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Physics
Introduction
1
What is Physics?
• Most Basic of all Science.
2
What is Physics?
1) Attempts to describe the organization of
the immediate environment
the world
the universe
This includes all matter and energy
3
What is Physics?
2) Attempts to understand the natural laws that
govern the world and the universe
4
What is Physics?
3) Offer processes that identify, understand, and
apply these natural laws
5
Learning Physics
• Physics is learned by
6
Learning Physics
• Physics is learned by
• Observing
7
Learning Physics
• Physics is learned by
• Observing
• Asking questions (inquiry)
8
Learning Physics
• Physics is learned by
• Observing
• Asking questions (inquiry)
• Forming hypothesis that might answer these
questions
9
Learning Physics
• Physics is learned by
• Observing
• Asking questions (inquiry)
• Forming hypothesis that might answer these
questions
• Performing experiments to prove or disprove
the experiments
10
Learning Physics
• Physics is learned by
• Observing
• Asking questions (inquiry)
• Forming hypothesis that might answer these
questions
• Performing experiments to prove or disprove
the experiments
• Publish your findings and your experimental
results
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Learning Physics
• Release a ball from your hand
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Learning Physics
• Release a ball from your hand
1) Observation
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Learning Physics
• Release a ball from your hand
1) Observation
2) Question ( Inquiry)
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Learning Physics
• Release a ball from your hand
1) Observation
2) Question (Inquiry)
3) Hypothesis
15
Learning Physics
• Release a ball from your hand
1) Observation
2) Question (Inquiry)
3) Hypothesis
4) Experimental evidence to support hypothesis
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Learning Physics
• Release a ball from your hand
1) Observation
2) Question (Inquiry)
3) Hypothesis
4) Experimental evidence to support hypothesis
5) Publish your results
17
Learning Physics
• Ask a question
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Learning Physics
• Ask a question
• Why does it take more force to move heavier objects?
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Matter
What is matter?
20
Matter
What is matter?
Something that has mass
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Matter
1.
2.
3.
4.
5.
Why does the motion of matter change?
Why does matter move?
How does matter interact with energy?
How does matter interact with matter?
Why does matter have charge?
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Matter
1. Why does the motion of matter change?
 Contact force
 Force fields
2. Why does matter move?
 Contact force
 Force fields
3. How does matter interact with energy?
4. How does matter interact with matter?
5. Why does matter have charge?
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Matter
1. Why does the motion of matter change?


Contact force
Force fields
2. Why does matter move?


Contact force
Force fields
3. How does matter interact with energy?





heat up, cool down
give off light, absorb light
reflect energy
transmit energy
bend light waves
4. How does matter interact with matter?
5. Why does matter have charge?
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Matter
1. Why does the motion of matter change?
 Contact force
 Force fields
2. Why does matter move?
 Contact force
 Force fields
3. How does matter interact with energy?
 heat up, cool down
 give off light, absorb light
 reflect energy
 transmit energy
 bend light waves
4. How does matter interact with matter?
 collisions
5. Why does matter have charge?
 Imbalance between the number of electrons and protons
25
Matter
1. Why does the motion of matter change?
 Contact force
 Force fields
2. Why does matter move?
 Contact force
 Force fields
3. How does matter interact with energy?
 heat up, cool down
 give off light, absorb light
 reflect energy
 transmit energy
 bend light waves
4. How does matter interact with matter?
 collisions
5. Why does matter have charge?
26
Matter
1. Why does the motion of matter change?


Contact force
Force fields
2. Why does matter move?


Contact force
Force fields
3. How does matter interact with energy?





heat up, cool down
give off light, absorb light
reflect energy
transmit energy
bend light waves
4. How does matter interact with matter?

collisions
5. Why does matter have charge?
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The Structure of Matter
• mass
 Why does mass of an object vary with:
 size
• density
 relative density
 buoyancy
• charge
 positive
 negative
 neutral
• atomic structure
 nucleus
 electrons
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Physics attempts to bring order to our
observations by using the scientific method
1.
2.
3.
4.
Make an observation.
Form a testable hypothesis
Test the hypothesis
Form a conclusion
•
•
•
Hypothesis rejected
Hypothesis is modified and retested
Hypothesis is accepted
5. Publish the hypothesis for others to test
If the hypothesis is generally accepted it becomes a THEORY
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example of flawed scientific method
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Motion
Repositioning of an object from one
location to another location
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Motion
Aristotle (384-322 BC)
His hypothesis on natural state of an objects motion on earth
Observation:
Never observed an object in motion on earth that did not eventually slow and stop
Hypothesis
• Natural state of motion for an object on earth was to be at rest
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Motion
Aristotle (384-322 BC)
His hypothesis on natural state of an objects motion on earth
Observation:
Never observed an object in motion on earth that did not eventually slow and stop
Hypothesis
• Natural state of motion for an object on earth was to be at rest
Was this a reasonable hypothesis?
33
Motion
Aristotle (384-322 BC)
His hypothesis on natural state of an objects motion on earth
Observation:
Never observed an object in motion on earth that did not eventually slow and stop
Hypothesis
• Natural state of motion for an object on earth was to be at rest
Was this a reasonable hypothesis?
Maybe, but he never tested his hypothesis.
34
Motion
Repositioning of an object from one location to another location
Aristotle (384-322 BC)
His hypothesis on natural state of an objects motion on earth
Observation:
Never observed an object in motion on earth that did not
eventually slow and stop
Hypothesis
•
Natural state of motion for an object on earth was to be at rest
Was this a reasonable hypothesis?
Maybe, but he never tested his hypothesis.
• THERFORE this was NOT a reasonable hypothesis
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Proper Application of Scientific Method
36
Motion
Galileo (1664-1642 AD)
His hypothesis on natural state of an object’s motion on earth
Observation: objects changed velocity at different rates depending on friction
Hypothesis: object will move with a constant speed and direction unless
interfered with by an unbalanced force
37
Motion
Galileo (1664-1642 AD)
His hypothesis on natural state of an objects motion on earth
Observation: objects changed speed at different rates depending on friction
Hypothesis: object will move with a constant speed and direction unless
interfered with by an unbalanced force
Tested his hypothesis by rolling marbles along surfaces
of varying friction
38
Motion
Galileo (1664-1642 AD)
His hypothesis on natural state of an objects motion on earth
Observation: objects changed speed at different rates depending on friction
Hypothesis: object will move with a constant speed and direction unless
interfered with by an unbalanced force
Tested his hypothesis by rolling marbles along low
friction surfaces
Found speed varied inversely with friction
39
Motion
Galileo (1664-1642 AD)
His hypothesis on natural state of an objects motion on earth
Observation: objects changed speed at different rates depending on friction
Hypothesis: object will move with a constant speed and direction unless
interfered with by an unbalanced force
Tested his hypothesis by rolling marbles along low friction
surfaces
Found speed and direction varied inversely with friction
This lead directly to Isaac Newton’s 1st Law of Motion
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2nd Example of Early
Proper Application of Scientific Method
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Geocentric Universe
Earth centered universe
Observations
all stars, planets and sun appeared to revolve
around earth
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Geocentric Universe
Earth centered universe
Observations
all stars, planets and sun appeared to revolve
around earth
More accurate observations showed that this
hypothesis did not support all observations
43
Geocentric Universe
More accurate observation should that this
hypothesis did not support all observations
• Retrograde motion of planets
• Moon like phases of planet Venus
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Geocentric Universe
More accurate observation should that this
hypothesis did not support all observations
• Retrograde motion of planets
• Moon like phases of planet Venus
• This gave rise to helios-centered universe
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Helios-Centered Universe
• Further observations found this to be flawed
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Helios-Centered Universe
• Further observations found this to be flawed
• Ultimately lead to current hypothesis of the
Big Bang Theory
–Evidence
»Red shift
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Other Ideas and Observations that
lead to scientific discoveries
1. Biology: twitching frog leg that introduced
role of potential difference (voltage) in muscle
contraction
2. Leonardo da Vinci: imagined and formulated
the forces involved in the Roman arch
3. Interaction of nuclear forces inside of an atom
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Models, Theories, & Laws
• model
Is an imagined explanation of a phenomena. It is
often a comparison to something we are familiar
with.
Gives an approximate mental picture of what we can
not see actually happening.
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Models, Theories, & Laws
• model
Is an imagined explanation of a phenomena. It is
often a comparison to something we are familiar
with.
Gives an approximate mental picture of what we can
not see actually happening.
Example: light waves,
can make many comparisons to water waves
50
Models, Theories, & Laws
• model
Is an imagined explanation of a phenomena. It is
often a comparison to something we are familiar
with.
Gives an approximate mental picture of what we can
not see actually happening.
Example: electron shells of an atom
compared to planets orbiting a star
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• Theories:
– Broader more detailed explanation that is provided by
quantitative (measurable) and testable prediction. These
predictions can often be made with great precision
52
• Theories:
– Broader more detailed explanation that is provided by
quantitative (measurable) and testable prediction. These
predictions can often be made with great precision
• Example: Atomic Theory
53
Law :
– A concise (short) but general statement about the
behavior of nature. It can never be contradicted
• Examples:
1. Energy is always conserved
2. Acceleration of an object is directly proportional to the
Net Force applied and inversely proportional to the mass
of the object. (a = F/m)
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• Principle:
– A less general and more precise statement about a
particular phenomena
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• Principle:
– A less general and more precise statement about a
particular phenomena
– Examples
1. Archimedes Principle The buoyant force acting on an
object placed in a fluid will be equal to the weight of
the fluid displaced by the object.
2. Bernoulli's Principle The faster a fluid passes over a
surface of an object, the less pressure the fluid will
apply to the surface of that object.
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