Warm - up What is physics?

the natural science which examines basic concepts such as energy, force, and space-time and all that derives from these, such as mass, charge, matter and its motion.

What do you have you done today that involves physics?

1-2: Physics & Measurements Identify the major fields of physics.

Describe the process of the scientific method.

List basic SI Units.

Distinguish between accuracy and precision.

Use significant figures.

Areas of Physics Mechanics

Thermodynamics

Waves

Optics

Electromagnetism

Relativity

Quantum Mechanics

Scientific Method Make observations

Define the problem (Ask a question).

Develop a Hypothesis

Test hypothesis with experiments

Conclusion – an “interpretation” of experimental results.

A Scientific Method

A Scientific Method

A Scientific Method

A Scientific Method

A Scientific Method

A Scientific Method

SI Units Length – 1 meter (m)

Mass – 1 kilogram (kg)

Time – 1 second (s)

Temperature - 1 kelvin (K)

Derived Units Combination of units`

Accuracy Vs. Precision• Accuracy• How close your

measurement is to an accepted value for that measurement.

• Depends on how carefully the measurement was made.

• Precision-2 Meanings• The repeatability of a

measurement.• The number of

significant digits in the measurement.

Depends on the equipment used.

Scientific Notation A number written as a product of two numbers: a

coefficient and a power of 10

Designed for the expression of very big and very small numbers 3.6 x 104

1 gram of hydrogen contains 301,000,000,000,000,000,000,000 molecules

3.01 x 1023 molecules

0.00081 = 8.1 x 10-4

Decimal moves 4 place to the right

34,000 = 3.4 x 104

Decimal move 4 places to the left

Powers of Ten Used for very large and very small number

Precision expression

ddeci-10-1 Eexa-1018

ccenti-10-2 Ppeta-1015

mmilli-10-3 Ttera-1012

µmico-10-6 Ggiga-109

nnano-10-9 Mmega-106

ppico-10-12 kkilo-103

ffemto-10-15

dadeka-101aatto-10-18

hhecta-102

Significant Figures A method of expressing error in measurement.

Measure a value and then estimate one degree below the limit of the reading .

5.35 cm

Significant Figures Atlantic – Pacific Rule

Pacific – "P" is for decimal point is present. If a decimal point is present, count significant digits starting with the first non-zero digit from the left. 0.004703 has 4 significant digits. 18.00 also has 4 significant digits.

Atlantic – "A" is for decimal point is absent. If there is no decimal point, start counting significant digits with the first non-zero digit from the right. 140,000 has 2 significant digits. 20060 has 4 significant digits.

Summary What are the seven areas of physics?

Mechanics, Thermodynamics, Waves, Optics, Electromagnetism, Relativity, Quantum Mechanics

What is the difference between accuracy and precision? Accuracy is measuring the accepted value. Precision is repeating very similar measurements.

What is the purpose of Significant figures? To express precision. Determine the number of digits to write.