The Nature of Science: Exploring the World Around Us

1. Chapter 1: The Nature of Science 1-1 What is Science?

2. 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

3. Chapter 1: The Nature of Science 1-2 The Scientific Method

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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

12. The Scientific Method – An Everyday Experience • Scientists are not the only people who use the scientific method • Auto mechanics • Plumbers • Electricians

13. 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

14. 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-

15. 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

16. 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

17. 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

18. Chapter 1: The Nature of Science 1-3 Science: “Facts” and “Truth”

19. 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

20. 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

21. Chapter 1: The Nature of Science 1-5 The Spaceship Called Earth

22. 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