Relationship between Data Science and Physics in the Search for Universal Laws

1. DATA

2. SCIENCE is… the search for relationships that explain and predict the behavior of the universe.

3. PHYSICS is… the science concerned with relationships between matter, energy, and its transformations.

4. There is no such thing as absolute certainty of a scientific claim. • The validity of a scientific conclusion is always limited by: • the experiment • design, equipment, etc... • the experimenter • human error, interpretation, etc... • our limited knowledge • ignorance, future discoveries, etc...

5. Scientific Law a statement describing a natural event Scientific Theory an experimentally confirmed explanation for a natural event Scientific Hypothesis an educated guess (experimentally untested)

6. developed in France in 1795 a.k.a. “SI”-International System of Units • The U.S. was (and still is) reluctant to “go metric.” • very costly to change • perception of “Communist” system • natural resistance to change • American pride

7. The SI unit of: • length is the meter, m • time is the second, s • mass is the kilogram, kg. • electric charge is the Coulomb, C • temperature is the degree Kelvin, K • an amount of a substance is the mole, mol • luminous intensity is the candle, cd

8. The second is defined in terms of • atomic vibrations of Cesium-133 atoms. • The meter is defined in terms of the speed of light. • The kilogram is still defined by • an official physical standard. “Derived units” are combinations of these “fundamental units” Examples include speed in m/s, area in m2, force in kg.m/s2, acceleration in m/s2, volume in m3, energy in kg.m2/s2

9. 1018exa E 1015peta P 1012tera T 109giga G 106mega M 103kilo k 102hecto h 101deka da 10-18atto a 10-15femto f 10-12pico p 10-9nano n 10-6microm 10-3 milli m 10-2centi c 10-1deci d

10. Explore the metric system at link1, link2, and link3. See definitions of metric units here. Click here to do conversions.

11. All measurements have some degree of uncertainty. Precision single measurement - exactness, definiteness group of measurements - agreement, closeness together Accuracy closeness to the accepted value accepted - observed accepted % error = x 100%

12. Example of the differences between precision and accuracy for a set of measurements: Four student lab groups performed data collection activities in order to determine the resistance of some unknown resistor (you will do this later in the course). Data from 5 trials are displayed below. Suppose the accepted value for the resistance is 500 Ω. Then we would classify each groups’ trials as: Group 1: neither precise nor accurate Group 2: precise, but not accurate Group 3: accurate, but not precise Group 4: both precise and accurate

13. 1.All non-zero digitsare significant. 2.Zeros between other significant digitsare significant. 3.Leading zerosare not significant. 4.Final zeros before the decimal are not significant.

14. Operations with Significant Digits Addition and Subtraction (link) round the sum or difference to the least precise decimal place Multiplication and Division (link) round so that the product or quotient has a total number of significant digits equal to the total number of significant digits of the least precise quantity

15. Learn more about significant digits here and here. Check your understanding here and here. The “bottom line” is that the precision to which a measured or calculated amount is written provides valuable information as to the precision (certainty) of that value and the device used to measure it.