Final answer:
The color change in heated iron is due to the energy absorbed by electrons, which move to higher energy levels and then emit light as they fall back to lower levels. Shaking iron doesn't release electrons, but heating provides enough energy for electrons to escape. Iron remains unchanged as an element; only the state of its electrons changes.
Step-by-step explanation:
When you heat a piece of iron, the color changes are due to the behavior of the subatomic particles in the iron, particularly the electrons. Heating the iron provides energy that electrons absorb, allowing them to move to higher energy levels. These excited electrons then release energy in the form of light as they return to lower energy levels, which explains the color changes from red to blue as the temperature of the iron increases.
Shaking a piece of metal does not provide sufficient energy to remove electrons because the energy is not distributed in a manner that would raise the electrons to a higher energy state. However, when the metal is heated, the electrons can absorb enough energy to overcome the binding energy that holds them in the metal, leading to the phenomenon known as thermal emission or 'boiling off' electrons.
Iron atoms do not break down into different elements as they are stable. Only the distribution and amount of energy absorbed or released by the electrons change their state within the metal, affecting its color as seen through the various stages of heating.