The seven major fields of physics are mechanics, thermodynamics, waves, optics, electromagnetism, relativity, and quantum mechanics. The scientific method involves making observations, defining a problem, developing a hypothesis, testing the hypothesis through experiments, and drawing a conclusion. The difference between accuracy and precision is that accuracy refers to how close a measurement is to the accepted value, while precision refers to the repeatability of measurements and the number of significant figures used. Significant figures are used to express the precision of measurements by determining the number of digits that should be written.

1. 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?

2. 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.

3. Areas of Physics Mechanics Thermodynamics Waves Optics Electromagnetism Relativity Quantum Mechanics

4. Scientific Method Make observations Define the problem (Ask a question). Develop a Hypothesis Test hypothesis with experiments Conclusion – an “interpretation” of experimental results.

5. A Scientific Method

6. A Scientific Method

7. A Scientific Method

8. A Scientific Method

9. A Scientific Method

10. A Scientific Method

11. SI Units Length – 1 meter (m) Mass – 1 kilogram (kg) Time – 1 second (s) Temperature - 1 kelvin (K) Derived Units Combination of units`

12. 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.

13. 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 10 4 1 gram of hydrogen contains 301,000,000,000,000,000,000,000 molecules 3.01 x 10 23 molecules 0.00081 = 8.1 x 10 -4 Decimal moves 4 place to the right 34,000 = 3.4 x 10 4 Decimal move 4 places to the left

14. Powers of Ten Used for very large and very small number Precision expression d deci- 10 -1 E exa- 10 18 c centi- 10 -2 P peta- 10 15 m milli- 10 -3 T tera- 10 12  mico- 10 -6 G giga- 10 9 n nano- 10 -9 M mega- 10 6 p pico- 10 -12 k kilo- 10 3 f femto- 10 -15 da deka- 10 1 a atto- 10 -18 h hecta- 10 2

15. 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

16. 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.

17. 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.