Warm up 9/16There 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?

How Do Scientists Measure?

The Metric SystemAKA SI or Système International

Way Back When . . .

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.

Foot Inch

How to Measure?

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.

Comparing the two Systems . . . 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 gallon12 inches in a foot

16 ounces in a pound

Metric SystemBased on: 10

(like U.S. money)

Generally uses decimals

100 centimeters in a meter 1000 grams in a kilogram1000 milliliters in a liter

Why the Metric System?

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.

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-

1000 100 10 1 1/10th 1/100th 1/1000th

You are only responsible for the units in black

Mass

Measurement: Mass Unit used: Gram (g) Tool Used: Balance

A paper clip has the mass of about 1 gram.

Length/Distance Measurement: length/distance Unit used: Meter (m) Tool Used: Ruler/meter stick

A centimeter is about the width of a small fingernail

Volume

A liter is just a little bit

more than 1 quart (or 2 pints)

Measurement: Volume

Unit used: Liter (l) Tool Used:

graduated cylinder

Temperature

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

Today . . .

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.

Practice Problems

Convert 15 grams (g) to kilograms (kg)

15 g X 1 kg = kg 1000 g

.015

Classwork Homework

Metric System Pre-Lab Due Tomorrow (Thursday)

Study Guide Due Tuesday Sept 22 Exam Thursday Sept 24

Warm up 9/7

What are the metric prefixes which we remember withking 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?