Chapter 1: The Nature of Science

1-1 What is Science?

What is Science? Asking questions about the world around us is part of

human nature There are several ways to explain the world around us One way is to assume that all events in nature have

natural causes We can then try to arrange a series of observations or

tests to learn what those causes are Science is the word that we apply to this process The goal of science is to understand the world

around us There are many important fields of study that are not

considered sciences The scientific method helps to distinguish science

from non-science

Chapter 1: The Nature of Science

1-2The Scientific Method

The Scientific Method The scientific method consists of several

steps: Observing and stating a problem Forming a hypothesis Testing the hypothesis Recording and analyzing data Forming a conclusion Replicating the work

Observing and Stating a Problem Starts with an observation

Example: leaves changing color in autumnAs curious scientists, we would then be

interested in discovering why this color change takes place

Forming a Hypothesis We proceed to gather information that

helps us generate a hypothesis A hypothesis is a possible explanation,

a preliminary conclusion, or even a guess about some event in nature

A hypothesis is usually an “if…then…” statement when in written form

Testing the Hypothesis Next we must test our hypothesis Normal testing involves using controlled

experiments Controlled experiments allow researchers to

isolate and test the effects of a single factor, or variable

The control setup is the setup that remains unchanged

The experimental setup is identical to the control setup in every respect except for one

Recording and Analyzing Data When performing experiments it is

important to keep careful records of observations and information, or data

Most people arrange their data in the form of tables and graphs

Forming a Conclusion After viewing the data you should be

able to develop a conclusion about your hypothesis

Was it correct? If the hypothesis was not correct, it is

not necessarily a bad experiment, now you just know that another factor must be causing the change, thus causing you to revise your experiment

Replicating the Work The best scientific experiments can be

replicated, or reproduced It must be possible for either the original

experimenter or other researchers to duplicate

If interesting results come from an experiment, a researcher will publish a report of the work in a scientific journal

The report must contain enough detail so that other scientists can copy the experiment precisely to see if the same results continue to occur

Hypotheses and Theories When a hypothesis is tested and

confirmed often enough that it is unlikely to be disproved by future tests, it may become worthy of being called a theory

Scientific theories are not just hunches or hypotheses

They are powerful, time-tested concepts that make useful and dependable predictions about the natural world

The Scientific Method – An Everyday Experience Scientists are not the only people who

use the scientific method Auto mechanics Plumbers Electricians

A Universal Language – The Metric System Because most experiments involve

measurements, researchers need a universal system of measurement in which to present their findings

Scientists use the metric system of length, volume, mass, and temperature when describing experiments and data

The metric system is a decimal system based on certain standards and scaled on multiples of 10 Also known as the International System of

Units, or SI

Length The basic unit of length is the meter (m) 1m = 39.4in Scientists use prefixes to describe

measures that are smaller or larger than the meter centi- milli- kilo-

Volume Volume is the amount of space an

object occupies Liter (L) for liquids; cubic

centimeter (cc, or cm3) for solids Volume = L x W x H

Mass and Weight Mass is a measure of the amount of matter in

an object Weight is a measure of the pull of gravity on

that mass Often used interchangeably The basic metric unit scientists use to

describe mass is the kilogram (kg) 1kg = 2.2 lbs The mass of small objects is measured in

grams (g) 1g = 1/1000 kg

Temperature The metric system measures

temperature using the Celsius scale (oC)

Water freezes at 0oC and boils at 100oC

Human body temp – 37oC Room temperature – 21oC

Chapter 1: The Nature of Science

1-3Science: “Facts” and “Truth”

Science: “Facts” and “Truth” Scientific knowledge is a constantly

changing body of observations Then– Earth was flat, sun revolved around the

Earth, rain fell through holes in heaven from a huge water tank

Now– Earth is round, Earth revolves around the sun, rain falls from clouds made of water vapor

New discoveries are constantly being made Without a doubt, some of what you learn this

year will have to be changed one day

How to Study Science Do not try to memorize the contents

of the textbook as a list of separate facts

Arrange facts you need to know in groups according to subject

Work at understanding, rather than just memorizing, the topics we talk about

Remember that science is a process

Chapter 1: The Nature of Science

1-5The Spaceship Called Earth

The Spaceship Called Earth Earlier in human history, the Earth seemed to

be without end There were always new wildernesses to settle,

new resources for use, and plenty of places to dump our garbage

Now we know there is limited land – and limited amounts of clean air, water, and other resources

The Earth is no longer a planet without end. It is more like a spaceship with a living cargo, carrying limited amounts of supplies