In "Lesson 0" of this weather unit, students explore what factors make up the weather and how scientists measure them. They describe the weather at the moment and then view a weather forcast to help them brainstorm a list of elements of weather. The discussion may unearth misconceptions, such as, weather happens in the sky, or if it is muddy or snowy, weather happens on the ground. Students begin to think about weather tools by exploring the use of a thermometer and the difference between Farenheit and Celcius. At the end of the lesson, the class contemplates why weather is important in their daily lives. The study (or review) of weather concepts is an important first step in understanding climate. It will be important, as the unit progresses, to help students distinguish between weather (the condition of the atmosphere at a certain place and time) and climate (the typical weather of an area, averaged over years).