Observing Latent Heat with a Portable Hand Warmer

This teacher-directed demonstration provides a conceptual understanding of latent heat. Using the example of a chemical hand warmer, students learn about phase changes from liquid to solid and from solid to liquid and observe that one of these phase changes releases heat while the other requires heat to be added. These concepts are then reinforced in a demonstration which involves heating water and ice water. Evaluation suggestions are also included. Educational levels: Middle school, High school