October 13, 2009
Enhanced Gizmos feature chemistry and evolution
As a part of our ongoing project, six more science Gizmos now feature enhanced curriculum materials (Student Exploration sheets, Answer Keys, Teacher Guides, and Vocabulary Sheets):
Rainfall and Bird Beaks (metric version)
That brings our total up to 60 enhanced Gizmos since the start of the year. Phew! We hope you enjoy these materials and take advantage of all the great teaching ideas and activities that they offer. Enjoy!
October 09, 2009
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!