Answer:
Its temperature is increasing.
Explanation:
The temperature of the steel bar is most likely increasing, this way it is gaining more heat energy probably by conduction/convection/radiation.
When temperature changes heat energy is generated. A body increasing in temperature will have its molecules moving more faster tending towards a liquid form if solid originally.
This is as a result of the molecules of the bar gaining more energy and vibrating in their fixed lattice before they eventually break off and flow readily.
