Answer
The ice under the wire gradually melts because of the increase in pressure on the ice as the wires are attached to heavy weights. But when the wire moves down the ice block, the water above the wire refreezes because as the wire moves down, the pressure on the water above the water is reduced and the water refreezes to ice. That's why the ice block is not cut into two.
Work Step by Step
The ice under the wire gradually melts because of the increase in pressure on the ice as the wires are attached to heavy weights. But when the wire moves down the ice block, the water above the wire refreezes because as the wire moves down, the pressure on the water above the water is reduced and the water refreezes to ice. That's why the ice block is not cut into two.