome.

21 January 2018 – Insertion Into Orbit

NZ founded company Rocket Lab has successfully launched (video) its Electron rocket Still Testing into orbit, and successfully inserted three satellites into an 83° orbit, taking 8 minutes 31 seconds before satellite release. This was only the Electron's second test flight, and the orbit attained is a little more difficult than an equatorial orbit because of the extra speed required.

The test had been scheduled for yesterday (20 Jan) but had to be postponed after two boats strayed into the exclusion area down range of the launch site. Update – the day was not a complete write-off; it generated a classic Rocket Lab quote.

A third test flight is planned, launching into a sun-synchronous orbit (see polar orbit) at an altitude between 300 km and 500 km. After that, Rocket Lab plans to launch up to 50 rockets each year, although they are licensed to launch up to 120 per year.

2 December 2017 – Into The Under World

For the last couple of years I've been helping do high resolution 3D laser scanning of Auckland's lava caves. To show off the scanning work, next Friday (8 December) sees the opening of an exhibition: Into The Under World. Apart from the opening night it's a free exhibition, held at Silo 6 in the Wynyard Quarter.

The images are spectacular and well worth seeing at full size, back-illuminated, but be warned the exhibition has a very short run, closing on 24 December.


8 November 2017 – Bright Sparks

Congratulations to intermediate school student Brian Kitchen for his incredible Bright Sparks 2017 entry Xtionberry Pi, which he has been working on for the last two years. Brian is winner of 1st place in the Junior Engineering category and Overall Male Winner.

His project video only shows the first half of his project, and doesn't show the amazing work he's done figuring out how to create apps for MacOS, Windows, Android, iOS and websites, that enable people to move around at will inside his scanned caves.

Keeping cool under fire (literally, as it turned out), he was demonstrating his scanner to Seven Sharp reporter Tim Wilson on the morning of the prize giving (yesterday) when a capacitor on his scanner's homemade power supply burst into flame. But Brian implemented his backup plans and outside the prize giving that afternoon he was showing off his scanning abilities anyway. His persistence, motivation, and ability to stay calm are really quite incredible.

Update: Brian was also interviewed on RadioLIVE on 3 December.

29 October 2017 – Extrasolar visitor

This month the solar system had its first known interstellar visitor – a body from outside the solar system, travelling faster than the Sun's escape velocity, so it's not going to end up in orbit. This hasn't been seen before, so it's presently designated as an asteroid, A/2017 U1 (although it was originally called C/2017 U1 because it was thought to be a comet). Update: Now called ‘Oumuamua, it appears to be unusually elongated – possibly more so than any other* natural object – having approximate dimensions of 30 to 40 m diameter and 180 to 400 m long. *Assumed.

It was first spotted on 19 October 2017 when it was "just" 30 million kilometres from Earth (0.2 AU; Earth's orbit is 1 AU from the Sun), and it has been calculated that it got within 24 million km (0.16 AU) from Earth a few days earlier on 14 October. At its closest approach to the Sun it was closer to the Sun than Mercury is, at about 0.25 AU (Mercury is at an average of 0.39 AU).

An eccentricity of 0 is perfectly circular, while 1 is a parabola (in a sense an infinity long ellipse). A/2017 U1 has an eccentricity of almost 1.2 – firmly hyperbolic, meaning it's not gravitationally bound to the Sun, having come from outside the system and now heading out of the system again. The direction it came from was the constellation Lyra (4½° away from Vega), which is the direction the whole solar system is moving in. More info here.

3 September 2017 – Science Fair

The NIWA Auckland Science & Technology Fair has been and gone for another year, with a huge range of really interesting topics covered. Students in year 8 (intermediate school students moving to secondary school nex year), don't forget that you can enter next year even if your secondary school doesn't participate. Just get in touch through the Sci Fair website (or with me) – the sooner the better.

14 July 2017 – Particulate fireballs

To finish off term 2 I introduced some young scientists to oobleck – a colloquial name for the non-Newtonian fluid made from cornflour in water. It acts like a liquid when treated gently, but as a solid when hit hard (as this video shows very nicely with a golf ball). It's fascinating stuff to play with (even for adults), and was voted the best lesson of the term.

We also had a look at what happens when a cloud of cornflour in air is ignited: a fireball. Increasing the surface area of a substance increases its reaction rate. Cornflour is flammable and is a fine powder, so has a very high surface area and will burn rapidly if given a chance. As a cloud of dust in the air, it's mixed with the oxygen it needs to combust, so at the right concentration all it needs to set it off is a source of ignition.

This is really important to know, because flour and cornflour explosions do happen because of ignorance. Two years ago a cornflour fireball at a water park party in Taiwan caused the death of 15 people, and almost 500 people were injured. Four months later 44 victims were still in hospital. Quite apart from cornflour being really bad to breathe, smoking was allowed at the event – a source of ignition. At the end of this news article a Taiwan government minister is reported saying "if there had been someone with a basic understanding of science at the scene, the tragedy could have been prevented."

Science enriches lives, broadens horizons, and can save lives.

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