SECTION 1

Chapter 1The science of physics

Objectives

Students will be able to :Identify activities and fields that involve the

major areas within physics.Describe the processes of the scientific

method.Describe the role models and diagram in

physics.

What is Physics ?

What do you think physics is?Can some one give me some examples of

physics

What is physics?

Physics come from the Latin word physica, which means “study of nature”.

It is the branch of science concerned with property of matter and energy and the relationships between them. It is based on mathematics and traditionally includes mechanics, optics, electricity and magnetism, acoustics and heat.

The goal of Physics

The goal of physics is to use a small number of basic concepts ,equations and assumptions to describe the physical world.

Areas within Physics

Any problem that deals with temperature, size , motion, position, shape, or color involves physics.

Physics categor1ize the topics they study in different ways.

Some of the areas are:1. Mechanics2. Thermodynamics3. Vibrations4. Optics5. Electromagnetism6. Relativity 7. Quantum mechanics

Scientific Method

The scientific method is a body of techniques use to investigate a phenomena, get new knowledge, correct or test theories.

Here are the steps of the scientific method:1. Make observations that lead to a question2. Formulate and objectively test hypothesis 3. interpret results4. state conclusions

Scientific Method steps

Scientific method

Lets look at how the scientific method workLet’s look at the lemonade experiment

Physics uses models that describe phenomena

Although the physical world is very complex physicists often use models to explain the most fundamental features of various phenomena.

models- a pattern, plan, representation, or description designed to show the structure or workings of an object , system or concept.

Many of the models currently used in physics are mathematical models.

Physics models

When developing a model, physicist must decide which parts of the phenomenon are relevant and which parts can be disregarded .

For example , lets say you wish to study the motion of the ball.

Including the ball’s Surroundings ,size, spin,

Physics models

Weight ,color ,time in the air, speed, and sound when hitting the ground.

The first step toward simplifying this complicated situation is to decide what to study, that is, to define the system.

System-a set of particles or interacting components considered to be a distinct physical entity for the purpose of study.

Without models to simplify matters, situations such as building a car or sailing a boat would be to complex to study.

Models can help build hypothesis

A scientific hypothesis-is a reasonable explanation for observations that can be tested with additional experiment.

Lets considered the example of Galileo's “thought experiment", in which he modeled the behavior of falling objects in order to develop hypothesis about how object fell.

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Like Galileo’s hypothesis, any hypothesis must be tested in a controlled experiment.

Controlled experiment- an experiment that tests only one factor at a time by using a comparison of a control group with a experimental group.