Day 2, Thursday, 27 August, 2015The Metric System

Physics and Science The Metric System Scientific Notation

Day 6, Tuesday, 31 August, 2010Metric System

Physics and Science The Metric System Scientific Notation

What is Physics?

Physics (Greek: φύσις (phúsis), "nature" and φυσικῆ (phusiké), "knowledge of nature") is the branch of science concerned with discovering and characterizing universal laws that govern matter, energy, space, and time.

Limits of science Natural sciences deal only with what is

observable or testable. Science cannot go into matters of faith

Scientists and experiments are flawed. The process (over time) is self correcting.

Difference between Art and Science

Science agrees on some main points (theories). So progress may be judged. Freud turned Psychology into a science.

Art has no point of agreement. There is no way to judge progress. Bach vs Beatles

Major branches of science

Chemistry Physics Biology

Minor branches of science

Places Geology, Oceanography, Meteorology,

Astronomy Relationships

Environmental Science Special interests

Psychology, Anthropology, Sociology, etc.

Metric System

Metric System International System of units (SI) MKS

Meter, Kilogram, Second

CGS Centimeter, gram, second

Metric Units

Units (multiples of ten) Base Derived

Prefixes

Base Units

Length MeterMass KilogramTime SecondAmount MoleTemperature kelvinElectrical current ampereLuminosity Candela

Derived Units

Electrical resistance ohm Frequency hertz Force newton Energy joule Power watt Voltage volt

Scientific Notation

1.234 X 105

3 parts to a number in scientific notation

1. The Coefficient

2. Times 10

3. The Exponent

The Coefficient

This is the actual number (in front) It must have one digit before the

decimal point. So, it is between 1 and 10.

Drop all trailing zeros (unless they were measured and therefore significant).

If the number is negative (less than zero)

Then the coefficient will be negative

-1.23

Times ten

Every number in scientific notation has “times ten” in the middle, written as

X 10

The Exponent

The exponent is the exponent of the “times ten”

11X10

It tells the number of tens columns the decimal has been moved over.

The exponent may be positive, or negative

A positive exponent means the number has zeros behind it and is big (greater than one).

A negative exponent means the number has zeros in front of and is small (a fractional number between zero and one).

Big Numbers

Big numbers have trailing zeroes before the decimal .

123,000,000,000.

Big numbers have positive exponents.

1110

Small Numbers Small numbers (fractional numbers

between zero and one) have leading zeroes after the decimal point.

.0000000000123

Small numbers have negative exponents.-11

10

Adding and Subtracting (poor way)

Put in decimal form Perform the addition or subtraction Convert back to Scientific Notation

The size of the number will be the larger exponent (plus or minus one)

1.23 X 1011

- 4.56 X 107

123,000,000,000.- 45,600,000. 122954400000.

1.229544 X 1011

Adding and Subtracting (better way)

Rewrite to get the same exponent Add or subtract the coefficients

1.23 X 1011

- 4.56 X 107

12,300.00 x 107

- 4.56 x 107

12,295.44 X 107 = 1.229544 X 1011

An interesting insight

When you add or subtract in scientific notation the answer will often have the same exponent as the larger number.

The answer’s exponent will never differ from the larger number exponent by more than 1.

Multiplying and Dividing

Multiply or divide the Coefficients normally

Add exponents when multiplying

Subtract exponents when dividing

Multiplication (2 X 105) (4 X 103) Coefficients 2 X 4 = 8 Exponents 5 + 3 = 8

Answer 8 X 108

Division 2 X 105

4 X 103

Coefficients 2/4 = .5Exponents5-3 = 2

Unformatted answer .5 X 102

Proper answer 5 X 101

Credits