1.  Metric System  (international system of units or SI)  - A decimal system (based on 10) that scientists and everyone else in the world uses, except the U.S.

2.  Meter - basic unit of length. A little more than 3 feet. Use to measure a room.  Kilometer - = 1000 meters. Use to measure long distances. About 2/3 of a mile.  Centimeter - 100 cm = 1 meter. Use to measure smaller objects, like a bird.  Millimeter - 1000 mm = 1 meter. Use to measure even smaller objects, like the pupil of an eye.  Micrometer - 1 million = 1 meter. Use to measure microorganisms.  Nanometers - 1 billion = 1 meter. Use to measure very small organisms, like viruses.

3.  The amount of space an object takes up is called its volume.  Liter - (L) the basic unit of volume in the metric system, slightly larger than the quart.  Milliliter-(mL) 1/1000 of a liter: 1000 mL= 1 L  Use L and mL to measure liquids and gases.

4.  Kilogram - (Kg): a little more than 2 lbs.  Gram - (g): 1/1000 of a Kg. 1000 g = 1 Kg  Milligram - (mg): 1/1000 of a gram

5.  Mass is not equal to weight  Mass - the measure of the amount of matter in an object. Is constant  Weight - is a measure of the force of attraction between objects due to gravity. Is not constant.

6.  The measurement of how much mass is contained in a given volume of an object.  Density=Mass/Volume  Every substance has its own characteristic density.

7.  Scientist use the Celsius scale  0 degrees = the freezing point of water.  100 degrees = boiling point of water.

8.  1. What are 2 benefits of using the International System of Units?  2. What is the basic unit for length? For mass? For volume?