The foam to move in a circular motion B convection . Therefore , B convection is correct.
The movement of the foam in a circular motion in boiling water is primarily caused by the process of convection.
Convection is the transfer of heat through the movement of fluid particles, such as liquids or gases.
In this case, the boiling water serves as the fluid medium.
When the student drops the solid piece of foam into the boiling water, heat is transferred to the foam by conduction, which is the direct transfer of heat between the solid foam and the hot water.
As the foam absorbs heat, it becomes less dense and expands.
The less dense foam then rises to the top of the container due to buoyancy, where it is pushed to the side by the upward movement of the boiling water.
Once at the side, the foam begins to cool down as it moves away from the direct heat source.
As it cools, it becomes denser and eventually sinks back to the bottom.
This process repeats, creating a circular motion as the foam alternates between rising and sinking due to changes in density caused by the heating and cooling cycles.
While evaporation is also occurring in the boiling water, it is not the primary cause of the foam's circular motion in this scenario.
Evaporation involves the transformation of a liquid into a gas, and while it contributes to the overall dynamics of boiling water, convection is the dominant factor influencing the foam's movement.
Question
A student drops a solid piece of foam in boiling water. The piece of foam rises to the top of the container, gets pushed to the side, sinks to the bottom, and then rises again repeatedly. What causes the foam to move in a circular motion? A conduction B convection c . evaporation