Biology and YouChapter 1

Scientific thought involves: Making observations

Using evidence to draw conclusions

Being skeptical about ideas

Being open to change when new discoveries are made

Chapter 1: Section 1-The Nature of Science

SCIENTIFIC THOUGHT

Science is governed by truths that are valid everywhere in the universe.

Though branches of science address different aspects of the natural world, universal laws apply to all branches of science and every person.

Examples: law of gravity, law of conservation of energy

Chapter 1: Section 1-The Nature of Science

UNIVERSAL LAWS

Ethics are a system of moral principles and values.

Scientists performing investigations must:

Report only accurate data Allow peers to review their work Behave ethically with people involved in research

SCIENCE & ETHICS

Chapter 1: Section 1-The Nature of Science

A broad understanding of science can help you:

Take better care of your health Be a wiser consumer Become a better informed citizen

You can use science to investigate a problem in your community and discover helpful solutions

WHY STUDY SCIENCE?

Chapter 1: Section 1-The Nature of Science

Observation The act of noting or perceiving object or events

using the senses.

Hypothesis A possible explanation that can be tested by

observation or experimentation

BEGINNING A SCIENTIFIC INVESTIGATION

Chapter 1: Section 2-Scientific Methods

Experiment A procedure that is carried out under controlled

conditions to test the hypothesis A controlled experiment tests one factor at a time

and uses a control group and an experimental group

CONTROL GROUP: serves as a standard for comparison in an experiment

EXPERIMENTAL GROUP: identical to control group except for one factor that is changed, which is called a variable

SCIENTIFIC EXPERIMENTS

Chapter 1: Section 2-Scientific Methods

The single factor that scientists change in an experiment is called the independent variable

Factors that may change is response to the independent variable are called dependent variables

NOTE:Some experiments may not be possible or be ethical to perform. In these cases, researchers perform studies.

SCIENTIFIC EXPERIMENTS 2

Chapter 1: Section 2-Scientific Methods

After conducting an experiment, researchers…

Analyze their results to learn if they support the hypothesis or not

Draw conclusions that explain the results of their experiment

They then verify their conclusions by repeating their experiment many, many times and by checking to see if other researchers get the same results

◦ Every person has his or her own point of view. A particular point of view is called bias.

SCIENTIFIC EXPERIMENTS 3

Chapter 1: Section 2-Scientific Methods

THEORY A system of ideas that explains many related

observations and is supported by a large body of evidence

If the results of a scientific experiment can be reproduced many times, the research may help develop a new theory.

Future research may also cause a theory to be revised or rejected.

SCIENTIFIC EXPERIMENTS 4

Chapter 1: Section 2-Scientific Methods

SCIENTIFIC

METHOD

Chapter 1: Section 2-Scientific Methods

Measurements taken by scientists are expressed in the International System of Units (SI), which is the official name of the metric system.

The International System of Units is used by all Scientists because they need to share a common measurement system.

SI is scaled in multiples of 10

MEASUREMENT SYSTEMS

SI is a decimal system. All relationships between SI units are based on powers of 10.

Most SI units have a prefix that indicates the relationship of that unit to a base unit.

Example: kilo- means 1,000. 1kilogram = 1,000 grams (grams is the base unit)

MEASUREMENT SYSTEMS 2

SOME SI PREFIXES

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METRIC UNITS OF LENGTH & EQUIVALENTS

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Scientists always: Keep detailed & accurate notes Perform precise measurements

Scientists also use specialized tools & techniques

Ex. Microscopes, sterile techniques, satellites, etc.

LAB TECHNIQUES

Light Microscope

Electron Microscope Transmission Electron Microscope

Scanning Electron Microscope

Microscope Images

TYPES OF MICROSCOPES

LIGHT MICROSCOPE

ELECTRON MICROSCOPES

Transmission Electron Microscope

Scanning Electron Microscope

When working in the laboratory, you must use caution to avoid things like:

Chemical burns Exposure to radiation Exposure to infectious disease Animal bites Poisonous plants etc.

Always follow all guidelines and lab procedures

Know where to find and how to use all laboratory safety equipment

LABORATORY SAFETY