Remodeled Phase Changes Gizmo

Prompted by a note from a teacher, we have made changes to the Phase Changes Gizmo. In the original Gizmo, we assumed a "no stirring" scenario in which heat applied to the bottom of the beaker was transferred to the ice through natural convection -- the water heated by the burner naturally rose to melt the ice. This scenario resulted in an average water temperature above zero, even while some ice was still present.

We decided to switch the model in the Gizmo to assume "constant stirring." In this scenario, used in many textbooks, lessons, and labs, heat from the burner is instantly transferred to the ice. Noo heat is transferred to the water until all of the ice has melted. As you can see in the revised Gizmo, this results in a heating curve that is perfectly flat during melting, just as in freezing and boiling.

We hope that this change will make this Gizmo easier to understand and use. If you have comments or suggestions about any of our Gizmos, please send them in!