Scientific Method

Science

• Science: A way of learning about the natural world

– Includes all of the knowledge gained by exploring the natural world – This knowledge is always growing and changing as scientists ask new questions and explore new ideas

Scientific Inquiry

• Scientific: Of or relating to the practice of science• Inquiry: A close examination of a matter in a search for information or truth• Scientific Inquiry: The ways in which scientists explore the natural world

How Does Scientific Inquiry Work?

• Scientific Method: – Make observations and/or inferences – Ask questions – Develop hypotheses – Design experiments – Make measurements – Collect data – Interpret data – Draw conclusions – Communicate

Ask Questions

• Scientific inquiry begins with a question or a problem

Make Observations and InferencesMake Observations and Inferences

• Observation: Using one or more of your senses to collect data• Inference: An interpretation of an observation that is based on

evidence or prior knowledge• Data: Facts, figures and other evidence gathered through observation

Making Inferences

• An inference is only one of many possible interpretations of the observation

Developing Hypotheses

• Hypothesis: A possible explanation for a set of observations or answer to a scientific question• A hypothesis must be something that can be tested• Hypotheses can either be supported or disproved

Designing an experiment totest a hypothesis

• After you state your hypothesis, you must design an experiment to test it.

Experiment Variables

• Variable: Factors that can change in an experiment• Independent Variable: The variable that is changed during the experiment• Dependent Variable: The factor that changes because of the manipulated variable

Controlled Experiments

• Control: not being tested, used for COMPARISON

• Scientific experiments MUST be controlled!

Making Measurements andCollecting Data

• Scientists have developed a standard system of measurement called The International System of Units (SI)• Why do scientists need a standard system of measurement?

Interpreting Data

• After the data are collected, they must be organized and interpreted• How can data be organized so that is easy to understand?

Presenting Data Table vs. Graph

Why do you think information is often presented in graphs instead of just in a list or table?

What are some kinds of graphs?

• Bar graph • Line graph • Pie chart

Visual representations to display a relationship not apparent in data tables

Bar Graph What’s your favorite color?

When would you use a bar graph?

- Categories - Changes over time

What is the best way to present this data?

Dec-’04 1Dec-’05 5.5Dec-’06 12Dec-’07 50Dec-’08 100Dec-’09 300Dec ‘10 550 Aug ‘11 700

Number of Facebook users in Millions

Line Graph

Where do we see line graphs?

Data

Energy in New Jersey 51% Nuclear 33% Natural Gas 14% Coal 2% Renewable ( Solar/Wind/

Hydroelectric)1% Oil

Pie Chart

Line Graphs

Which should you use more in science?

How to represent this data?

Drawing Conclusions

• After you have organized and interpreted your data, you must draw a conclusion.• You need to decide if the data support your original hypothesis.

Communicating

• Scientists must communicate their findings to other scientists. This contributes to the growth of the body of scientific knowledge.

Scientific Theories

• Scientific Theory: A well-tested concept that explains a wide range of observations.• A theory is based on thousands of experiments done by different scientists.• Future testing may prove a theory to be incorrect