Physical Science Notes

Notes posted here AFTER lecture is given: 

Introduction to course, syllabus, What is Real?

Origins of Science, Ionian Awakening, The Scientific Method

Chapter 1, the scientific method
    pages 2-8 and 20-24
    Discussion on reality

1. Know difference between naturalism (there are natural causes) and supernaturalism (there are causes that we cannot sense or ever really know)
2. Difference between external reality (things that you can sense, measure, that don't disappear when you stop believing in them) and internal reality ( things that are believed without evidence, or that are supernatural and can't be detected by physical means)
3. Know that your senses can fool you (optical illusions) but with careful measuring and a methodical approach, reality CAN be discerned.
4. Measurement and reliance on reproducibility is crucial in science
5. There are no supernatural causes, agents or forces allowed in science
6. Skepticism- the habitual questioning or doubting of claims- reliance on evidence.
7. Scientific method- a process to figure out the natural world
8. Formulate a problem
9. Observe and experiment
10. Interpret results
11. test interpretation
12. repeat over and over
13. Hypothesis- an educated guess that can be tested
14. Theory- an general explanation the encompasses a wide range of observations, and that has been repeatedly verified and tested.
15. The Scientific process- like the Scientific method, but adds in the steps of publication, peer review, and reproducibility of results.
16. Modifications don't invalidate the theory- refinements as new evidence and methods become available are essential to gaining a more accurate picture of reality.
17. The triumph of science lies in it's ability to predict

Keplers laws, historical people, beginnings of modern science

Important people

•         Thales of Miletus

–        First Scientist

–        Predicted eclipses

–        Used geometry to measure pyramids

–        Explained creation of Earth without invoking gods

•         Democritus of Abdura

–        Predicted Atoms

We either study living things (life science)

                        non-living things (physical science)

In either case, the goal is to explore and understand NATURE

Skeptic:

One who instinctively or habitually doubts, questions, or disagrees with assertions or generally accepted conclusions

Scientific Method Steps
From pages 2-3

1)State the problem.

2) Observation and experiment

3)Interpretation

4)Test the interpretation

  + an extra step!....

•         Peer review and Report findings to others so they can repeat the experiment

Observations:  We use our senses to gather information about the world around us.  There are two types of observations.

Qualitative observation:  (quality) Usually made with our senses.

Quantitative observation: (quantity)  How many.  Will always have a number.

•         Key Players:

–        Nicolas Copernicus

–        Claudius Ptolemy

–        Tycho Brahe

–        Johannes Kepler

–        Galileo Galilei

•         Polaris - The North Star

–        Seems to remain stationary as other stars move around this star

–        Used as a guide for travelers due to its constancy

–        Why?

•         If a line is extended outward along the direction of the Earth’s rotational axis, Polaris would lie on the line ( close enough…)

•         Planet motions across the night sky seem to lag behind the stars

–        Difficult to explain

–        “retrograde motion”

Ptolemy's description of the universe included an unmoving Earth at the center:
 “geocentrism”

Copernicus hypothesized that the SUN was the center of the universe
“HELIOCENTRIC” 

Keppler’s THREE laws

#1: “Elliptical Foci”

Each planet moves about the sun in an orbit the shape of an ellipse, with the sun is at one focus.

#2: “Equal Areas"

The straight line joining a planet with the sun sweeps out equal areas in equal amounts of time.

(A Planet travels faster when it is closer to the sun.)

#3: " Planetary Period "

The time taken for one orbit is related to the distance from the sun in a specific way.

Kepler’s work improved upon Copernicus’ theories by modifying the heliocentric system model of our solar system.

Retrograde is an Optical Illusion!

1. The tides are the result of the gravitational interaction of the Sun-Moon and Earth (see pages  21-22)
2. Know difference between and causes of, Neap tides and Spring tides
3. Know that the discovery of planet Neptune was the direct result of the theory of gravity.

Tides

There are Two Tidal Bulges

• Moon's Gravity Pulls Oceans - Near-side Bulge is Easy to Understand
• Moon and Earth actually orbit around the Earth-Moon Center of Mass (about 1500 km beneath the surface of the Earth)
• Motion of Earth Around Center of Mass Creates a Bulge on the Far Side of the Earth

Both Moon and Sun Cause Tides

• Spring Tides
  • New or Full Moon
  • Sun and Moon Pulling in Parallel Directions
  • Lunar and Solar Tides Add Up
  • Unusually Large Tidal Range
• Neap Tides
  • First or Last Quarter
  • Sun and Moon Pulling At Right Angles
  • Lunar and Solar Tides Partially Cancel
  • Unusually Small Tidal Range

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