Metric System

History and Basics of Metric System

How to use the metric system

Metric Mistakes

Showme Metric Basics

Scale and Materials Science -Nano

Metric System

Advantages

• Well accepted around world.

• Easy to convert within system.

• Convenient for almost any size scale (with prefixes).

Almost all scientific work is reported in metric units because these are so well accepted worldwide. This makes experiments much easier.

Metric Problems

Disadvantages

• NOT well accepted in U.S.A. but very applicable in most countries

• Conversion between any two different systems difficult.

9 Metric Prefixes

10 Orders of Magnitude

Metric system based on powers of 10.

(Classroom display of orders of magnitude).

Conversion between units simply means moving decimal point.

Ex.

1,560,000 m = 156 cm = 1.56 m = 0.00156 km

Note: It takes fewer big units than small units.

11 Metric Conversions

To convert between metric units:

1. Find order-of-magnitude difference between prefixes.

2. This difference indicates how much to shift decimal point.

3. When going from smaller to larger units, make number smaller.

4. When going from larger to smaller units, make number larger.

12 Scientific Notation

Convenient for very large or very small numbers.

Ex. 1 gram of water contains

33,400,000,000,000,000,000,000 molecules

or

3.34 x 10^22 molecules

Sci. Notation Explained

In scientific notation,

number x 10exponent

number- must be \geqslant 1 and < 10 exponent – indicates position of decimal point Positive (+) exponents indicate large numbers (>1)

Negative (-) exponents indicate small numbers