In this laboratory setup for distillation, where does the vaporization take place?

Explanation

Distillation is described as a two-step process: Vaporization → Condensation. For vaporization to happen, you need a heat source. In a laboratory, this heat is applied directly to the round-bottom flask containing your mixture. As the liquid reaches its boiling point, it turns into vapor and rises. The rest of the equipment is simply there to guide that vapor (distillation head), measure it (thermometer), and cool it back down (condenser) so you can collect it as a pure liquid in the receiving flask.