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Image: Kathryn George/Stuff
Image: Kathryn George/Stuff

ScienceJune 19, 2023

The mystery of the Air New Zealand scales

Image: Kathryn George/Stuff
Image: Kathryn George/Stuff

The scales at the airport told me my baby weighed 8.2kg. But the set at the medical clinic told me he was 7.5kg. Could the national carrier be charging for excess baggage based on faulty scales?

This story was first published on Stuff.

Think of the last time you used a set of scales. Or purchased something that had been weighed or measured before being packaged.

Perhaps you’ve taken some medication today. Or bought chia seeds at the supermarket. Put petrol in your car. Posted a parcel. Poured cement.

You trust those numbers, don’t you? Of course you do. The Weights and Measures Act sets out rules for selling goods by quantity.

It’s often only when measurement tools tell us something odd we start to notice them.

Like when you use the scales at the airport to weigh your baby. I mean, your bag. Or your baby. And then you weigh him – your baby – again at the doctor’s office and the difference in weight is 700g.

It doesn’t sound like a lot but for an 11-month-old, it is.

Let me explain.

The Air New Zealand scales at Auckland Airport’s gate 28 said my son’s weight was 8.2kg. But the following afternoon, the scales at the medical clinic said his weight was 7.5kg.

Could the airline be charging passengers for excess baggage based on faulty scales? It’s not beyond the realm of possibility. In 2008, an investigation into scales at major UK airports found widespread weighing errors. Ticket counterweights at US airports have also been found to be inaccurate.

I contacted Air NZ’s media team: “Is someone able to explain how the scales are calibrated? Is there consistency across the country?”

A spokeswoman told me the scales are “standard calibration”.

But not all scales, even digital ones, are created equal. To be used for trade they need to be approved and verified.

This is where Mike Adamson, a Trading Standards-accredited weighing scale service technician – or metrologist – comes in.

Adamson is managing director at ScaleLogic Limited, a company specialising in supplying, maintaining and repairing weighing, filling and dosing systems, as well as calibrating measuring instruments across industries. He calibrates and certifies scales from small lab balances in food factories through to 200-tonne silos for weighing grains.

This involves using legally-verified “test masses” of an approved type with an unbroken measurement chain back to the International Prototype of the Kilogram, or IPK.

The IPK, a very special lump of metal stored in France, is part of an often unnoticed international framework, called the International System of Units (SI). It underpins the 20,000 weighing scales in supermarkets around Aotearoa, for example. It ensures you pay for the right measure of chia seeds.

As my colleague Keith Lynch wrote: “The concept of a kilogram is unmoved by politics, disinterested in social media chatter – a dispassionate, unbending foundational truth.”

For those in the know: Yes, the kilogram was redefined in 2019. But I’m not going to go into that here because the IPK is still used for calibrating mass standards around the world.

Every year, Adamson sends his test masses to Trading Standards in Wellington, the agency that administers and enforces the nation’s system of trade measurement. The masses are tested against one of a higher classification that in turn has been calibrated by an even higher classification. And so on, right up to the IPK.

“That’s how you get measurement traceability,” Adamson says.

“Our 20kg weights are verified to an accuracy of ±0.6g which is ±0.003% of maximum permissible error.”

I went back to Air NZ’s media team: “Can you tell me anything further about the process [of calibration]?”

They could – or would – not: “Thanks for your follow up questions but we don’t have anything further to add here, sorry.”

The three NZ primary kilograms that are kept in double bell jars. (Photo: MSL/Stuff)

A week later, my son and I boarded another flight. I weighed him on a different set of Air NZ scales. They said he weighed 8.3kg.

This time, I noticed several stickers on the scales. A “mark of verification” and a “certificate of accuracy” provided by Wedderburn, an Australian scales business since 1896.

National service manager Brent Taylor tells me certificates are awarded by an accredited person and show compliance with the requirements of regulation 20 of the Weights and Measures Regulations 1999. Wedderburn issues in excess of 10,000 a year.

“Every 12 months, we’ll roll up and put a heap of hand weights on those machines and issue them with certificates of accreditation.”

Wedderburn also works with Plunket and other health agencies to ensure their scales are accurate.

I ask whether my son is 7.5kg, 8.2kg or 8.3kg.

He explains the scales at the airport are designed to weigh items from 100g to 100kg. Most paediatric scales have a weight capacity of 20kg and a graduation interval of 10g. Machines in neonatal intensive care units are accurate down to 2g.

“So the airport scales count by a bigger number,” Taylor says. “The paediatric scales will be more accurate for smaller weights.”

That’s assuming they’ve been calibrated correctly. But general practitioners aren’t using their scales to trade by weight. Meaning they don’t need to be trade certified.

“I’d suspect the baby scale your doctor is using mightn’t be 100% correct.”

Hospital scales get tested for accuracy because they’re used to inform medication doses. In my son’s case, we’re simply tracking growth over time.

But to satisfy my curiosity, Taylor arranges for a colleague in Christchurch to weigh my son on a set of new and precise paediatric scales. “They’ve just been tested,” we’re told.

I take off my son’s boots and am assured – with a demonstration involving hand weights – his clothing weighs no more than 50g. We watch the numbers tick over before they stop at 8.03kg.

Finally, we have an answer.

The GP is underestimating my son’s weight while Air NZ may be overestimating it, by a fraction. Presumably, no one is fined for having baggage 200-300g above the limit.

So the next time I want an accurate weight, for my son or myself, I know where I’ll be going.

Keep going!
(Getty Images)
(Getty Images)

ScienceJune 19, 2023

The transformative power of pūtaiao in Māori scientific research

(Getty Images)
(Getty Images)

Before we can Indigenise science, we have to decolonise science, and the pūtaiao model provides a pathway.

We are witnessing a resurgence of Indigenous knowledge and growing acknowledgement of its scientific value worldwide.

In Aotearoa, there’s been some progress, including the introduction of a public holiday to mark Matariki, the beginning of a new year in maramataka, the Māori calendar based on the phases of the Moon, the movement of stars and the timing of ecological changes.

But progress has not been straightforward, with some scientists publicly questioning the scientific value of mātauranga.

At the same time, Māori scientists have drawn on and advanced mātauranga and continue to make space for te reo, tikanga and honouring Te Tiriti o Waitangi in research.

Our recent publication explores pūtaiao – a way of conducting research grounded in kaupapa Māori.

In education, pūtaiao is often simplified to mean science taught in Māori-medium schools that includes mātauranga, or science taught in te reo more broadly. But science based on kaupapa Māori is generally by Māori, for Māori and with Māori.

Our research extends kaupapa Māori and the important work of pūtaiao in schools into tertiary scientific research. We envision pūtaiao as a way of doing science that is led by Māori and firmly positioned in te ao Māori (including mātauranga, te reo and tikanga).

Image: Archi Banal

Pūtaiao as decolonising science

Pūtaiao privileges Māori ways of knowing, being and doing. It is a political speaking back for the inclusion of te ao Māori – mātauranga, te reo, tikanga and Te Tiriti o Waitangi – in science.

Conducting research this way is not new. Many Māori scientists have drawn on mātauranga and kaupapa Māori in their research for decades. Our conceptualisation of pūtaiao is an affirmation of the work of Māori scientists and a pathway for redefining and transforming scientific research for future generations.

Decolonising science is at the heart of pūtaiao. It challenges and critiques the academy and disciplines of Western science. Decolonising science requires a focus on histories, structures and institutions that act as barriers to mātauranga, te reo and tikanga.

We argue that decolonising science is a necessary step before we can Indigenise science.

Like mātauranga, pūtaiao is embedded in place and in the people of those places. It centres, prioritises and affirms Māori identity in the context of scientific research and science identity.

Ngā Pae o te Māramataga research lead Dr Ocean Mercier (Illustration: MsMeemo)

The importance of the researcher in pūtaiao

How we identify as Māori – tangata whenua or rāwaho (people not related to the hapū or whānau), ahi kā (people who keep the home fires burning) or ahi mātaotao (people who may have been disconnected to the land through lack of occupation over generations) – fundamentally changes how we interact with people and place through research.

To practise pūtaiao effectively, researchers are required to understand who they are and how that informs the research questions asked, the research relationships formed, the location of the research and the way research is conducted.

Kaupapa Māori, as articulated by distinguished education scholar Graham Hingangaroa Smith, requires two approaches to decolonisation: structuralist and culturalist.

Culturalist approaches centre te reo, mātauranga and tikanga. The groundbreaking work led by professor of marine science and aquaculture Kura Paul-Burke, using mātauranga to enhance shellfish restoration, is an excellent example of a culturalist approach to decolonising science.

A structuralist approach means paying attention to and dismantling the structures within science which continue to exclude Māori knowledge and people. It encourages us to think about the colonial roots of science and how science has been used to justify colonial violence and oppression of Māori.

Captain Cook’s “scientific voyage” to Aotearoa is a great example of how colonisation occurred under the guise of science.

Challenging the status quo

Pūtaiao reframes the conversation around the inclusion of mātauranga Māori in science. It considers the relationship between te ao Māori, the researcher and science to imagine how to decolonise, Indigenise and transform science.

We understand science not simply as scientific knowledge but as a knowledge system that spans research, education, academia, scientific practice and publications, as well as the evaluation and funding and access to science, its legitimacy and its relationship to policy and government.

There has been much research on Māori experiences within the science system, including the cultural double shift when Māori scientist are expected to lift their colleagues’ understanding, racism and the difficulties of inclusion. A lone Māori scientist is often tasked with upskilling their colleagues, representing Māori on committees and leading cultural practices in addition to standard loads of supervising, teaching and research.

To challenge the status quo, we explored different ways of creating ecosystems or “flourishing forests” of Māori scientists to advance pūtaiao. This includes creating networks of Māori staff in science by establishing research centres such as Te Pūtahi o Pūtaiao and the Centre of Indigenous Science.

It also means creating research projects that move beyond the siloed disciplines within the science system. In this way, pūtaiao enables Māori to see themselves and be seen within science.

Pūtaiao offers a practical foundation, connecting Māori science leaders to transform science. Whether this happens through new university courses, academic programmes, research centres, institutions or regional and community hubs remains to be seen.

It is certain, however, that pūtaiao, conceptualised as kaupapa Māori science, offers many pathways for Māori scientists to continue to draw on and advance more than mātauranga to decolonise and, ultimately, redefine science into the future

Te Kahuratai Moko-Painting is co-director of the Centre for Pūtaiao, University of Auckland. Tara McAllister is a research fellow at Te Herenga Waka — Victoria University of Wellington

This article is republished from The Conversation under a Creative Commons licence. Read the original article.