The way we (scientists) do things. SCIENTIFIC METHOD The way we (scientists) do things. Scientists have a unique way of looking at the world. They want to know more about their world. They follow a set of rules for governing their research.

OBSERVATIONS All of us make everyday observations. Observations lead to questions about the world around us. Scientists want answers to these questions.

Overview

Problem Statement A problem statement states the question raised by observations. Problem statements often begin with “why” or “how” or “what if.”

Research Maybe someone already knows the answer to your question. Sources include: - Past relevant experiments - Encyclopedias - Scientific Journals - RELIABLE Online Resources Must be in your OWN WORDS Proper Citing is important! Give credit where it is due

Hypothesis A hypothesis states what the scientist believes to be the answer to the problem statement. A hypothesis draws on all the background known about the problem. Hypotheses are formatted, “If,…then,…because….”

Test the Hypothesis Experiments test your hypothesis. The best experimental design is “controlled.”

Controlled Experimentation When designing the experiment, the researcher carefully controls as many variables as possible. Variables - things that may be expected to change during the course of an experiment. Ex.: temperature, humidity, sunlight, etc. Three types: Dependent variable – the one the investigator measures. Ex.: growth rate Independent – what the investigator deliberately changes during the experiment; factors that will directly affect the dependent variable. Ex.: amount or type of fertilizer, temperature, amount of water. ONLY ONE (1) independent variable can be tested at a time. Standardized (controlled) – factors that are kept equal for all groups. Ex.: If groups get different amounts of fertilizer, then the type of fertilizer must be the same for all groups.

Controlled Experimentation In most experiments there is a control group and experimental groups. The two groups are as similar as possible, but the treatment group is the one that experiences the variable that you’re studying. Control Group – group in which the independent variable is either eliminated or set at a standard value. You MUST have a control group in order to be able to measure the effects of your independent variable upon the dependent variable. Experimental Group(s) – groups which are being exposed to the independent variable.

Collect Data The results of an experiment are called “data.” Scientists use their five senses to collect data.

Collect Data Scientists often use specialized equipment to help them collect their data.

Analyze Data Now that you have your data, you must make sense of it. Scientists use: Charts Tables Graphs Equations

What does the data mean? There are two options: The evidence supports the hypothesis. The evidence is inconsistent with the hypothesis.

What do you do? If the data is inconsistent with the hypothesis, you revise your hypothesis in light of your new information. Then you design a new experiment.

OK, I’ve got it all right. Now what? Tell everyone, silly! Scientists publish their findings to share what they’ve discovered with other scientists (and to brag a little, too.)

What do you do? If the data supports the hypothesis, you repeat the experiment several times to make sure you did everything right.

Summary