Conceptual Physics Mr Evans Rm 714 Objectives Define physics List the 6 branches of physics Define model Explain the importance of models Describe how models are used

What is this about?! The primary focus of the course is to construct accurate mental models which appropriately depict the behavior of waves, sound, and light, the motion of objects, and the nature of electricity.

Isn’t this just like math?! A wealth of our time is spent making applications of physical principles in order to analyze real-world situations.

But I’m not good with math!! Contrary to popular belief, difficulty in physics can almost always be traced back to conceptual misunderstandings, not mathematical difficulties.

What do you think? Does physics, or any class for that matter describe reality exactly as it is?? 2. Do you think that, collectively, scientists make outrageous assumptions about a situation???

Lesson Objectives At the end of this lesson, you should be able to: 1.Define Physics 2. List the 5 subtopics of physics 3. Give, at least, 1 example of each subtopic.

Science vs. Technology Science is a system of knowledge and the methods you use to find that knowledge. Science begins with curiosity and ends with discovery. The goal of science is to expand knowledge.

Technology is the use of knowledge to solve practical problems. The goal of technology is to apply knowledge.

Science and technology are interdependent Science and technology are interdependent. Advances in one lead to advances in the other. Advances in the study of physics lead to the invention of the transistor. The use of transistors, in turn led to the advances in various other scientific fields, such as computer science and space science.

What is Physics? The goal of physics is to understand the rules that govern the way the natural world behaves.

I. The Nature of Physics and Learning Physics? Physics is a process of learning about the physical world by finding ways to make sense of what we observe and measure. Learning physics requires that you continually compare and contrast your observations to your intuitions and expectations.

Physics helps you make sense of the physical world. Physics is the refinement of common sense. It is more than common sense. Physics is common sense made consistent by continued reference to both theory and experiment. Physics is not a jumble of separate equations to be memorized.

The key to understanding physics is to learn fundamental relationships and to apply them to new scientific problems.

Conclusion… Physics is defined as the study of matter and energy…it is the study of everything.

True/False 1.Temperature is the same thing as heat FALSE Temperature is a measure of the average kinetic energy of molecules. Heat is thermal energy transferred from a hot to a cold region. If heat were the same thing as temperature then adding heat to an object would always increase its temperature. However, it’s possible to add large amounts of heat to an object and not change its temperature at all. For instance, large amounts of heat can be added to a block of ice at its melting point without increasing its temperature, that is until it completely melts.

True/False 6. To produce heat, the sun burns hydrogen in a combustion reaction. FALSE

True/False 8.If a feather and hammer are dropped on the Moon at the same time from the same height they will hit the Moon’s surface at the same time. TRUE

True/False 9. The Moon has no gravity. FALSE 11) False. Mass and weight are distinctly different concepts. Weight is the gravitational attraction force on an object from a nearby planet. Mass in chemistry is the amount of matter present. In physics it’s inertia, or in other words the resistance to changes in motion. Mass does not change when it is placed on a different planet with a different gravity level. Weight, however, does change. An object’s weight can actually be increased with no change in its mass by transporting the object to a planet with a larger gravity level. The tendency to confuse weight and mass frequently comes from science classes. Students are often told that something weighs a certain number of kilograms. In SI units, weights should be in newtons and masses in kilograms.

True/False 10. Mass and weight have essentially the same meaning. To increase the weight of an object requires an increase in the mass of the object. FALSE 11) False. Mass and weight are distinctly different concepts. Weight is the gravitational attraction force on an object from a nearby planet. Mass in chemistry is the amount of matter present. In physics it’s inertia, or in other words the resistance to changes in motion. Mass does not change when it is placed on a different planet with a different gravity level. Weight, however, does change. An object’s weight can actually be increased with no change in its mass by transporting the object to a planet with a larger gravity level. The tendency to confuse weight and mass frequently comes from science classes. Students are often told that something weighs a certain number of kilograms. In SI units, weights should be in newtons and masses in kilograms.

True/False 12. An astronaut orbits the Earth 500 miles above its surface. She appears to be weightless because there is virtually no gravitational force on her. FALSE

True/False If a car hits a tree, the car’s occupants (assume no seat belts or air bags) will be violently thrown forward due to a force created by the car seats. False

True/False 26. Iron can exist as a gas. TRUE

What are the branches of physics?

1.Mechanics -The study of motion and its causes…kinematics and dynamics.

2.Thermodynamics -The study of heat and temperature. Thermo = heat

3. Waves and Optics -the study of specific types of wave motion and light

4.Electromagnetism -The study of electricity and magnetism Remember this by breaking the word apart. electro (electricity) + magnetism = electromagnetism

5. Modern Physics Include the areas of 1.Relativity -The study of high speed particles. 2. Quantum Physics and Atomic Physics - The study of the nature of matter and light at the microscopic level. For wildlife conservation study, this turtle has been fitted with a collar containing a global positioning system (GPS) receiver, allowing the turtle to be tracked over thousands of miles with an accuracy of ≤20 m. An understanding of the theory of relativity can be attributed to the accuracy of a GPS receiver!

What do you think? Which areas of physics deal with the following? Cooling off on a hot day by diving into a swimming pool. Wearing a pair of sunglasses. Building a louder stereo system in your car. Bungee jumping Playing in the high school band Thermodynamics, mechanics optics Vibrations, waves, electromagnetism Mechanics, vibrations and wave phenomena. Vibrations, waves Other answers are possible, take all other reasonable responses.

How is physics distinct from chemistry, biology or other sciences?

Physics does not, nor is it supposed to, describe reality exactly as it is. Part of the art of solving physics problems or analyzing phenomena is choosing the right model.

Lesson Objectives At the end of the lesson you should be able to: Define model as it relates to science. Explain how models are used in science. List 3 types of models also known as representations used in physics. Provide examples of how each representation is used in physics.

Models: A Vehicle for Understanding Understanding Physics begins with building models…mentally, that is! Modeling, in science, is a skill that takes some practice and experience to acquire.

Model Building involves: Simplifying the situation Isolating the essential features of that situation Developing a set of relationships (usually in the form of equations) that provides an adequate, although not perfect, description of reality.

Think/Pair/Share Consider the phrase, “The quick brown fox jumped over the lazy dog.” Which details of this situation would a physicist who is modeling the path of a fox ignore?

What kinds of models will you use in this course? 1. Pictures (pictorial representation)- shows a sketch of the situation. All of these reps provide simplified, yet powerful versions, more complex ideas.

What kinds of models will you use in this course? 2. Graphs (graphical representation)- graphs are very useful for identifying trends and drawing conclusions. All of these reps provide simplified, yet powerful versions, more complex ideas.

What kinds of models will you use in this course? 3. Math (mathematical representation) – demonstrates relationships in very brief terms All of these reps provide simplified, yet powerful versions, more complex ideas.