The best of the old and new swings

At another park, upstream from our house, there are two excellent swings which the kids love to play on, one new and one very old.

The old swing has a big diamond head, with the sculpted face of a friendly clown. The whole thing spins round and round, and the chairs swing out wider and wider the faster you go. These swings used to be quite common in Victoria when I was growing up. This one has been recently painted (and possibly serviced), but I’m sure it is at least 30 years old. It is great to lie down with your chest on the swing chair and pretend to be superman, flying through the air.

The new swing is the modern version, in the sense that they are very common, I know at least 6 parks with these swings. There is a big hoop suspended by 4 cables, with netting across the hoop to lie in or sit on. The angled steel beams provide some bounce and spring. I can see why these swings are popular, they are a simple design, overall pretty safe, and a lot of fun to swing on.

Fast slides and good times

Not far from where I live is a fantastic playground. There are swings, cubby houses, roundabouts, and in the center is an enormous tower with two slides down to the ground.

The slides are made from metal, not plastic, so there are no static electic shocks and they are fast. The lower slide is ok for young children who can walk and climb, but it has a slight corner and they can come out sideways if they’re not careful. The upper slide has a steep section, with a lot of acceleration, and for older kids it’s a lot of fun.

There are a few extraordinary parks near my home town. There is a children’s playground in the Melbourne Botanic Gardens with a small stream of water running through it, and kids will splash and stomp through the water and have a lovely time. Bacchus Marsh is a small country town, but across from the train station is a park with a huge wooden castle, with four towers connected by bridges with slides to the ground.

These parks make me happy, they are a tremendous public good for everyone to share. They make life a little bit better for everyone, and I’m grateful to all the people who helped to help make them.

Learning By Heart

When I was younger, I thought that learning things by heart was silly. Memorising facts, figures, names and dates, or a strict old authoritarian school teacher forcing kids to memorise the names of kings – this seemed ridiculous to me. Better to understand the patterns of political history, or the underlying physics and equations of something. You will naturally remember the basic details of a topic as you study it, and that’s enough, any effort to specifically memorise facts is wasted.

When I studied physics later on, this was a common attitude. Many physical phenomena can, in principle, be derived (i.e., mathematically worked out) from a small number of fundamental equations. Some physicists are proud that they cannot (for example) remember the wave equation for light but can derive it from Maxwell’s equations whenever needed (I probably used to be a bit like this). There is a story that the physicist Enrico Fermi once said, about all the newly discovered elementary particles, “If I could remember the names of all these particles, I would have been a botanist…”

I thought I could remember a similar quote by the physicist Richard Feynman, but when I went to look up the quote in the Feynman lectures, it seems that he is actually making fun of such attitudes. Having stated the two fundamental principles of gravity, he says: “A sufficiently talented mathematician could then deduce all the consequences of these two principles. However, since you are not assumed to be sufficiently talented yet, we shall discuss the consequences in more detail …“.

Later in my twenties I worked as a tutor once per week at Fitzroy Library’s homework club, which is a free service for local high school students. Often, students would be there on a particular afternoon because an assignment or test was due the next day. In that case, they didn’t want to understand why the quadratic equation works, or how to derive it, they just wanted to learn and memorise the steps to use as quickly as possible. The test is tomorrow!

Other students would attend every afternoon, so there was more time to explain things and the ideas behind them. I hadn’t done much teaching previously, and so I tried different ways to explain things. What I noticed, though, was that, even for students who were not trying to cram for an exam, it was often better for them to memorise the steps to solve an equation, and then to talk about the general principles behind it. Once an equation is memorised, it would be easier to understand. If you have something memorised, you can hold it all in your head at once, turn it around in your mind, consider it from different angles, as it were. You can try to do this without having memorised it, but it’s harder – you may need to look at the text book every few minutes to remind yourself of the different parts. Once you have something memorised, it is easier to think about it and understand it properly.

Ghost Bird

A few years ago, in the middle of winter, my wife and I moved from our house in inner Melbourne to Cairns in Far North Queensland. Tropical Queensland looked instantly different to southern Australia. There was rainforest in the hills behind the town, and sugar cane growing along the highway. The sun in Cairns was strong and bright, and the landscape seemed to be an intense, rich green instead of the blueish-green, straw yellow and sandy brown colours of down south.

We rented at house at Yorkeys Knob, which is one of the suburbs north of Cairns.(Annual town party: “Festival of the Knob”). It has a lovely beach, which you can’t swim in, both for crocodiles and stinging jellyfish. Across from the beach were a few holiday houses, and a melaleuca scrubland, the size of a football field, which was surrounded by a tall plywood temporary fence which was beginning to fall down. Behind all this were the houses where people lived, a few quiet shops, and the Knob itself, which is a rocky hill with views out to the Coral Sea.

Our house also backed onto the melaleuca and tea tree scrub, which was very pretty, with electric blue Ulyssues butterflies which would fly out into our back garden. However, after we lived there for a few weeks it occurred to me that during the wet season, the scrub might become a wetland or even a swamp, which in the land of crocodiles and dengue fever makes you thoughtful. Certainly, at night the scrub lively and noisy, with croaking frogs and toads and the occasional eerie shriek, noise which sounded like “whee-eer-loooo”, an almost human-like wail in the darkness. At the back of the garden, bordering onto the scrub was the compost bin and two paw paw trees. Every few days, an enormous amethyst python (Australia’s largest snake) would be lying on top of and around the bin, in the sun. It was at least five metres long, with a body as thick as my arm. You could see it lying there from the back door, and since it didn’t surprise me up close I didn’t mind too much. Tropical Queensland was exhilarating, and also a bit intimidating.

We planted a veggie garden in our backgarden, with lots of new plants we couldn’t grow easily down south: okra, snake beans, lemongrass, sweet potato, paw paw, as well as a new fruit which I only heard of for the first time at a local restaurant:

“Would you like rosella jam on the cheesecake?”

“Ah, is the jam made from … rosellas?”

“Oh, yes, certainly.”

“The … bird?”

“No, no! Oh no, the fruit.”

The fruit? I had never heard of it, but after that I had to try and grow some. The plants never really grew, though, so I still don’t know what the fruit looks like uncooked.

My wife and I had recently become interested in birdwatching, though we didn’t really know what we were doing. We had became interested a few months before, through visiting my uncle, who was working as a weather observer for the BOM on Lord Howe Island. He and his partner showed us the tropic birds, shearwaters, boobies, and the famous Lord Howe Island Woodhen. They loaned us their binoculars, and took us to see the weekly show given by Ian Hutton, a resident bird expert. We returned from the holiday, bought some binoculars, and had a great time trying, and sometimes succeeding, to identify the birds in the forests near Melbourne.

When we moved to Cairns a few months later, we were excited to see new birds up in Queensland. We saw sunbirds and bee-eaters in our garden, metallic starlings and red tailed black cockatoos at the local park, a white-bellied sea eagle at Yorkey’s Knob beach. One bird which my wife was keen to see was the Bush Stone Curlew, which she had seen in a photo in Australian Birdlife. She showed me the photo, and then I wanted to see one, too. Curlews have big eyes and gangly legs and a wonderful comic dignity. They used to be common in Victoria but were now extinct there, though they still lived up in Queensland. We looked around Cairns, but we couldn’t find one. In disappointment, one evening I took out my phone looked them up in a Australian Bird Guide app. “Let’s listen to the bird call, that might help.” My phone let out an eerie call, “whee-eer-looooo”. We looked up at each other. That was the same call we heard each night, along with the frogs and toads croaking. We had been surrounded by curlews all this time.

We saw the first curlew a few days later at the Yorkey’s Knob golf course. It moved and bobbed its head, stretching out its neck and looking up at us. It ran with a beautiful long legged gait. I read that they are related to American road runner, and they certainly looked a bit like Wily Coyote’s perpetual foe. Of course, after not seeing them for ages I then saw them everywhere: near the beach, at the park, even in the carkpark at Woolworths supermarket.

My wife and I moved back down south to Melbourne when we had our first child, to be closer to family. When our daughter was one and a half, we went on a holiday back up to Cairns. At the golf course, we saw the Bush Stone Curlews again, and there were tiny chicks with them this time, the first time I ever saw baby curlews. We had a new family, and so did they, adorable chicks, standing near their parents, near the palm trees, gangly and fluffy. The curlews watched us, and we watched them, and then we drove away and left them to their home.

Help To Make The Thing

If you wanted to make a beautiful iron latticework clock for someone dear to you – say for a 50th birthday gift – or colourful glazed ceramics dish, or a wood dining table, it would not be easy to do if you had never done it before. It takes a huge amount of learning, trial and error, safety training, expensive equipment and so on, to make something like iron latticework or ceramics. But it would be fun to do, and even if you were busy, you might be able to spend a whole Saturday on a special occasion gift, especially if you also did it with someone else as well – you and your daughter, and a wonderful artist make a special gift for your partners’s 50th birthday, for example. You could even make it with the person you are giving it to.

Here’s an idea for a business I’ve been thinking about: a service to connect people who want help to make a personal, thoughtful gift, from a skilled and friendly artist who knows how to do it. Call it The business finds local artists and tradespeople who would like to take part, makes sure it can be done safely, and then the customer and the artist work together to make the thing.

Like I said, to safely and skillfully do iron welding by yourself is not easy. Even to know what kind of weld to do in a particular case and what equipment to use is not easy. But I imagine that, under supervision, you could learn to make one kind of iron weld quite well in a short time, and make 20 or 30 of those welds in an afternoon. You could work with the artist on the design, they could do a lot of the other things, mostly using materials and equipment already in their workshop. Or you could apply the glaze for a ceramic pot, or

It would a lot more expensive than simply buying something similar, even from the same artist. They are dedicating extra time, and showing you how to do a part of the process. But it might be a lot of fun, artists who often work alone might doing this five or six days per month. The artists would get extra money, which might them. Meaningful and wonderful gifts would be created.

Anyway, when I am the billionaire founder of this business, you’ll be able to tell people you heard about it before I was famous.

What A Country

When our first child was born, a very nice nurse came to visit us every few weeks or so, from when we first got home to when our daughter was two months old. The nurse was friendly, helpful, did a health check, gave good advice, and was very much appreciated.

After two months, the nurse stopped visiting us at home, but we visited her at her office every few months. It was a great service, but we weren’t special – every new baby in Australia gets this, as far as I know, tell, and it was absolutely free.

I remember thinking to myself: “what a country” (which is a quote, more or less, from the movie The Castle). I remember thinking how wonderful it was, at this crazy time in your life when you have a new baby, and you don’t know what to do, and you’re feel overwhelmed at times, that every single person gets a friendly, knowledgable person come and help them for free. It makes you feel like the country cares about your baby.

What a difference it was that it was free, rather than having some co-payment. I would have been happy to make a co-payment, but I realised how different completely free feels to a co-payment. By this time, I had been paying taxes for quite a few years, and obviously I had been getting many benefits that whole time (roads, firefighters, the ABC, a country which is well defended etc.), but this was a benefit which felt very personal. Everyone in the country, including me, is paying taxes to give newborn babies a little help. Then it occurred to the country probably also paid for someone to help my parents when I was a baby. That’s a thought. And a few years later, I went to a hospital emergency room, and at the end they wished me a good night and I walked out, again completely free.

What a country.

Many people advocate co-payments for government services, and in general I agree. Making a service cost something – even a little, even if it’s less than the service costs to provide – causes people to check if they really need it, and to value it more. “People don’t value what they don’t pay for” is the saying. It can help ensure that resources aren’t wasted. For many cases, that is a good principle. But I think that sometimes, completely free is better.

Discovery Of Helium Under the Earth

Another story from the discovery of helium is when it was discovered on Earth in large quantities. As I wrote in part 1, helium is so light that it will escape into space over time, and there is almost no helium in ordinary air less than (0.0006%). When helium was first discovered, it was trapped in tiny amounts in rock, where it had been created by nuclear reactions (for example, in uranium ore). These nuclear reactions tend to be slow, so the amount of helium obtained was very small. In 1900, it seemed that helium was so rare that it was unlikely to be useful for anything much.

Well that did change as you probably know and it is a nice story.

In 1905, a large natural gas well was drilled in Kansas, USA, which had huge amounts of gas coming out, a “howling gasser” as they said at the time. When it first discovered, it was estimated to be releasing 250,000 litres of gas per day (9 million cubic feet). (Methane has huge green house gas warming potential, so that is regrettable, but at the time of course they didn’t know about such things). The well had still not been capped – it was going to take some time for the equipment to arrive. So the townsfolk decided to have a huge celebration to celebrate their good fortune, and the impending wealth and industry that was likely to come to their town. The celebration would finish with lighting the escaping gas, which would burn non-stop until the well was capped. (I don’t actually know how they planned to extinguish such huge flame to cap the well, but I assume there is a way to do it).

The celebration had games, and music, and speeches. You can imagine a town party in rural America at the start of the 20th century. Colourful bunting flags. Distinguished old men in three piece suits with moustaches and muttonchops. Ladies in frilly dresses. The band with a tuba going omm-pah-pah.

At the end of the night, a burning bale of hay was pushed towards the gusher of escaping gas (with a long stick, one would hope). The band would have gone silent. Everyone is standing around (again, not too close), watching expectantly. The burning hay approached the hole and … Suddenly the flames went out. People say, “What? Huh.” The bale is retrieved, re-lighted, pushed back towards the hole. Again it goes out. They try a third time, and again it goes out. The crowd sighs. What is going on?

The celebration ends in an anti-climax. People go home wondering what happened, and what indeed is the gas coming out of the ground. Some people say it is a well of “hot air”, not natural gas. Sometime later, people come from the University of Kansas, and take a sample in a steel barrel. Analysis is done, and they find that gas does contain 15% methane (natural gas), but also 80% inert gases, most of which was nitrogen – too great a concentration for the bale of hay to burn. The gas also contained what they thought was an amazing 1.5% helium. Given the amount of gas coming out of that well, if even one percent of that was helium, that was millions of time more helium than had ever been discovered before. Helium was no longer rare, and was now able to be used in balloons, to make your voice funny, fly huge zeppelins, and also make MRI machines. Even today, all helium you use is mined from the ground in natural gas wells. Helium is even regulated by the US government as a “strategic reserve”. So the disapointed Kansan partygoers walking home that night actually had something to celebrate, they just didn’t know it.


Discovery of Helium in Natural Gas at the University of Kansas, American Chemical Society, 2000

Helium was discovered on the Sun before the Earth

As part of some barely work related research I have been doing, I read some new sources on the discovery of helium. I have always loved the fact that helium was discovered on the Sun before it was discovered on the Earth. It seems like an amazing thing – an entirely new element was discovered in the Sun, which no one had ever knew of before, and then only 13 years later it was discovered on the Earth. But no has ever been to the Sun to do testing, so how did they even know it was the same element they had previously found in the Sun?

Helium was discovered in the sun by taking sunlight, splitting it up into different colours, (such as in a glass prism, but they actually used a diffraction grating) and noticing that certain colours were much brighter than any other colours. Every kind of gas will emit (or absorb) very particular colours of light. At the time, they didn’t know why elements did this (quantum mechanics), but they did know that it was a unique, unchanging signature for each element. All hydrogen, for example, emits the same particular shade of red, light blue, dark blue, and purple, regardless of whether it is in France or India or Peru:

Because these particular shades are so specific (and the wavelength of each can be measured so precisely), that means that by the 1860s it was possible to determine that the Sun was mostly made of the same elements that were found on Earth. Which is already a pretty amazing discovery. The Sun could have been made of anything – completely different to anything on Earth. There was not much understanding of how the Sun worked, beyond a thousand year old notion that was somehow like fire. But nothing on Earth burned as long or as hot as the Sun (nuclear reactions weren’t known of yet.)

So in 1868, during a solar eclipse, Jules Janssen and Norman Lockyer (who later founded the journal Nature) each measured the spectrum of light from the sun, and found that it contained sets of colours (“spectral lines”) from many elements known on Earth, such as hydrogen, and some that they could not identify. The College of Chemistry in London tried to reproduce the lines from samples they had, but could not, suggesting that it was an element unknown at the time.

In 1881, Luigi Palmieri found similar colours in gases from an eruption on Mt Vesuvius, and in 1895 they were also seen in uranium ore by Sir William Ramsey, and not long after people realised that these were the same colours that had been seen in the Sun, and that it was the same element. The confidence in reasoning, the cleverness, to say that this thing we only previously found in the Sun, we have now found on Earth, I still find amazing. It is cool in the same way as anti-matter, or cosmic background radiation, which were predicted theoretically before they were discovered.

Incidentally, the reason helium had never been found before on Earth is that it weighs so little that, on its own, it will gradually drift out into space. Even in the cold upper atmosphere, the average kinetic energy of helium atoms is above the escape velocity. This is also true for hydrogen, but hydrogen is produced in many chemical reactions, so it was found much earlier. Helium is chemically unreactive, and all original surface helium left Earth billions of year ago, so. To be discovered, helium had to be found that had been trapped inside the Earth (like on Mt Vesuvius), and produced in a nuclear reaction inside rock (like the uranium ore). All the helium you have ever used in your life, all the helium balloons, every time you’ve even made your voice go high and funny, that helium was all mined from the Earth, as I write about more in part 2.