All the data is noted. First-year sea ice consists of fresh ice with large pockets of brine. The density can be quite high. When it is melted, the salinity is measured and recorded. Salinity is determined by measuring the electrical conductivity of water.
Pure water has very low conductivity and seawater has high conductivity.
A probe is placed into each container of the melted 10-cm. piece of ice core. This data is recorded. By having two sheets placed at right angles, no light will pass through. The amount of liquid salty brine remaining in the ice. From brine volume, strength is determined from an equation developed by the strength of ice and relating it to the brine volume.