1) (a) Which phenomenon can be studied by following diagram?
(b) Define that phenomenon which is related to above experiment.
(c) If crushed ice is pressed and then the pressure is released, a lump of ice
is formed. Justify it.
Answers
REGELATION
a) The given diagram demonstrates the phenomenon of regelation.
b) Regelation is the phenomenon in which the melting point of ice decreases due to an increase in pressure, and goes below 0°C.
On releasing the pressure, the water molecules formed by the melting of ice solidify again to form ice.
• In the experiment shown above, we see a wire kept on the surface of ice, tied to two heavy weights.
• Due to these heavy weights attached to it, the wire applies pressure on the surface of ice, since P = F/A.
• Due to the increase in pressure, the melting point of ice decreases below 0°C , and the ice starts melting at the point of contact of wire.
• But this water soon refreezes into ice as the pressure on the upper layer is released when the wire moves down further in the ice cube.
• Thus, in the end of the experiment, it is seen that the ice block remains as it is with the wire hanging in the middle.
c) If crushed ice is pressed and then the pressure is released, a lump of ice is formed.
• This is because when crushed ice is pressed, its melting point decreases, and it melts into water.
• Further, when pressure is released, the water molecules coalesce with each other through hydrogen bonding and refreeze into ice.
• Thus, a lump of ice is formed from crushed ice.
a)
The phenomenon which can be studied by given diagram is Regelation.
b)
The phenomenon in which ice converts to water when pressure is applied and reconverts to ice once pressure is removed is called Regelation.
c)
1. When crushed ice is pressed, its melting point is lowered and some ice melts to form water.
2. When pressure is released, the melting point becomes normal and the water freezes to form ice forming a lump.
Hope it helps!