Honors Physics Introduction
What is Physics? Most Basic of all Science. Attempts to explain nature by understanding The behavior of matter. The structure of matter
The Behavior of Matter 2. Why does the motion of matter change? Why does matter move? Contact Force fields 2. Why does the motion of matter change? change velocity change direction vibrate 3. Why does matter interact with energy? heat up, cool down give off light, absorb light reflect energy transmit energy bend light waves 4. Why does matter interact with matter? collisions 5. Why does matter have charge?
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
If the hypothesis is generally accepted it becomes a THEORY Physics attempts to bring order to our observations by using the scientific method Make an observation. Form a testable hypothesis Test the hypothesis Form a conclusion Hypothesis rejected Hypothesis is modified and retested Hypothesis is accepted Publish the hypothesis for others to test If the hypothesis is generally accepted it becomes a THEORY
example of flawed scientific method
Repositioning of an object from one location to another location Motion Repositioning of an object from one location to another location
Motion Aristotle (384-322 BC) His hypothesis on natural state of an object’s 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
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?
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.
Motion THERFORE this was NOT a reasonable hypothesis 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
Motion THERFORE this was NOT a reasonable hypothesis 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 He should have designed tests to support his hypothesis
Proper Application of Scientific Method
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 the object was exposed to.
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 the object was exposed to. Change in velocity was directly proportional to friction of surface
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 the object was exposed to. Change in velocity was directly proportional to friction of surface Hypothesis: object will move with a constant speed and direction unless interfered with by an unbalanced force
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 the object was exposed to. 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
Motion Found speed varied inversely with friction 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 the object was exposed to. 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 Proper use of scientific method Formed a new era of scientific reasoning
Motion Found speed and direction varied inversely with friction 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 the object was exposed to. 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 Proper use of scientific method Formed a new era of scientific reasoning
2nd Example of Early Proper Application of Scientific Method
Geocentric Universe Earth centered universe Observations all stars, planets and sun appeared to revolve around earth
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
Geocentric Universe More accurate observation should that this hypothesis did not support all observations Retrograde motion of planets Moon like phases of planet Venus
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
Helios-Centered Universe Further observations found this to be flawed
Helios-Centered Universe Further observations found this to be flawed Ultimately lead to current hypothesis of the Big Bang Theory Evidence Red shift
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
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.
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
Theories: Broader more detailed explanation that is provided by quantitative (measurable) and testable prediction. These predictions can often be made with great precision
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
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)
Principle: A less general and more precise statement about a particular phenomena
Principle: A less general and more precise statement about a particular phenomena Examples 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. 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.