Chapter 1: The Nature of Science 1-1 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 1-2 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 autumn  As 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 cm 3 ) 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 ( o C)  Water freezes at 0 o C and boils at 100 o C  Human body temp – 37 o C  Room temperature – 21 o C

Chapter 1: The Nature of Science 1-3 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 1-5 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