Table of Contents
1. UnitsPhysics goal: Work with units in equations, convert from one sort of units to another, and be able to check your answers or even figure out how to solve an unexpected problem based on what units and equations you already know.
Math goal: Symbolic manipulation - be comfortable doing algebra even when you have to work with variables rather than numbers.
Why you should care: Math is a language. When you take a language like Latin or Spanish, you learn how to converse in that language and how to translate in and out of that language. Math, on the other hand, has probably always been taught to you as somethign entirely abstract. Physics is different - it uses the language of mathematics to describe reality, and to allow us to predict how the world works.
In the end, the reason this should matter to you is that mathematics is power. I'm not really talking about social or economic power, although it's true that in our society math is the gatekeeper that locks many people out of high-paying jobs. Rather, understanding mathematics gives you power over numbers. Nearly everything in life can be seen as a number, and if you are good at math, it means that you can take any set of numbers and manipulate them to find the result you need.
2. Linear MotionPhysics goal: Rate of change, both calculated numerically and as the slope of a graph. Rate of change is a measure of how much one variable changes when another changes.
Math goal: Reading graphs - by looking at a graph, be able to determine the value of one variable for any given value of the other, be able to describe how one variable changes as the other changes, and find the slope at any point.
Why you should care: The linear motion equations are the simplest way to describe the motion of an object. Phrases like "speed up," "slow down," and so on are really based on ideas in physics, so to really understand how, for example, a car moves, you need to know the physics behind it.
Reading graphs is an essential skill in life. You have to be able to pick out individual data points and identify trends in order to track the performance of a company (say, before accepting a job there or buying stock). Graphs can also help you to organize information and notice trends and patterns.
Rate of change is the most important single idea in physics, so important that the founder of physics, Isaac Newton, developed an entirely new type of math (Calculus) just to deal with it. All the quantities that we will deal with in this first part of physics are related either by some conversion using their mass, or by a rate of change relation.
Linear Motion (10/20/05)
3. VectorsPhysics goal: Two dimensional motion: At the start of linear motion, we said that we were purposefully simplifying the world by assuming that everything moves in a line. Now, we want to take into account the fact that most objects move in two or more dimensions at once.
Math goal: Vectors: A vector is how, in math, we represent some measurement that goes in more than one direction at once. In this unit, you will learn how to add, subtract, and scale vectors, and how to use these simple procedures to solve problems.
Why you should care: Two dimensional motion is what is used to describe the motion of a space ship slinging around the moon, or of a trebuchet's boulder flying through the air. Once you have learned how to deal with vector motion, you will be able to figure out things like what angle a baseball should best be hit at.
Vectors are another really big idea in math that you will be introduced to in physics. We will be using them for the rest of the class, expecially in the next unit, Force. It is possible you won't see them anywhere else in high school unless you take AP physics, but when you get off into college or the real world you will find them everywhere (They are particularly useful in computer games, which are Mr. Z.'s other passion).
4. ForcePhysics goal: Force and force diagrams. As we progress toward our goal of understanding "the causes of things," we will move away from simply describing motion and change in motion, and try to understand why things move, and why their motion changes. The simplest way to answer this question is that once an object is moving, it will keep moving, but in order to change its motion, I need to give it a push, exert a force on it.
Math goal: Trigonometry. There are many forces acting on any object, from many different directions. In order to find the vector form of a force at an angle, we need to be able to find the components given the angle. For this, we use trigonometry, the math functions that convert from angles to lengths.
Why you should care: One thing force diagrams are often used for is in research into sports such as hockey and figure skating, basketball, football, or auto racing. A trainer with a good understanding of how force works can teach someone how to jump higher, how to block better, or how to take a car around a turn while maintaining as much speed as possible.
Trigonometry is an indispensable tool in engineering and science, because it is very common to need to convert something from an angle into a length and vice versa. I remember being very frustrated in eight grade math because I could tell that something like the trigonometric functions ought to exist, and that if they did, it would open up a whole new world of possibilities in geometry, but I wan't able to figure out, using eigth grade math, how to calculate the trig functions. Once you know the trig functions, you can solve almost any problem that involves angles and measurements.
5. EnergyPhysics goal: Energy conservation and work. In physics, energy is a measurement of how dangerous something is, of how much it is able to do. Energy is useful to us in solving problems because it is conserved: the total amount of energy in a situation never changes, although energy can change its form (heat, motion, and height each give an object a particular type of energy) or be transfered from object to object.
Math goal: Reading graphs. In addition to all the skills from the linear motion unit (reading a graph, finding slope, finding area) you need to know how to look at several "stacked" graphs and identify what part belongs to what quantity.
Why you should care: This is probably your first formal introduction to the idea of conservation, an idea that, along with the related idea of symmetry, is one of the foundations of physics. Energy is used commonly in designing cars and other vehicles, such as roller coaster cars.
The graphical skills you will use in this chapter are the same that are used when planning out a budget, determining the result of a chemical reaction, or tracking the population of a school district. If you get into any sort of business as a career, you will need to be comfortable looking at a graph and understanding what information it conveys.
6. Field ForcesPhysics goal: Gravity and electrical attraction are field forces forces that act over a distance without requiring any contact between two objects. They both act in very similar ways.
Math goal: Number sense. In order to deal with field forces, you need to be able to work with very big and very small numbers. Our goal in this chapter is to have you be comfortable working with different ways of expressing a number (fraction, decimal, scientific notation) and to have some sort of feeling for the size of a number when you look at it.
Why you should care: Many of you have complained to me that you feel uncomfortable working with fractions, decimals, and percents. Understanding numbers in various forms just happens to be something that you, as a modern human being, have to know; so, we're taking some time to review it here.
If you're one of those people to whom numbers make no sense, take heart. If you're willing to try to follow along, you'll find that understanding numbers is not as hard as you've always thought. If your teachers in earlier years had taken some time out to get you caught up, you wouldn't have had to go halfway through high school feeling like math was too hard for you.
7. ElectrostaticsPhysics goal: Electrostatics - the behavior of charge and charged objects. When you get a shock from a metal doorknob on a dry day or you rub a balloon against your hair and it sticks there, you are experiencing electrostatics. You will learn to understand how these phenomena come about through the motion and interaction of the tiny particles that make up matter.
Math goal: One of the fun parts of this chapter is that there is hardly any math involved at all, in the traditional sense of number and mathematical operations. However, it does teach an important skill: being able to think about two things, like the charges in an object, being either balanced, or having an excess one way or the other.
Why you should care: Electrostatics, and the interaction of protons and electrons, are the basis for chemistry, electrical engineering, and several other fields. Being able to think of matter as made up of a careful balance of positive and negative electrical charges, and being able to understand what makes those charges behave as they do, gives you a much better idea of how the world is put together.
8. Electrical CircuitsPhysics goal: Electrical power is all around you. Anything that runs on batteries or plugs into a wall is some sort of electrical circuit. This unit will help you to understand how those circuits work.
Math goal: Solving systems of linear equations. Often a math problem does not start out all nicely put together in a single, solvable equation with a single variable. If you understand how to use substitution, you can write as equations the things that you know, and then follow a math process to get an answer.
Why you should care: At the very least, coming out of this unit you'll be less likely to electrocute yourself or short-circuit a battery. You will also probably have teh tools that you need to do some basic repairs on electrical appliances. Nearly all the tools you depend on are electrical in nature; it's a good idea to understand how they work.
9. HeatPhysics goal: Heat is a type of energy, really just kinetic energy spread out over all the atoms in an object. Because it is a form of energy, we know some things about how it should behave: for example, that heat can be transferred from object to object, or transformed into other forms of energy, but the total amount of energy stays the same. In the chapter, we will study how the idea of heat as energy relates to the more familiar idea of temperature as a measure of heat.
Math goal: Reading exponential graphs. When heat transfers between objects, their temperatures want to match. How quickly the temperature changes has to do with how insulated the objects are and how different their temperatures are.
Why you should care: This is probably the most practical unit in our whole physics course. Heat is something that you encounter all the time in your life: trying to keep warm in winter and cool in summer, cooking food, trying to avoid getting stuck to a cold object or burned by a hot one.
10. OscillationPhysics goal: To oscillate means to move back and forth repeatedly. Oscillation, and the related idea of stability, are central to physics. We will study why oscillation happens, and what determines how fast something oscillates. This will lead into our study of waves, sound, and light.
Math goal: Again, we will be focusing on symbolic manipulation. This time, the goal is to be able to take information, put it into an equation, and then rearrange that equation so that it is in a particular form, all using variables instead of numbers.
Why you should care: Resonance and harmonic oscillation are ideas you use all the time, whether you realize it or not. Swinging on a swing is an exercise in both. Symbolic manipulation, too, is a skill you really need; one of the things that most distinguishes college level math, science, and engineering classes from high school classes is that instead of being given an equation and being asked to plug in numbers, you are asked to derive the equation, and not even bother with numbers.
11. Sound and WavesPhysics goal: Sound and light are both waves similar to those you see in the ocean. In this chapter you will learn how sound is produced and how it travels.
Math goal: This chapter deals a lot with ratios and fractions. You will learn that rational numbers are the basic of harmony in music, and you will learn how to recognize what fraction of a wave will fit into a given string or pipe.
Why you should care: The rules that you learn in this chapter are what is behind all musical instruments, including things like voice and drums. You will be able to understand these instruments in enough detail that you could make a stringed instrument like a guitar or a wind instrument like a pan pipes or a recorder.
Sound and Waves
12. Electromagnetic RadiationPhysics goal: Light is an electromagnetic wave, meaning that it is a waves passed along by oscillations in electrical and magnetic fields. Visible light is just a tiny slice of the electromagnetic spectrum, the whole range of different types of light that are possible. So, for example, the ultraviolet light that causes sunburn is light that is more blue than violet; the infrared light that is produced by heat is light that is more red than red. You are probably familiar with some other types of light such as radio waves, x-rays.
Math goal: Scientific notation: yes, it's back, and you'll be stuck with it for the rest of your life, so we're going to make absolutely sure that everyone understands it. We will also do some fun stuff with geometric optics, which, although the name makes it sound like math, involves no calculation at all - it's just a way to figure out how some mirrors and lenses magnify things.
Why you should care: Every part of the electromagnetic spectrum is useful to us as modern human beings. This unit will help you to understand what things like ultraviolet light are and how we use them. What you learn about electron energy levels will also be important to you in chemistry.
13. MomentumPhysics goal: Momentum is a measurement of the motion of an object that describes how hard it is to stop that object. So, a train has more momentum than a baseball, if both are going at the same speed. Momentum is useful when dealing with collisions: if two objects collide, each one brings a certain amount of momentum into the collision, and this is what determines how the objects move after the collision.
Math goal: Vectors: We will be dealing again with objects that are moving in two dimensions, so we need to review what we know about multiplying and adding vectors and resolving their components.
Why you should care: First of all, this unit is a great review of what we've done at the start of the year, because momentum fits in nicely with all the other units like force, energy, and velocity that we studied. Secondly, it's useful to be able to envision how collisions take place: people who play games like football or pool need to think about collision physics all the time.
14. Final ReviewFinal Notes