Marcus Wilson

Dr Marcus Wilson is a lecturer in the Engineering Department at Waikato University and author of the Physics Stop blog. His current research involves modelling of the electrical behaviour of the human brain during natural sleep, focussing particularly on the transitions between sleep states. Previous research interests include infra-red physics and signature control (stealth) and quantum Monte Carlo methods. He graduated from Cambridge University in 1992 (BA Hons) and completed his PhD at Bristol University in 1995.

Improving gender balance in physics - Physics Stop

Apr 07, 2017

The Institute of Physics has just released a report on recent interventions designed to improve the uptake of physics at ‘A’-level by girls*. Although there have been considerable efforts in the UK to improve the gender balance over two decades, there has not been any substantial change – about 20% of a typical A-level physics class is female. Why is this? In the latest study, three different methods were trialled. While they all had modest impact on their own, a much greater effect was observed when all three methods were used together. You can read the details in the report, but briefly, the three approaches were as follows: 1. Developing girls’ confidence and resilience. Previous research had found that boys often consider their own successes as being down to their own hard work and skill, … Read More

Bell ringing: inertia and resonance - Physics Stop

Apr 05, 2017

Only a week more to go in Perth. Time here has gone so quickly. It’s then off to UK for Easter to see my family before returning to Waikato. On Saturday we had a tour of the bell tower on the waterfront. It’s a great looking structure (in my opinion) – and houses the original peal of bells cast for St Martin-in-the-Fields in London. Swan Bells, Perth, Western Australia. Wikimedia / SeanMack. Just how they came to Perth is a bit of a long story, but they had to be removed from St Martin’s because they were too heavy and were causing serious structural damage to the tower. Now they have a new home, along with a great many other bells. Collectively they are called ‘The Swan Bells’ – in Perth naming something is easy – … Read More

The indeterminate cheese flake - Physics Stop

Mar 30, 2017

A couple of days ago I arrived ‘home’ to discover our local ant colony at work. There’s a nest located somewhere in the bushes at the front of our temporary home, and the occupants have become rather adept at raiding our kitchen. Anything left on the kitchen bench is fair game for the taking. Ants are amazingly strong for their size – any little bit of food like a small oat flake gets picked up and transported back to the nest. Now, in this case the ants were after the grated cheese. Some sizeable flakes had been left on the bench and these were going to be a feast for an ant colony. By sizeable I mean something you get from a coarse grater – perhaps 3 mm wide and maybe 2 cm long. Now, to get them off … Read More

More to sundial than meets the eye - Physics Stop

Mar 22, 2017

Sundials are fun. As someone who visited a lot of stately homes  as a child (usually under duress), I found sundials in the gardens a welcome distraction from the monotony of trudging round a place with no other redeeming features that adults somehow seemed to find attractive. Not all adults did, I’m sure, but certainly my parents did.  First, there’s always the question of whether the sun will be out. And if it isn’t out now, will it be out soon? How long do I wait for the clouds to clear? Then there is the deciphering of the roman numerals on the dial, and the question of whether to adjust an hour for British Summer Time. Then comes the excitement of whether the sundial is actually telling the correct time. The answer was usually ‘no’. Even when a sundial is … Read More

Physics is a science. Or maybe not. - Physics Stop

Mar 14, 2017

A couple of hours ago I gave a talk to the ‘education group’ in the Faculty of Engineering and Mathematical Sciences at the University of Western Australia. Broadly speaking, the audience was a group of physicists and engineers who are interested in education. I recycled a talk that I’d given a couple of years ago on the role of mathematics in physics – specifically comparing and contrasting how practising physicists and students think about how maths works within physics. My conclusion from the research I’ve done (based on interviewing students and physicists (you can read it in the Waikato Journal of Education here) was that many students find the statement ‘Physics is a science’ difficult.  They would rather prefer to re-write it as ‘Physics is applied mathematics’. Now, by science here, I mean a body of knowledge based … Read More

Weather records - Physics Stop

Mar 11, 2017

I came across the following on the BBC website  “Australia’s summer broke 205 records…” It draws from the recent Climate Council report. The BBC article doesn’t list them all 205 of them, but does pull out the most impressive – the hottest summer on record for Sydney, Brisbane and Canberra,  and the wettest on record for Perth – a whopping 193 mm. Let’s put 193 mm over 3 months into perspective. Hamilton, NZ, gets (according to metservice.com) 280 mm of rain on average over December to February. A Perth record-breaker would still be called a dry-ish summer back at home. But locally, Perth averages 40 mm over the three months. Also, of that 193 mm, the majority fell in just one day, soon after we arrived here – 112 mm fell on 9 February. That’s … Read More

Jewel Cave: Blowing potholes - Physics Stop

Mar 07, 2017

As part of our trip southwards last week, we visited one of the many caves scattered across the Margaret River region. The immediate impression on entering the ‘Jewel Cave’ is its vast size. It’s hard to estimate just how big the main cavern is, but as a rough guess maybe 100 metres by 50 metres by 10 or so metres high – probably higher in places. The guide told us we had walked nearly a kilometre on the tour and climbed up and down 500 steps as part of it. There’s a lot of volume to it. The cave was discovered only relatively recently, in the 1950’s (from my memory of what the guide said). What drew people’s attention to something special was the ‘blow hole’ on the surface. There is only one natural way into the cave, … Read More

Trusting someone’s engineering calculations - Physics Stop

Mar 03, 2017

We put our trust in someone else’s calculations and measurements all the time. It’s just part of the modern world. Cross a bridge, drive a car, use anything electrical, and we implicity trust that the people who designed it, built it, installed it and tested it have done their job correctly. Occasionally things go wrong and disaster strikes, but, by and large, the things we make use of in our lives work properly. That said, do you fancy trusting the people who designed and installed the ladder up the Gloucester Tree, at Pemberton? This was originally built as a fire lookout, amongst the majestic Karri trees of south-west Western Australia. But now it’s a tourist attraction. People come to climb it, or to watch people climb it (as we did).  I was happy to go up to … Read More

Physicsstop back in business - Physics Stop

Feb 07, 2017

I have been rather conscious of my looonnnnggggg absence from the blogosphere. That really is down to other commitments getting in the way, and then falling out of the habit of blogging.  Hopefully this will be a restart. I have a good opportunity here – I have just started a period of study leave (what used to be called Sabbatical in the old days) and arrived this week in Perth, where I’m visiting the University of Western Australia. I’ll be here for nine weeks – a fantastic chance not to be interrupted by people knocking on my door (and, yes, to develop some research ideas too, I should add). So, first stop, naturally enough when you have a four-year old, is the local playground. And what a playground it is too. It’s been set-up to blend in with the trees … Read More

Video: laminar flow, microorganisms and mangroves - Physics Stop

Jun 21, 2016

This movie is a demonstration of laminar flow. My colleague Julia Mullarney used it last week in our Osborne lectures to high-school students to demonstrate what turbulent flow ISN’T. Video showing Laminar Flow and demonstrating fluid flowing in layers. This apparatus was developed by John DeMoss and Kevin Cahill of the Department of Physics & Astronomy, University of New Mexico.   Basically, laminar flow is time-reversal invariant. This implies a few things, but, notably here that if you reverse the processes involved you get back to where you started with. Motion of micro-organisms This is the problem that micro-organisms face when they move. Any motion that has time-reversal symmetry (like a swimmer kicking their legs, or a scallop shell opening and closing) will get them nowhere. The solution for the micro-organism is to rotate a flagellum (or … Read More