A unit that addresses the sheer volume of incomprehensible numbers (speed, distance, age) in the natural world, helping students to understand the scale of the world using the concepts of rates, proportions and dimensional analysis. Students learn to calculate problems such as: Measurements indicate that the continents of Europe and North America are separating (plate tectonics) at the rate of about 2 centimeters per year. If Columbus could repeat his famous voyage of 1492, about how many feet or yards farther must he travel?