Physics tries to answer the bottom-line questions: What? and Why? when we see things in nature that are not understood. For instance, why is the sky blue whereas sunsets are red? What happens when a star explodes? What is radiation? What causes an aurora? Physics also involves the application of this knowledge to other fields. For instance, if you really understand about lasers then you will be better placed to develop new uses for them in applications such as communications, engineering and medical science. Often students take a degree in Physics because they have a particular career in mind, but for many their first priority is simply to understand Physics. They take Physics because it interests them.