A ruler: a convenient way to measure 30 cm. Image by Mags_catThere s a company based in the US, which specialises in science education supplies. I have had reason to purchase many items from them over the years and I have always felt that the service is good and the range extensive. While browsing their site a few days ago, however, I stumbled upon an item that is just silly. Actually I can’t decide if it is brilliant or ridiculous. You can make up your own mind.

It’s called the “nanosecond bar” and is described as a “durable, three-dimensional bar”. It is designed help students understand how fast light travels. With the rise of nanotechnology and especially with the proliferation of the term, I have had reason to explain to students (and also just at parties) issues of scale and the nano-scale in particular. I was, therefore interested in this exciting product.

It is a pale blue piece of plastic, 30 cm long, about 2 cm wide and perhaps 3 or 4 mm thick. It has the words “one nanosecond” written along it. That appears to be all there is to it. The idea is that it is exactly 30 cm long – the distance light travels in a nanosecond. It’s basically a plastic ruler – without measurement markings along it. Surely a ruler would suffice, or a 30 cm piece of string, or 2 correctly positioned hands, or a line in the sand.

Perhaps I’m missing the point, but for a little less than $8, I wonder if there aren’t better options.