This is a toy we have shown before on our YouTube channel, but we have never been able to offer it for sale, as we have not been able to find anyone who made it. So in the end, we decided to make it ourselves!
George has been busy in his shed with his lathe, and we are pleased to now be able to offer this fun piece of physics.
Please bear in mind that this comes as a kit, and while there is no construction involved, you will have to make up a salt solution, ideally with de-gassed water, and do a little bit of trial and error with the concentration of the salt solution, in order to get this to work correctly.
The kit includes the main acrylic tube, and the two ends, which are push fit. We also supply the sand timer, which we have tested, and we supply an estimated strength of the salt solution that you will need to make up.
You will need to supply water, table salt, and some time and patience!
In case you need an extra 'O' ring, here are the details - Nitrile 70 rubber 'O' ring, 2mm x 21mm