Learning Chemistry is like learning a new language—a language that will help you understand and communicate with the world around you in a new and exciting way. It reveals a world beyond what we can see and know with our eyes alone. It is also about you. The sea as seen in this photo is swimming with fi sh, but it is also swimming with molecules—oxygen, hydrogen, carbon dioxide and much, much more. Have you ever thought about the seasons and the chemical changes that occur in each one? Chemistry can explain how and why the world around you is changing. Like the leaves in this photograph—caretenoids are responsible for the brilliant reds, oranges, and yellows. Chemistry is also a tool—a tool that can be used to help you and the world around you. For example chemistry makes it possible to produce and recycle plastics like the polyethylene water bottles pictured here. Plastic water bottles play an important role in distributing water across the world and recycling those plastics plays a role in preserving the environment.