On Wednesday we went to a field at Wideford Hill where we met archaeologist Christopher Gee and our friend Mary Saunders from ORCA. Chris showed us how he had marked out the field in a grid of 20m x20m squares. He needed to do this so that a record could be made of where any finds had been made.
Mary showed us how geophysics technology could be used to survey the field and find out what was under the ground. When archaeologists have a picture of this they can decide where the best place on the site might be to investigate further.
The first machine looked at the magnetic field of what was around it, so our metal zips and buttons affected the results. Mary was wearing clothes which didn't have any metal in them so that she could take more accurate readings.
|Telling the machine where NSEW is.|
The next machine send a signal down in to the ground and showed its results in a screen in the form of a spiky graph. We could see where it had detected something quite easily. It was important to move the machine at the right speed and cover the distance of a metre for each beep it sounded.
Meanwhile another group were fieldwalking and found some interesting stones. We could work out interesting information from most of them, though some of it was evidence of quite recent activity.
The GPS system that Mary used was accurate to 6mm. That meant that archaeologists coudl return to the site much later and find the precise place where an object was found.
Many thanks to Mary, Christopher and ORCA and Orkney College for allowing us to meet the experts in the field.