An inside-out snowman

Un-lit Snowman

I made an inside-out snowman from two integrating spheres. Below is a picture and line drawing to show the insides. This is also a personal tribute to the work of Rachel Whiteread, who amongst other things produced an inside-out house, and a library as a memorial to the victims of the holocaust. The snowman’s body is made from two integrating spheres joined at two open ports. The arms are tubes that we use to pass gas into and out of the larger cell. The hat is made of pieces of SpectralonTM (see below) and the scarf is an electrical cable Continue reading

That darn vortex ring

In retrospect we could have made this look a little more professional

Despite a  plea to the internet community at large in a previous posted titled “Vortex rings – suggestions please” no one came forward with any explanation of my splitting vortex rings. As popular as our little blog is, it wasn’t popular enough to reach any fluidics experts that could help us. To be honest, I had written this whole problem off a while back and that post was my last attempt at getting an answer before filling it into a folder on my computer called “things to solve when time = ∞”, a folder that is growing to slowly fill Continue reading

Building a simulated oil leak generator

As part of our subsurface oil spill project I have been working on the development of simulation rig to demonstrate the sensor in schools. At the moment the sensor is already stable is water and response well to localised oil in water so the kit is mostly about showing that effect visually. My first video (below) shows me testing our initial set up to see if we get a good flow rate from the end of the buried sample tube into the water. In this video I’m simply using food dye as it shows up well and will give us Continue reading

Brewster angle Lego microscope

Lego BAM

Brewster’s angle is the angle at which light of a certain polarisation won’t reflect off a surface. The resulting reflection will then be made up of only light from a single polarisation (p-polarised). This little optical quirk is how polarised lenses remove lots of scattered reflections in photographs and why polarised sunglasses are so much better when lounging by the seaside. However, rather than just being something that makes sunny days even better, it also provides a neat trick for visualising things that would otherwise be invisible to other analytical methods. Brewster’s angle for water is approximately 53.1°, which is calculated Continue reading