+ THE MAGIC OF PHYSICS +
“Any sufficiently advanced technology is indistinguishable from magic”
-Arthur C Clarke
JANUARY 10 th
What is science?
- It deals with observing and understanding the natural world.
- We develop theories based on observations.
- We explain how and why things happen and predict what will happen next.
- The scientific process attempts to answer why does it happen?
Why learn/do science?
- To gain an expanded awareness of the universe
- To address the problems of modern society and their solutions.
- To understand everyday technology.
Physics: The study of universal phenomenon.
The Scientific Process
- Science is based on direct experience and rational thought.
- Experience: observations, quantitative measurements
- Theory: Well confirmed set of ideas that explains what we observe.
- Model: visualization of a theory.
- Hypothesis: reasonable, but unconfirmed idea. (becomes theory when confirmed)
Theory has predictive power, but theories are not absolutely certain.
Science and Pseudoscience:
- Science: A set of methods designed to describe and interpret observed and inferred
phenomena, past or present, aimed aimed at building a testable body of knowledge
open to rejection or confirmation
- Pseudoscience: Claims presented so that that they appear scientific even though
they lack supporting evidence. Aristotle
- Defined “natural philosophy” – a branch of philosophy examining the natural
- First to devise methods for understanding the world based on detailed observation
and cataloging of phenomenon
- Developed earliest theories of motion.
Aristotelian Physics: A Common Sense view
- Natural motion: fall objects, rising air and flames
- Violent motion: needing a constant push or pull to continue
- Celestial motion: motion of the moon, planets, sun and stars.
JANUARY 12 th
Galileo’s Thought Experiment
- Throw a ball across the room.
- Once it leaves my hand, what keeps it moving?
- Aristotle says there must be a constant force to keep it in motion
- Galileo: let a ball roll down an incline; it will speed up. Let it roll up the incline; it
will slow down. Let it roll up the incline; it will slow down. In between on a perfectly
flat surface with no friction, the ball will keep rolling at a constant speed forever.
Rolls down – speeds up Push upwards slows, stops, rolls down
If the plane has no friction, it would roll forever.
The steeper the incline, the faster or slower the object goes.
- experimentation to test hypotheses
- idealization to eliminate side effect
- consider 1 question at a time
- quantitative methods – precise measurements. The Law of Inertia
- Descartes imagined turning off air resistance, friction and gravity.