Introduction:
When electrons drift in a metal from lower to higher potential, it indicates the presence of an electric field within the metal. This electric field is created by an external power source, such as a battery, which applies a potential difference across the metal. The movement of electrons in response to this electric field is known as electron drift.

Explanation:
1. Free Electrons in a Metal:
In a metal, the outermost electrons of each atom are loosely bound and are able to move freely within the crystal lattice. These mobile electrons are referred to as free electrons. However, it is important to note that not all electrons in the metal are free electrons. The majority of electrons are still bound within their respective atoms.

2. Electric Field and Potential Difference:
When a potential difference is applied across a metal, an electric field is established within the metal. The electric field exerts a force on the free electrons, causing them to move. The direction of electron drift is from the region of lower potential (negative terminal of the power source) to the region of higher potential (positive terminal of the power source).

3. Random Thermal Motion:
In the absence of an electric field, the free electrons in a metal undergo random thermal motion. They move in all directions with equal probability. However, when an electric field is present, the random motion of electrons is influenced by the force exerted by the electric field.

4. Drift Velocity:
As the free electrons move through the metal in response to the electric field, they experience collisions with the positively charged metal ions and other free electrons. These collisions cause the electrons to scatter and change their direction of motion. However, due to the continuous force exerted by the electric field, the net movement of electrons is in the direction of higher potential.

5. Distribution of Electron Velocities:
While the overall movement of electrons is from lower to higher potential, it is important to understand that not all electrons in the metal are moving in the same direction. The individual electrons have a range of velocities and can be moving in various directions. However, when averaged over a large number of electrons, the net movement is in the direction of higher potential.

Conclusion:
In summary, when electrons drift in a metal from lower to higher potential, it does not mean that all the free electrons of the metal are moving in the same direction. Rather, the individual electrons have a range of velocities and can be moving in various directions. However, the net movement of electrons, influenced by the electric field, is in the direction of higher potential.