Find the iron filings and you’ve cracked the seesaw case

Professor Daw solves another case. PHOTO: GETTY IMAGES
Professor Daw solves another case. PHOTO: GETTY IMAGES
It was far past the time to be off home but Professor Daw remained high up in the Physics Building, some would say in a brown study, but in fact the professor was surrounded by the multi-coloured spines of the bookshelves and the garish splash of the modern art prints which covered the study walls.

Thirty years ago, a timid student taking first steps towards a physics degree, the mysteries of the subject threatened to be overwhelming. "The natural science of matter, involving the study of matter, its fundamental constituents, its motion and behaviour through space and time, and the related entities of energy and force" was how the syllabus put it, and this daunting prescription had the newcomer wondering if something outrageously simple like English or Medieval History might have been a better choice.

But, as often happens in academia, the example of an outstanding teacher, led the faltering steps of the young student on a journey of discovery which was not yet over. The late Professor Lever’s work on the Black Hole had inspired generations of students and convinced many of them that there was more to life than the Captain Cook or playing the trumpet in the Capping Band.

Yes, "the study of matter" had enriched Professor Daw more so than literature of the lovelorn or long-distance examinations of ghosts of old battles and the Black Hole always seemed slightly more cheerful than the Black Death.

Each day physics brought new wonders, fresh challenges and opportunities to be part of the real world.

As these soothing thoughts swirled about they were interrupted by a tinkly rendition of Do The Loco-Motion, the great 1960s’ hymn to physics.

"Hello. Professor Daw speaking."

"Good evening, professor. Detective Sergeant Dick Prowl, Dunedin CID here. We need your help."

A call from the detective came as no surprise. Over the years, Professor Daw had played a part in the wider community. Work on the physics involved in kicking a rugby ball had helped Tony Brown amass 857 points for the Highlanders and more than once the physics of blunt instruments had helped secure an assault conviction.

The professor’s most celebrated success was The Case of the Flying Custard which features in the recent publication, Great Kiwi Crimes of the Twentieth Century.

You may recall the incident. It happened during a royal tour and involved a young man accused of assault when he threw a large custard pie ear-marked for a future king but which landed on a prominent city councillor. A video of the incident convinced the professor that the young man’s aim was awry and the missile had hit a local-body notable who had suddenly leaned over to shake the hand of a constituent.

The professor’s evidence was enough to have the man acquitted. The bench commenting: "This a simply a case of youthful high spirits and the defendant leaves this court without a stain on his character, but with custard on his sleeve."

DS Prowl was agitated. "Professor, we’re baffled. We need your help in the George St Outrage. I’ll send a car for you and meet you at the scene of the crime."

George St was silent. No cars cruised the maze of obstacles. One man was asleep amidst the shrubs and a drunk was talking to a tree. Just another night.

The 'broken' seesaw. PHOTO: ODT FILES
The 'broken' seesaw. PHOTO: ODT FILES
"Here’s what I want you to see." DS Prowl led the professor to a cone-surrounded pile of timber and mechanical debris.

"It was a seesaw, but someone’s had a go at it - $600,000 it cost to set up this play area and we’ll be getting a bit of stick if we don’t find the seesaw saboteur."

"Nice turn of phrase, sergeant, and I see the solution. The physics of a seesaw are simple. As you remember from school, force=load x load distance/effort distance."

"Well, no. I was in the class for slow learners."

"Really? You’ve done well in the force, though. What I’m saying is that a seesaw is simple. For it to break down would need some human intervention. At a glance I can see that iron filings have been inserted at the tipping point. Fatal for a seesaw. Any suspects?"

"No idea. Nothing at police college prepared us for seesaw crime."

"Perhaps you need to explore motive. The seesaw replaced carparks. Who did that upset?"


"Surely you recall the vigorous protests of SOPS?"


"The Save Our Parking Spaces gang. I suggest, sergeant, that you pay a visit to the chairperson of SOPS and check for traces of iron filings on their person. Good night to you."

Well, the professor was right of course and the case will be heard next week. Once again Professor Margery Daw foils those who would challenge justice and fair play.

— Jim Sullivan is a Patearoa writer.