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Australian chemistry vacation

28 November 2011 - Leisure mode

You cannot blame a chemist for taking an interest in chemistry even when on vacation. So here is what your bloggist has to report on his recent three week stay in the Sydney - Melbourne - Hamilton triangle.
Sydney's two icons are the Sydney Harbour Bridge - 50,000 tonnes of steel - and Sydney Opera House - 26,000 tonnes of concrete. This blog admired the bridge but was having doubts on the opera house. Should not design follow function? The roof starts at eye level so it is easy to inspect the white ceramic tiles. The interior when entering the building is not decorated at all - just plain concrete. The tiles must have been a desperate solution by desperate engineers. As a building concept this homage to concrete certainly never caught on.

Australia is of course all about mining. The newspapers all agree that the country will get very rich from this industry in the coming years and the only thing that needs to be settled is how to tax and how to divide the earnings. Even selling uranium to India is no longer an issue. A new technology for gas exploration making headlines is fracking.
Evidence of past industries can be found in the blue mountains. Katoomba is now a focal point for hiking but remnants of coal mining can still be found. Even further away Hill end was a booming gold town in the 1870's and today an open-air museum. The local museum has a large display on the chemistry involved ranging from gold assaying to manufacturing explosives (nitric acid for on-site gelignite production).
The "Bald hill mine" never produced an ounce of gold. In 1872 an 80 meter shaft was dug to expose three layers of quartz. These layers are oriented perpendicular to the shaft and are hundreds of meters wide but only centimeters in thickness. Gold would then be present in the shape of flakes but gold never materialized. After this disappointment someone suggested that further down the mountain surely there had to be diamonds to be found. After laboring for another year excavating an airshaft and another 200 meters of mine tunnel the stage was set for disappointment number two.

The city of Melbourne is another gold-rush town but whereas the population of Hill End over the years dwindled to just 166, Melbourne now hosts over 4 million people. The city does not do iconic buildings like Sydney but makes up for it with a post-modern city center and an even post-post modern Yarra river southbank district. The city has electric trams and a public bike scheme so the environmental awards should be flooding in.
The nearest icon would probably be the Twelve Apostles site on the Great Ocean Road which are big blocks of rock in the surf pretending to guard the coast. In terms of material science the choice for limestone is unfortunate because the waves tend to eat it away but on the other hand as one apostle collapses after the other, new apostles are in the making.

The lake Taupo region in New Zealand is a volcanic hotspot. The NNNS geological museum (founded 1975) now boasts pieces of pumice and granite picked up during the Tongariri Alpine Crossing.
Water is the color blue? Boring! The emerald lakes on top of Mount Tongariro appear green due to leached minerals from thermal activity. Further downstream the water passing the Huka falls (from lake Taupo into the Waikato river) too has an unusual color, this time attributed to dissolved air. The Inferno Crater in the Waimangu Volcanic Rift Valley is part of a large hydrothermal system and the color of the water depends on the water level which changes periodically. The color is a bright blue when the water level is high due to a combination of suspended silica particles and turbulence. The iodine pool on the same site is only so-called because the mineral deposits have an ugly brown color.
The masters of chemistry in the Taupo area must be the glowworms (Arachnocampa luminosa) lurking in the Waitomo Caves. Suspended from the ceiling they attract insects looking for a way out of the cave by luciferine -based biolumiscence and trap them with a silk thread. The wikipedia article mentions that the illusion created is that of a starry sky at night. This blog disagrees: the ceiling looks more like a blue sky behind a forest canopy. In some way the distribution of the glowworms on the ceiling has relevance. It makes good sense that photography is not allowed inside the cave so if you want to find out for yourself you have to go there.