The Scientific Method

Introduction to science, biology, and experimental design

What is biology?

• Bio = living• Ology = study of • So, biology means … ? • Can you think of any other words that

start with bio?• Can you think of any other words that

end with -ology?

What is science?

• The goal of science is to:• Investigate the natural world• To explain events in the natural world• And to use those explanations to make

useful predictions

• How do scientists do this?

Thinking like a scientist

• Scientific thinking usually starts with an observation. • Process of gathering information about

events or processes in an orderly way• Use senses• The information gathered from

observations is called data

Types of data

• There are two types of data:• 1. Quantitative: expressed as numbers• 2. Qualitative: descriptive and involve

characteristics that can’t usually be counted

• Think quality

What comes after an observation?

• Hypothesis• An educated guess • Testable!! • Hypotheses may be wrong, and that’s ok• It can be changed • Typically an “if,” “then” statement • Short and definitive

How Scientists Work

• 1. Define the problem. Make sure only one problem is being studied• Done through observation

• 2. Research the problem. Use all available resources to collect data on the subject

• 3. Develop a hypothesis • 4. Develop a controlled experiement.

Controlled Experiment

• SAFETY!!! • Experiment: a procedure that tests a hypothesis by

the process of collecting information under controlled conditions• 1. control: the standard or group in which all conditions are

kept the same• 2. experimental: the test group where only ONE variable is

altered• 3. Independent variable: the condition that is being changed

(a.k.a. manipulated variable)• 4. dependent variable: measurable condition resulting from

change in the experiment (a.k.a. responding variable)

Next …

• 5. Gather and analyze data: process in which scientists gather information (data) about their experiments • Thinking about what happened • How can scientists gather and organize

information?

Helpful Hint

• DRY MIX

• DRY• Dependent variable• Responding variable• Y-axis

• MIX• Manipulated variable• Independent variable• X-axis

Last Step

• 6. Forming conclusions• May or may not support the hypothesis

(and that’s ok!)• Additional experimentation to build

documentation• If the hypothesis is wrong, change the

hypothesis, NOT THE DATA!! • Why?

Other Information to Consider

• Reporting results• Who’s interested

• Verifying results• Experiments should be re-testable• Plagiarism• Falsifying data

How do theories and laws develop?

• Theory: well tested explanation that unifies a broad range of observations• May become a dominant view, but is not an

absolute truth

• Law: well tested explanation that is dependable enough to be a “law” • One step further than a theory

When experiments are not possible

• Animals in the wild• Humans• Values and ethics

A little practice

• Your report is due tomorrow morning and it must be typed on the computer. You enter the report in the computer and then give the command to print. Nothing happens. No, this is not a nightmare. It is really happening, and you need help. What do you do?• State the problem• Form a hypothesis• How will you test your hypothesis?• Where were the results of your experiment?• What can you conclude?

More practice

• You have just baked your first batch of cookies for the school bake sale, but find that the cookies are too hard and dry. Assuming you have enough time to make more cookies, describe the steps you would take to solve the problem.• State the problem.• Form a hypothesis.• How will you test your hypothesis?• What were the results of your experiment?• What can you conclude?

Scientific Method Graphic Organizer:Use these terms to fill in the blanks

• Communicate the results

• Analyze the data• Create an experiment• Modify the experiment• Identify the problem• Form a hypothesis• Perform the experiment

• Process• Answers• Information• Guess• Educated• Steps• Problem• Question• Organized