Principle

The example of sodium thiosulfate shows that additional energy is needed for the melting process. This is shown by the fact that the temperature increases only slightly during the melting process. During solidification this energy is released again, which can be observed by subcooling before solidification and a temperature increase to melting temperature afterwards.

Benefits

• Particularly understandable and didactically prepared description of the experiment (relevance to everyday life etc.) including protocol questions
• Future-oriented teaching: Integration into digital science lessons with tablets
• Increased motivation of students by using the intuitive measureAPP
• Increase of media competence

Tasks

The students heat sodium thiosulfate until it melts and let it cool down again. In doing so, they measure the temperature curve as a function of time with a uniform heat supply or removal.

Learning objectives

The students learn that the change of aggregate state between solid and liquid in sodium thiosulfate requires energy which can be observed in the temperature curve.