Light Water at Bannisdale

 

This is the bridge over Light Water at Bannisdale near Kendal. There's supposed to be a parking place here but it was coned off when we went. There is better parking just off the A6 at 545013. The use of Water as a stream name is not common in the Lake District; it is used in the south of Scotland. However, it got us thinking: Light Water as opposed to heavy water. Heavy water is water where the hydrogen is the isotope deuterium - ie the hydrogen nucleus contains a neutron as well as a proton. I was amazed to discover that the concept of light water does indeed exist - it is called deuterium-depleted water. It turns out that ordinary water contains a very small amount of deuterium and any water with less than this naturally occurring amount can be called light water.