This practical is most sensibly done as a demonstration unless you have a freezer big enough to freeze several large blocks of ice.
A large ice cream tub is perfect to fill with water and freeze.
The ice block is placed between two tables or blocks and a length of thin copper wire is placed across the middle (see Fig 1) Masses are added equally to each end of the wire and are left to hang.
The high pressure of the thin wire lowers the melting point of the ice so the ice melts and the wire moves down through it. The water above the wire may refreeze as the pressure ceases.
Snowballs use this principle as when we squeeze a handful of snow, the outside melts slightly. When we stop squeezing, the water refreezes so the snowball holds its own weight.
Ice cubes can also be squeezed together for a few seconds and then released to achieve the same effect.