 There are two focusing knobs on a microscope:  What are they?  Define when to use each.  How do you find the total magnification of the microscope.  What does the diaphragm do on a Microscope?

The Metric System AKA SI or Système International

 When people first started to measure things, the systems were different in different parts of the world.  Many systems were based on parts of the body.  FootInch

 Many countries tried to make a system of measurement.  Both France and England came up with systems that are used today.  England started the English Standard System and France started the Metric System.

 English Standard System  Based on: 2, 3, 4, 8, 16  Generally uses fractions 2 pints in a quart 3 feet in a yard 4 quarts in a gallon 12 inches in a foot 16 ounces in a pound  Metric System  Based on: 10 (like U.S. money)  Generally uses decimals 100 centimeters in a meter 1000 grams in a kilogram 1000 milliliters in a liter

 Over 95% of the world uses the Metric System.  The metric or SI (scientific international) system is aids scientists in sharing measurements  No need to convert another person’s data if we all work in SI  Ex/ NASA still works in imperial units and has had difficulty when needing to work with other groups that use metric ▪ In 1999 the Mars Climate Orbiter was lost because the altitude control system used imperial units and the navigation software used metric.

 Units can be scaled by factors of 10 depending on what you are measuring  So it can be used for small stuff as well as large  king Henry Died by drinking chocolate milk  kilo- Hecto- Deca- Base- deci- centi- milli-  /10 th 1/100 th 1/1000 th  You are only responsible for the units in black

 Measurement: Mass  Unit used: Gram (g)  Tool Used: Balance A paper clip has the mass of about 1 gram.

 Measurement: length/distance  Unit used: Meter (m)  Tool Used: Ruler/meter stick A centimeter is about the width of a small fingernail

A liter is just a little bit more than 1 quart ( or 2 pints )  Measurement: Volume  Unit used: Liter (l)  Tool Used: graduated cylinder

 Measurement: Temperature  Unit used: Celsius (C)  Tool Used: Thermometer  0 o Celsius= freezing  100 o Celsius= boiling

 As of the late 1970s, only the United States, Liberia (Africa) and Myanmar (formerly Burma in Asia) use the English Standard System.  Every other country, and scientists worldwide, use the metric system.

 Convert 15 grams (g) to kilograms (kg)  15 g X 1 kg = kg 1000 g.015

 Metric System Pre-Lab  Due Tomorrow (Thursday)  Study Guide  Due Tuesday Sept 22  Exam Thursday Sept 24

 What are the metric prefixes which we remember with king Henry Died by drinking Chocolate Milk  What percentage of the world’s countries use metric?  When is the first Exam?  When is the Study Guide Due?