Sorry about the gap in activities – I had something unexpected come up which was rather more important and urgent than writing blog posts. More or less back online now.
A couple of weeks ago we had our University Open Day, at the University of Waikato. This covered the whole university, and, of course, our department put together some displays and activities on physics and engineering. Perhaps the highlight was a demonstration of a range-imager. As people walked into the lab, where the main displays were, they were confronted by a large screen with their silhouette projected onto it, ‘live’. And, next to their silhouette, were a couple of numbers, one giving their height, and one their distance from the camera. All this updated in real time, and able to handle several people in the field of view at once, all moving about. Pretty impressive.
Except, that as I watched visitors to the lab, they didn’t really dwell on it. Maybe this kind of technology isn’t all that far removed from what everyone is used to nowadays – mobile phones that do far more than just phone are used by people without them batting an eyelid as to what is going on inside them. Instead, what people most loved, were the old favourites – the Van Der Graaf generator (it wasn’t a good day for it though – too much moisture in the air) – the superconductor floating above a magnet, and the liquid nitrogen rocket (Put a bit of liquid nitrogen in a plastic bottle, ram in a cork, and retreat to a safe distance). These are all demonstrations of fairly straightforward physical phenomena, explicitly electrical charge, magnetism and pressure / conservation of momentum. These simple phenomena (especially charge) underly so much of modern technology, but not necessarily in a readily visible form. Possibly this is why their demonstration, in a simple manner, is so gripping.