## When the power goes off

This morning we woke up to discover  a power cut. This meant: No electric kettle. We do have a gas stove, however, which we could light with the help of matches (the automatic ignition relies on mains power.) So we did eventually get some hot drinks. No toaster. No microwave. No hot toast, no porridge.  […]

## The lying dashboard (part 2)

Following-on from my suspicions as to the accuracy of my car’s reporting of my travel statistics, here’s another mystery. The length of my journey from home to work, as recorded by my odometer this morning, was 24.7 km.  The length as recorded by Google Maps is 25.2 km.  So, my odometer underreads. Or it did […]

## Student evaluations of teaching effectiveness tell us nothing about teaching effectiveness

I thank my colleague Chris Lusk for bringing this paper by Uttl, White and Gonzalez to my attention. Many universities and polytechnics acquire Student Evaluation data on courses and teacher quality at the end of a course. There are different ways this can be done – here at The University of Waikato students are asked (online) […]

## The lying dashboard

How accurate are our car speedometers? That’s well discussed., e.g. on this AA question forum.  If the ‘expert’ here is correct, your car speedometer could over-read by as much as 10% + 4 km/h (which is quite a bit – if you are doing 45 km/h it might read 54.5 km/h, or if you are […]

## Quantum cryptography

I was reading last week a children’s book about “Secret codes”.  You probably know the kind of thing I’m talking about – substituting one letter for another, or a squiggly shape for a letter, rearranging letters, and so on. Fun things to do, but not the basis of modern cryptography. However, the book didn’t just […]

## Language in physics teaching

Hello everyone. It’s been a long while since I was blogging, but I am back again now. The second-half of the year is rather less hectic for me, so I have some time to get back to this. I’ve been considering recently the learning that students have achieved in our first year paper “Physics in […]

## The bed of nails

It’s always fun to see this demonstrated. Here’s Haggis Henderson, at the recent NZ Institute of Physics conference in Christchurch, not only lying on a bed of nails but having a teenager stand on him too. He survived the experience, though I can’t vouch for what his back looked like afterwards. The bed of nails […]

## An optics puzzle

Here’s a genuine photograph of a pair of eggs, waiting to be omletted. (Okay, that’s not really a word.)   What has happened to their shadows?