Okay, so this is the red and blue electron-file demonstration. It's a demonstration which you can use to visualise your students a redox reaction. In this demonstration you'll see the build-up of a red and blue substance near to nails stuck in a special gelatin solution. So it's an example of the electrolysis. It's a very colorful example obviously. The gelatin in question is just ordinary gelatin but to that we've added a dilatant solution of potassium very cyanide and a little bit of fennel failing in about 10 drops. And so it's just you make it probably the day before. Obviously you just with a bit of warm water, the gelatin it'll set. I think in a handout we've set how to make about three or four of these. In our experience they actually can last up for about three or four days so you can make a few in advance. You then put two nails into the gelatin and attach it to a power supply at six volts and turn that on. And at start, first few seconds it doesn't look much as happening but as we know very quickly you'll start to see a bit of a bit of pink thickness on sort of around one of the nails and a blue substance around the other. And along you'll see this the more that will build up. And if you look really carefully and get students can get quite close to this one. You'll see some bubbles starting to form actually in, it's seeming to be bubbles embedded inside that pink. So that's that pink trail. Now in terms of what's happening in terms of the chemistry. So at the cathode you have reduction. Water is being reduced to form hydrogen gas and hydroxide ions and that will react to the fennel failing and of course the surrounding the area surrounding the nail to turn pink. The idea is that at one of the electrodes oxidation is going to take place where the iron nail is going to turn into iron 2 plus. When the iron 2 plus is formed it will form a metal complex with the ferrous cyanide present and form a blue complex. It's basically an iron complex and iron iron complex and a better, it's however better known perhaps in society as turn blue or Prussian blue. Sort of one of the first artificial blue sort of colours we were able to make. A very impressive bright blue colour. So in terms of questions you could ask your students you could talk about just experiencing that yellow pink indicates that hydroxide has been produced and maybe they're not some for looking at an electrochemical series. What might be reacting to produce hydroxide ions and then you can draw it from them that it's water being reduced and then maybe they draw out if it's reduction is it the anode or a cathode and similarly you can point out that the blue indicates that iron 2 plus has been formed so maybe then talk about what's been oxidized to form that and yeah again does it occur at the anode or the cathode. At the cathode it's easy to link this to corrosion prevention so using impressed current techniques where electrons are supplied to an an ale or to any metal to stop the corrosion of that metal and so in this case you're supplying electrons through a power supply you're allowing reduction to occur at the nail and preventing it from being oxidized by supplying electrons. As you remove the nails the colours that were formed stay present and you can observe where the electrons have moved or where things have been reduced and oxidized. You can see the blue and the pinks that are trail going down which is a very impressive look. So yeah great demonstration to show visually an oxidation reduction reaction for your students.