Tuesday, 3 September 2013

Spring tides

We went to Silloth for chips a couple of weeks ago. The tide was out further than I think I've ever seen it. The were sand banks visible that I have never seen before.
 


It had been cloudy in Cumbria but the following night in Cheltenham I noticed that there was an almost full Moon. It's the white globe in the middle over Cleeve Hill.

 
The two things are not unconnected. It is logically obvious that when the Moon and the Sun are on the same side as the Earth, their respective pulls on the water will add up to make a bigger bulge - so higher tides but low water will be less. What is less obvious is that they do the same thing when they are on opposite sides of the Earth but still in line. This is the case with the full Moon. It's called a Spring Tide as in springs of water open up, not the season. I've still not fully grasped how the fields add up when the pulls seem to be in opposite directions but there's something for me to work on this autumn!