Final answer:
The Ekman spiral is typically demonstrated using a tank of water as a common household item to visualize ocean current movement at various depths.
Step-by-step explanation:
The Ekman spiral is a concept in oceanography and physics that describes the speed and direction of the flow of ocean currents at different depths. In educational settings, it is common to demonstrate this phenomenon using analogies or simplified models. A typical common household item used in demonstrations of the Ekman spiral is a tank of water. By adding dye and using a spinning tool to create rotation, one can visualize how the water at different depths moves in response to forces such as wind or the earth's rotation. This simulates the spiral effect in a simple and understandable way.