• Question: How was the lemon taste generated on the two contacts in the boys mouth and then enhanced by by another unit

    Asked by Anon on 5 Jan 2015.
    • Photo: Wallace Viguier

      Wallace Viguier answered on 5 Jan 2015:

      I would love to be able to answer but can’t find the video you are reffering to. Can you tell us what episode this was in and at what time in the episode?


    • Photo: Fiona Dickinson

      Fiona Dickinson answered on 6 Jan 2015:

      I’m not sure why it was a lemon taste but I can in part answer this…

      First off taste and smell are linked (did you ever notice food doesn’t taste as good when you have a cold? this is because you are missing a lot of the smell information), by adding smell you make things taste better… infact our tongues aren’t great at tasting the difference between things we need our smell to add the detail to tell the difference between beef chilli and lamb curry for instance…

      Now the two contacts thing, I’m not 100% sure how it worked on the show but as a chemist I think about everything in terms of moving around electrons, and two contacts and a battery to me stay moving around electrons. You can also do this without the battery but you need to have had a filling (one of the silver amalgam ones).

      If you have a filling bite down on a little piece of copper (some copper wire if you have any or a coin (give it a wash) and you will feel a weird sensation (sort of tingly) and a sour taste (which could be lemons as they are sour). The metal in the filling is a different metal to the copper and so electrons are moved between the two, as the electrons are moved they give you the weird taste. I assure the two electrodes are a way of getting the same effect without the need for bad teeth 😀

    • Photo: Tim Stephens

      Tim Stephens answered on 7 Jan 2015:

      Your tongue can only sense a few flavours: salt, sweet, sour and bitter and each of these tastes is associated with a specific area on the tongue.

      My _assumption_ is that the electrodes excited one particular area (the one that is associated with sour tastes). As Fiona says, lots of taste is actually to do with your sense of smell, so the smell of lemon (not sure how they did that) would enhance the sour sensation that the electrodes produced.

    • Photo: Kate Mulcahy

      Kate Mulcahy answered on 7 Jan 2015:

      The electrodes that were placed on the tongue excited the nerve endings in the tongue to produce the sour tingly taste on the tongue.
      They then used a small device which emitted a puff of lemon scent. This device emits tiny droplets of a chemical that react with the nerve ending in your nose and cause you to smell lemon.
      Because there are many different elements involved in tasting adding the lemon smell to the tingly sour reaction on your tongue would make the experience more realistic.