• iceberg
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  • checking water quality
  • planet eclipse
  • rangitoto trees
  • kids with test tubes
  • kids with earth
  • snowy mountains
  • Rainbow Clouds

    Refraction and diffraction of light through ice crystals in the clouds

  • Philippa On The Ice

    Philippa On The Ice Philippa Werry at an Antarctic research camp 2016

New Zealand Science Teacher

Standing Committees

Gunpowder and particle board: becoming a science technician

Ian de Stigter writes about his journey from a young explosives-maker to a science technician supporting student integrity.

I was not a model school student. My form teacher in the fifth form, Noel Woods, moved to another school as Head of English. During my seventh form year, he organised billets for a sports trip to his school. With his customary candour, he proclaimed it as appropriate to billet the most difficult student in his Dargaville class with the most difficult in his class at Rutherford – Tim Shadbolt, now long-serving Mayor of Invercargill (Noel Woods became Principal of Rangitoto College in 1971).

The first interest I recall having in science was in making explosives. I started with gunpowder (using a recipe from a school encyclopaedia), collected charcoal from charred tree stumps, bought sulphur and saltpetre (potassium nitrate) from the Farmers Trading Company, and I was very satisfied with some of the results. Neighbours were less-favourably impressed.

I got into chemical analysis when a pack of saltpetre I bought failed to produce a viable explosive. After a few simple chemical tests, I concluded that the Farmer’s staff had wrongly packaged up some alum (also sold in the shop) in a saltpetre bag. The shop assistant didn’t accept my complaint – what would a schoolboy know? I wondered if others buying saltpetre to cure their meat also found alum somewhat unsuited for that purpose.

Our sixth form chemistry teacher helpfully suggested other explosives that were simply made with available chemicals. One morning as she stepped into the chemistry lab, there was a series of minor explosions underfoot. “OK, who made the nitrogen tri-iodide? de Stigter?”

I had been preoccupied with an attempt to do a little of the homework before class started, so I had missed my mate’s attempt to tell me what was about to happen (I had transgressed in other ways, such as putting calcium carbide down the lab sink, and inserting the plug so that acetylene bubbled out of other sinks). However, I was not the guilty party with the nitrogen tri-iodide.

After two terms of my seventh form year, I was called to the headmaster’s office, along with a classmate. He was forthright with us: the inspectors were coming after the term break; we were an embarrassment to the school because we hadn’t done enough to warrant Higher School Certificate. It was strongly recommended we leave forthwith. We both did.

I found a job in the Hunuas, carrying out physical soil tests for an Auckland City Council dam construction. I stayed only four months, but during the period, I had what I would describe as a personal epiphany, producing a re-evaluation of life direction. One new objective was to get a job closer to civilisation and take on some study. The next year found me working in a wood products R&D lab and studying for the New Zealand Certificate in Science.

Although I was fortunate that the R&D head gave me a fair amount of responsibility, I came to realise that the company culture condemned all those without degrees to second-class status. Others felt the same. When I was farewelled to study at Canterbury University (after completing the NZ Certificate), another technician was also leaving to study at Auckland University.

I did not foresee the decline of the wood products industry, nor the effects on New Zealand manufacture and associated science employment when New Zealand abandoned its protectionist trade policies, nor the subsequent trend to globalisation – which has continued that negative employment trend. If I had, I might have studied something else. However, I chose to study chemistry and wood science. By the time I graduated from university, the wood products sector was already starting to decline. Indeed, when I consider the nature of the R&D our company was doing earlier, and its limited success in bringing forward new products, it could be said that the situation was already shaky during my years in wood product R&D. The wisdom offered by hindsight has few practical benefits!

After university, I worked at a particleboard factory complex, doing mainly product development. However, budgets were tight, and this led to unfortunate compromises. Product that had failed physical tests was routinely shipped out to meet production targets. The workplace exposure limit for formaldehyde was then 100ppm, and this was not routinely monitored. Management refused me permission to test the actual levels. In later years, the exposure limit was reduced to 1ppm and all staff carried personal exposure monitors to ensure compliance, and non-complying plants were shut.

I became, for ten years, a technical manager for a gas company, during a period of major change and developments in reticulation, in LPG production and CNG use in vehicles, and in methods of operation. I had a role in some technical innovations, and in applying quality management principles to improve procedures. However, at the end of the period, the company had fewer operational and staffing requirements. My role was redundant. I spent several months on carpentry, painting, and roofing work, while seeking another science role.

A government department that offered testing services to mainly food producers hired me as an analyst, and I remained there for 11 years. This gave me opportunities to use a range of analytical techniques and sharpen some practical skills. Most of that food testing experience is difficult to relate to my subsequent role in a school, but there are three particular things that I have since found very useful. The first of these was the need to develop really good skills in using a manual burette, which I used there for tight-tolerance analysis of a variety of raw materials added to food. The second one was the opportunity and need to verify the accuracy of volumetric glassware – burettes and pipettes. The third was the pouring of agar plates for bio cultures.

This government department lab was also undergoing changes: in its clientele, technology, test turnaround times, cost structures, and eventually, ownership. Shortly before it changed to a state-owned enterprise model, I found myself looking for a new employer. A professional colleague who had retrained as a science teacher invited me to apply for the science technician role in his school.

One challenge I faced soon after I began working at Mt Albert Grammar was preventing students cheating during chemistry practical assessment. Some students arriving at Mt Albert Grammar as seniors had a strong academic record, with high family expectations of them, but with limited practical experience and skills. The chemistry teachers have done their best to remedy skill deficiencies, but students also need to know that there are no attractive shortcuts to success.

My response to a couple of blatant cheating attempts has been to ensure further attempts at cheating are unlikely to succeed. Each student gets a numbered sample, has no way to know how many different sample values there are, but faces a high probability of failure if he/she uses another’s test results. This means more technician work in accurately establishing what each of these expected values should be, but that investment needs to be made. Together with the use of calibration errors established for volumetric glassware used in titrations, this gives us every reason for strong confidence in the integrity of student work and its assessment.

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