By the end of this lesson you will be able to: - Identify the purpose of SI. - Identify the SI units of length, volume, mass, temperature, time, and rate. SI Units What is SI? Why was it created? SI uses the metric system, which makes conversions easy, as they are multiples of 10. When multiplying by 10 what happens to the number? In your groups try the following conversions by multiplying by a power of 10 and moving the decimal. Use Table 2 on page 50. 3 Gigameters are how many meters? 7 hectometers are how many meters? 1000 millimeters is how many meters? Think about it: How many inches are in 17 feet? Which was easier to calculate, the metric conversion or the American system? Fill in the following chart as you read. Type of measurement Definition Distance between 2 points SI Unit Amount of space occupied by an object The amount of matter in an object Measure of gravitational force on an object How hot or cold and object is Interval between 2 events Rate – Homework: On a separate sheet of paper answer self check questions 1-5 on page 54.