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Is the following statement true? “Kepler’s Laws are valid for all planetary systems.”
A) True, Kepler’s Laws are given by the universal law of gravitation which is valid everywhere.
B) False, they are only valid for in the Solar System.
C) True, but only in our Galaxy.
D) False, because Newton’s Laws contradict Kepler’s Laws.
A) True, Kepler’s Laws are given by the universal law of gravitation which is valid everywhere.
First telescopic observations, provide evidence for heliocentric model and disproves Aristotelan “physics”
Galileo Galilei
No measurement is perfect: every measurement has some uncertainty. This is not the same as a “mistake” (wrong measurement). Every measurement or statistic is meaningful only with its uncertainty (although if the uncertainty is very small, it is sometimes not mentioned for simplicity). Repeating measurements usually helps improving the accuracy.
Measurements and Uncertainties
Data and the Scientific Method: In the scientific method, observations (data) are most useful for
A) Testing predictions made by mode.
B) Making prediction.
C) Proving theories.
D) Generating catalogs.
A) Testing predictions made by mode.
B) Making prediction.
C) Proving theories.
D) Generating catalogs.
Specific relation that was verified by great many tests.
Law
Newton explained Kepler's laws
A) As the "music of the spheres".
B) By putting Kepler's complicated formulas into words that could be easily understood.
C) By giving them a sound religious footing.
D) By showing mathematically that the planets move according to a few simple, universal principles of motion and gravity.
A) As the "music of the spheres".
B) By putting Kepler's complicated formulas into words that could be easily understood.
C) By giving them a sound religious footing.
D) By showing mathematically that the planets move according to a few simple, universal principles of motion and gravity.
New level of mathematics: Identifies the physical force behind the planetary orbits (gravity) and provides general mathematical description of the laws of motion
Newton
Seek explanations for observed phenomena that rely solely on natural cause.
Progresses through creation & testing of models of nature that explain the observations as simply as possible.
Make testable predictions about natural phenomena. If predictions for not agree with observations, model must be revised or abandoned.
Science
What is a Scientific Theory?
Very different from everyday theory, which is often just a guess or a speculation. In contrast, a scientific theory is at the highest level of fundamentally important models.
Usually survived several tests, assumed to be possible valid for testing purposes
Working Hypothesis/Model:
Re-proposes the heliocentric system (circular orbits)
Copernicus:
Tools of science is
Logic
Think about: Ptolemaic vs. Copernican model If two models agree equally well with the observations, the simpler of two models is preferred.
The objective search for truth is at the heart of the scientific inquiry. It is not possible to claim absolute certainty because not all possible observations can be made. Anyone that claims the opposite is not precise.
Scientific objectivity and integrity
(usually wrong)
Hypothesis
First extensive, accurate observational database
Tycho Brahe
Science is data-driven, so progress is made by
1) Gathering more data ____!
2) Repeating the experiment _____!
3) Someone else repeating the experiment ____!!!
1) Good!
2) Better!
3) Best!!!
Consider claim: “Aliens are visiting Earth in UFOs. Proponents claim thousands of eyewitness accounts - scientific evidence? Verifiable Eyewitness accounts shown to be very unreliable. Hard evidence that can be studied is required - in decades no actual hard evidence was ever found.
Verifiable Evidence
A powerful, yet simple model that makes predictions that survive repeated and various testing, its status is elevated to theory.
Examples: Newton’s theory of gravity, Einstein’s theory of relativity, Darwin’s theory of evolution.
Working toward a “Theory of Life in the Universe”
Scientific Theory:
(untested, exploratory)
Idea, speculation
Elliptical orbits in a heliocentric solar system; develops correct physical laws to describe planetary orbits
Johannes Kepler
What is Scientific Evidence?
Evidence is anything that is helpful in drawing a conclusion.
- Based on data.
- Reproducible.
- Quantitative.
- Not subjective.
- Never perfect (need to know the limitations!)
Scientific evidence is:
Simple, powerful and general model verified by large number of tests, usually of great importance
Theory:
Often Misused to Mislead People
Scientific Nomenclature