What is a Physicist?

1. What is a Physicist? • Visualize a physicist • “Paint” a picture

2. Names in Physics? • Newton • Einstein • Pascal • Faraday • Fermi • Shockley • Aristotle • Archimedes • Hawking • Tesla • Hubble • Feynman • Henry • Hertz … only a selection!

3. What is the Goal of Physics? • To use a small number of basic concepts, equations and assumptions to describe the physical world. • Physics is the study of the laws of nature, because physics is everywhere!

4. Areas within Physics • Mechanics • motion, forces • Thermodynamics • heat & temperature • Vibrations and wave phenomena • Optics • light, mirrors • Electromagnetism • electricity & magnetism • Relativity • particle motion • Quantum mechanics • behavior of submicroscopic particles

5. Make observations and collect data that lead to a question Formulate and objectively test hypotheses by experiments Interpret results and revise hypothesis if necessary State conclusions in a form that can be evaluated by others – develop a theory! Scientific Method – basis of scientific investigation

6. Measurement in Physics • Systems of units • (SI) Metric MKS • Meter (M) • Kilogram (K) • Second (S) • English FPS • Foot (F) • Pound (P) • Second (S)

7. Common Conversion Values • 1 meter = 39.37” • 1 inch = 2.54 cm = 0.254 meters • 1 mile = 1609 meters • 1 kilogram = 2.2 lbs • 1 oz = 28 grams • 60 mph = 28 meters/sec • km/h > m/s = 1609/3600 = x 0.45

8. Common Prefixes • Pico (p) 10-12 • Nano (n) 10-9 < • Micro () 10-6 < • Milli (m) 10-3 < • Centi (c) 10-2 < • Kilo (k) 103 < • Mega (M) 106 < • Giga (G) 109 • Tera (T) 1012

9. Scientific Notation • A number in (pure) scientific notation is of the form • a * 10n, where • 1 < a < 10, • n = an integer • Ex. 3.4 * 107, 9.1 * 10-4 • Scientific Notation on Your Calculator • Most calculators now have a key on them for doing scientific notation. Look for one of the following... • EXP (most Casio calculators) • EE (most TI calculators, and you might have to use the 2nd function key to use it) • Sometimes expressed in convenient terms!

10. Minimum Measurement • Whatever the scale (units) on a measuring device, the error you should record is one half of the smallest division. • Often this is stated as the "possible error" in the measurement. • Example 4: If you measure the length of a pencil using a regular ruler (they usually have 1 mm divisions) and find that it is 102 mm long, you should write down… • Length = 102 ± 0.5 mm Stop here

11. Steps in Problem Solving • List the given data (Given) • List what has to be found (Find) • Draw and label a diagram, if possible • Which principles & equations are relevant to the problem – how are they used? • Simplify the equations and solve the unknowns in algebraic form • Check for unit consistency and convert if needed • Insert numerical values and calculate the result, observing significant figures and calculator requirements – use parentheses if in doubt! • Check your answer – does it make sense?

12. Guesstimation! • Basic skill for finding “ballpark” answer • Example • Roughly, how many cans of soda are consumed by Stauntonians – population 25,000 – in a year? • Assumptions: • ½ of population drink soda 4 times a week • Calculations • 25,000 x ½ x 4 x 52 = 2.6 million cans!

13. Summarize Critical Thinking • Given: • what do I know? • Find: • what are the unknowns? • Tools: • What concepts (therefore equations) can be used to solve the problem? • Solve: • Use the tools to solve the problem • Check: • Does the answer make sense?

14. Graph Relationships • Linear: y = mx + b

15. Graph Relationships • Quadratic: y = ax2

16. Graph Relationships • Inverse: y=1/x