Category Archives: Chemistry

Carbon monoxide alert: take care when burning fuel

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Powerhouse Museum collection, object 2000/113/7. Gift of Cooranbong Colliery - Powercoal Pty Ltd.

Powerhouse Museum collection, object 2000/113/7. Gift of Cooranbong Colliery – Powercoal Pty Ltd.

Coal miners are very aware of the risks posed by fuels. Whenever they go underground they carry self-rescuers like this one, which turns toxic carbon monoxide into harmless carbon dioxide. News that a Sydney family was rushed to hospital recently suffering from carbon monoxide poisoning demonstrates that the rest of us should be just as aware of the dangers.

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Philosophical bubbles, alcohol content and the awesome significance of glass

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PowerhouseMuseum Collection, object H5266. Gift of R C Dixon, 1954.

Powerhouse Museum Collection, object H5266. Gift of R C Dixon, 1954.

How can you prove the alcohol content of your whisky, brandy or gin? This question has long been of interest to distillers, excise collectors, publicans and serious drinkers. This intriguing and inventive box of calibrated glass bubbles provides one answer. It is also a singular example of the significance of glass as a material of science, utility and beauty.

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The Mr Taylor recovered glass plate negative

Doing jigsaws at work, recapturing an 1880s image

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The Mr Taylor recovered glass plate negative

The recaptured image from an all but destroyed glass plate negative

Most people don’t have the patience to attempt what our recent intern, Amir Mogadam from the Universtiy of Newcastle has just finished – probably one of the most challenging jigsaws you’re ever likely to see. But conservators are a patient if somewhat quirky mob. Amir worked with conservator Rebecca Main on a storage project to condition report, treat and rehouse a collection of large glass plate negatives (515 x 415mm) which were produced around 1870-1880 at the Freeman Brothers Studio, Sydney.
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History Week 2012 Threads – Sevres plate depicting textile dyeing process

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Collection: Powerhouse Museum. Object number 93/277/1.

Here’s a rare treat for History Week: a richly illustrated and gilded porcelain plate that links the threads we wear with history, science, and the processes used in the textile and ceramic industries. The plate was made in the French town of Sevres in 1830 and depicts textile dyeing in another French town, Jouy-en-Josas. The use of colour in these industries depended on both craft knowledge and scientific understanding, and it was achieved through cooperation between factory workers and chemists.

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How to make a nib – a story of gold rainbows and diamonds for Valentine’s Day

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Powerhouse Museum Collection.

I struck gold in the basement last week: 14 carat gold in the form of this delightful didactic display showing stages in making a fountain pen nib.


Powerhouse Museum Collection.

Note the shape of the ‘breather hole’, which exposes ink to the air and helps it move smoothly towards the writing tip: a tiny heart. The perfect nib for writing a Valentine’s Day card!

Gold has been used to make jewellery and keepsakes since ancient times. Pure gold is too soft to use for nibs, or indeed for jewellery, so alloys are used instead. To make 14 carat yellow gold, the pure metal is alloyed with copper and silver; 58.3% of the mixture is gold, and the rest consists of equal amounts of copper and silver.

A nib with a gold point would wear quickly, so a tiny quantity of a fourth metal is fused onto the writing tip. This is iridium, a very rare, very dense element. Like gold, it is highly resistant to corrosion, and an iridium-tipped gold nib can last a lifetime and write millions of words.

Iridium derives its name from the Greek goddess Iris, whose symbol was a rainbow. The chemist who discovered it, Smithson Tennant, named it for the ‘striking variety of colours which it gives, while dissolving in marine acid’ (hydrochloric acid). Just the element for penning a Valentine’s Day card with hope in one’s heart!

Tennant also discovered the true nature of diamond, another gift we associate with romantic love. He did this in 1796 by rather unromantically heating diamonds with potassium nitrate in a gold vessel and deducing that diamond is merely a crystallised form of ‘charcoal’, the element we now call carbon.


Powerhouse Museum Collection.

The gold nib display was donated to the museum in 1924 by the Wahl Company of Chicago, which later made pens with the brand name Eversharp. Reaching behind it on the basement shelf, I found this slightly battered card listing the steps in making a nib. As well as adding value to the object, this list has a certain inherent charm. It links us to the person who wrote it by hand, perhaps using a gold nib with a tiny heart delivering ink to its rainbow tip.

Flash of insight led to brilliant Australian invention

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Atomic absorption spectrophotometer. Powerhouse Museum Collection.

Dr Alan Walsh had an ‘aha’ moment while gardening in 1954. Straight away, he phoned a friend and said: We’ve been measuring the wrong bloody thing! A CSIRO chemist, he wasn’t referring to delphiniums (blue) or geraniums (red). He was thinking about atoms that emit characteristic colours when heated in a flame – elements such as strontium (red) and selenium (blue).

At that time, the concentration of certain atoms in a sample was determined by measuring the amount of light the sample EMITS when heated in a flame. He realised it would be better to measure how much light of a particular colour (wavelength) the sample ABSORBS. He thought his ‘atomic absorption’ method would be more accurate than the emission method.

Now Walsh had been thinking about this problem off and on for years. In his ‘aha’ moment he realised it was possible to get around the major stumbling block: the need to filter out the emitted light so it didn’t swamp the measuring device.

Walsh soon set up an experiment to test his ideas. It worked brilliantly. With the help of other scientists and technicians, he designed a new type of lamp containing the element to be measured. His technique did prove to be more accurate than the old method – and it was more sensitive, and useful for many more elements. His work led to the creation of a local industry making atomic absorption spectrophotometers (AAS). It also led to scientific and practical advances in many fields as CSIRO scientists developed new techniques and labs around the world purchased the instruments.

One of these instruments was offered to the Museum a few years ago by Tim and Kylie Bennett from Alstonville in northern NSW. They were planning to upgrade to a new AAS for their analytical service lab, and the donation of their old one was very welcome. They told us its original owner was the University of New England, where it had been used for studying domestic ruminant physiology.

Now that more information is available online, it appears highly likely that the ruminants studied were sheep and the instrument was used to show (among other things) that they need copper and zinc in their diet to grow good quality wool. A nice connection to our wool and textile collections!

More information is also available about the work of the Bennetts’ company, Soiltec. As its name suggests, it was involved in analysing agricultural soils, but it also analysed plant material. This work was largely aimed at helping farmers grow crops without adding unnecessary quantities of fertiliser to the soil. A nice connection to our sustainability theme!

Making connections is a vital role for museums. These include connections between objects and ideas; connections between disparate objects; connections between objects and images; and, most importantly, connections between objects, ideas and people. I hope my chemistry-themed blog posts for the International Year of Chemistry have made some interesting connections for you.

Hits from the bong

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Collection: Powerhouse Museum

People are usually quite shocked when I tell them we have this bong in the Museum collection. Perhaps because the type of bong shown above is hand-made? Common? Looks a little like rubbish?

I’m not sure why it is so shocking, museums all over the world have drug paraphernalia in their collections. The Powerhouse itself has a nice collection of opium pipes, ceramic water pipes, and syringes.

This particular bong was collected by the Health and Medicine Curator in 1996, and she states

The smoking of marijuana is becoming an increasingly common recreational pursuit in Australia. Even though marijuana remains an illicit drug, many kinds of manufactured bongs are freely available in specialty shops. However, amongst young people with limited incomes, the home-made, disposable bong is very popular. Often referred to as ‘Orchy bongs’, after a brand of orange juice, they are made from a plastic sport drink or juice bottle fitted with a piece of garden hose. The rise in popularity of this style of marijuana smoking explains the mysterious rash of chopped hoses in the front gardens of Australian suburbia in recent years.

The advantages of this kind of bong are; Firstly, they are cheap – manufactured bongs are expensive and often breakable, whereas the only outlay for the user(s) of an Orchy bong is the metal cone. Secondly, they are disposable, so that when they become dirty and smelly they do not have to be cleaned but can simply be thrown away. Disposable bongs are a common sight in gutters, stormwater drains, parks, beaches and other places where rubbish accumulates.

This particular example was found in a street gutter in Ultimo, an inner-city area of Sydney. It is made from a … drink bottle and is decorated with graffiti-style insults, probably written with a green … paint pen. For the Powerhouse Museum collection, it is a significant example of the ephemera of life in the 1990s.

I thought I would write this blog post as a reminder that not all museum objects are shiny, pretty, or expensive. Some come straight from the gutter, yet are intrinsically valuable in the power they possess to tell a story.

Building a better rechargeable battery

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This blog was written by intern Brett Szmajda, who is researching the vital topic of energy storage.

I’m sure that many of you have heard of the Toyota Prius, the Tesla Roadster or the Chevy Volt. Hybrid and fully electric cars are making a big splash at the moment, promising quieter travel with fewer tailpipe emissions. In time, and with improvements in battery technology, it’s conceivable that electric cars might replace gasoline-powered cars.

Would you be surprised if I told you that the battle between electric and gasoline-powered vehicles is over 100 years old?


Powerhouse Museum Collection.

In the early 20th century, gasoline-powered cars and electric cars coexisted. There were even steam cars. Gasoline cars had greater range and could be ‘recharged’ instantly with a jerry-can of petrol, picked up from the general store. But they were loud, smelly, and difficult – even dangerous – to start: the only way to start them was by manually winding a heavy crank shaft, and if the car backfired the crank shaft could break your arm! By comparison, electric cars offered quiet operation and easier start up, with roughly the same limitations that they have today: once you were out of power, you faced a long wait while the car batteries recharged. The pros and cons on each side were roughly balanced, and because of this an interesting innovation race took off.

One big name, fighting for the electric car, was Thomas Edison. Electric cars, back then, ran off rechargeable lead-acid batteries that were essentially the great-great grandfather of the auxiliary lead-acid batteries in today’s cars. Edison thought he could do better, and that brings me to today’s object.

Pictured above is a B-2 nickel-iron (or ‘Edison’) battery. The sectioning of the battery gives us a nice look at its internal workings and lets us see how it compares with later ‘dry cell’ batteries like the Columbia ignitor. B-2 is simply a model number used by Edison to distinguish batteries used for different purposes, much like today’s batteries are AA, AAA, C, D, and so on. This particular model was not used for electric cars (that responsibility fell to its big brother, the A cell); instead, the B-2 was typically reserved ‘for ignition, and other light work’. Other uses for Edison batteries included telegraphy, and running lamps and signals in mines, trains, and ships. Large nickel-iron batteries were even deployed in submarines in World War I.

One of its most desirable features was that the Edison battery was nigh-on indestructable; workers at Edison’s factory performed wear testing by repeatedly throwing the battery out a third-floor window. It was also rugged electrically; the cells could withstand being left uncharged for decades, before working just-like-new after a fresh charge and electrolyte top-up. Detroit Electric Car

Edison batteries were used to run another item in the Powerhouse collection: the Detroit Electric car (see right). In fact, Edison himself owned one. The Detroit electric boasted a range of about 130 km (if driven conservatively) and a top speed of around 50 km/h. There was a surge of popularity for such cars again during World War I, when the price of petrol rose sharply. A public charging point was even installed at Palmer Street in the Sydney CBD, allowing you to recharge your electric vehicle for a modest fee. (I find this revelation quite funny, as a century later, we’re having debates about ‘range anxiety’ on electric cars and how to recharge your electric car while on vacation).

So whatever happened to the nickel-iron battery? Why do we have a lead-acid battery under the hood of our car nowadays? It was probably a combination of things. The electric starter motor was invented in 1911, eliminating one of the biggest drawbacks of petrol cars. Part of it might be the limitations of the Edison battery: it cost more to manufacture than a lead-acid battery; it was greatly inefficient at low temperatures, rendering it almost useless in winter; and it performed poorly in situations where a high discharge or high recharge rate was required. I’d also speculate that the market also played a role: petrol car manufacturers likely had business agreements with certain battery companies. Because of its wide range of other uses, the Edison battery was produced for over half a century, with production only stopping after Edison Storage Battery Co. was acquired by Exide Batteries.

So if you happen to be digging around in the grandparents’ tool shed and find an old Edison battery, you can tell your friends that you’ve found a part of one of the first electric cars. Hell, if you feel like fun, replace the electrolyte, and try (carefully!) giving it a charge. It’ll probably still work.

History week: science delivers our daily bread

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Powerhouse Museum Collection.

It’s International Year of Chemistry and History Week, which this year has food as its theme: a perfect time to meet Frederick Bickel Guthrie, the chemist on this medal. Guthrie worked with a better-known Australian scientist, William Farrer, to develop strains of wheat that were resistant to both drought and rust, a fungus that damages grain and reduces yields. Rust is causing problems in the wheat industry again today.


Powerhouse Museum Collection.

This sample of rusted wheat was collected in 1890. Farrer’s Federation wheat variety helped the wheat industry revive in the following decade. This is why he featured on our first $2 banknote alongside drawings of wheat stalks.


Powerhouse Museum Collection.

Farrer systematically crossed wheat varieties and selected for desirable qualities, but he only grew small plots of each type. In a world-leading research program, Guthrie made a miniature roller mill to produce flour from the small quantities of grain that Farrer produced. He carefully analysed the flour’s gluten, bran and pollard content, noted its strength and colour, baked tiny loaves of bread from it, and advised Farrer which varieties were most nutritious and gave the best quality bread.


Powerhouse Museum Collection.

Here are the wheat stalks that artist Gordon Andrews used as models for his banknote drawing. They are in very good condition, stored in our archives along with his sketches. The fact that wheat can be stored for long periods helps make it a valuable commodity and a staple crop in many countries.


Powerhouse Museum Collection.

Wheat also featured from 1938 to 1966 on our pre-decimal currency, on the threepence coin. Like the $2 note, it is a testament to the value of this crop to our daily lives and national economy.


Powerhouse Museum Collection.

Guthrie popped up again when I decided to research the use of instruments like this chondrometer, made by Henry Simon in England. Despite the fancy name, it’s simply a device for measuring a small volume of grain (in the conical vessel) and weighing it by hanging the little bucket from the steelyard, whose base screws into a hole in the top surface of the box: a neat, portable unit for checking the density of a sample taken from a wheat crop. Density is a guide to wheat quality and determines the space required to store and transport the crop.

I was surprised to discover that this instrument is so crucial to wheat economics that in 1918 the NSW government set up a ‘chondrometer investigation committee’. I wondered if Guthrie was a member of this body – and one contemporary news item confirmed that he was. The committee considered the available chondrometers and approved a model that combined various features of those on the market.


Powerhouse Museum Collection. Donated by Tooth and Company Ltd under the Australian Government's Tax Incentives for the Arts Scheme, 1986.

Back in the basement, I discovered a NSW standard chondrometer, with the name of Sydney maker AL Franklin faintly visible on the steelyard. This instrument complies with the main recommendation of the committee: to cover a smaller range of densities, from 32 to 75 pounds per bushel (compared to 13 to 70 on the Simon chondrometer and 0 to 80 on others) and thus give more precise measurements.


Powerhouse Museum Collection.

Our collection includes objects that represent every facet of the wheat industry and the everyday use of wheat products, from ploughs to harvesters, from a wheat wagon to grinding mills, from flour bags to toasters. This 1880s model shows all the processes that take place in an automated flour mill. I was intrigued by the final step: the ‘silk dressing machine’ above the bags. It turns out that silk is still the best material for dressing (sifting) flour. One more search was in order: do we happen to have any dressing silk in our collection? The answer is yes: two swatch books with silk of varying mesh sizes! The moire effect makes them a bit tricky to photograph, so here is a small sample of one of them.


Powerhouse Museum Collection. Gift of David Sheedy, 1991

Science Underground: limelight burner

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Powerhouse Museum Collection. Gift of Mr A W B Burns, 1972.

Chemists have not seen much of their discourse become part of popular culture, but the symbol for water is a notable exception. In advertising speak, H2O has a high recognition factor. It has been adopted and adapted for a plethora of cool brand names, a few geeky jokes and a successful Australian TV show and spin-off movie.

The symbol is a very neat way of summarising what we know about the composition of pure water. In each and every molecule of this ubiquitous substance, two hydrogen atoms are bound to one oxygen atom. Amazing stuff: we know from experiment that two invisible gases react to give this vital liquid; again from experiment, we know that two volumes of hydrogen react with one of oxygen; and we know, based on a wealth of careful experimentation and robustly debated theory, that this ratio is embodied in tiny invisible molecules made up of even smaller atoms.

What does this have to do with today’s Powerhouse Collection object, a limelight burner? Its two inlet pipes are designed to funnel hydrogen and oxygen gases towards the pointy end, where their reaction generates water and heat. The flame is directed towards the vertical spike, which is designed to hold a ball of quicklime (calcium oxide). Water reacts with quicklime, producing even more heat and a very bright light.

The use of limelight burners as theatre spotlights led to our saying ‘to be in the limelight’. This burner is one of many objects that will star in Science Underground, curator-led tours of our basement store during Ultimo Science Festival, a feast of activities on offer from 16-28 August 2011.