Changes - Presentation

In a chemistry-focused presentation titled "Changes," students are invited to explore the transformative world of substances. They are prompted to consider whether substances can undergo changes and to identify different methods through which these changes can occur. The presentation aims to help students describe features of various substances and understand the processes behind their transformation. The lesson begins with a simple yet effective experiment involving an ice cube tray. Students are asked to predict what will happen when water is placed in a freezer, leading to a discussion about the states of matter and the transition from liquid to solid and vice versa.

Building on this concept, the presentation delves into the properties of ice, questioning its state as a solid or liquid and the substance it is made from. Students learn that by applying heat or certain chemicals, they can expedite the melting process of ice. This concept is further explored through practical activities, such as finding the quickest way to melt ice and observing the effects of hot water on it. The lesson also touches on irreversible changes, illustrated by the process of making toast from bread, highlighting that some chemical reactions are one-way. The session culminates in a hands-on cookie-making exercise, where students experience first-hand how varying ingredient amounts can lead to different outcomes and that baking represents a chemical change, transforming dough into cookies—a change that cannot be reversed. Throughout the presentation, students are encouraged to reflect on the nature of chemical changes and how they relate to everyday life, reinforcing their understanding of the fundamental principles of chemistry.