Designing an Experiment

Flow Chart of Scientific Method- brainpop

What is an experiment? It is an organized plan to test a hypothesis. An experiment follows a definite plan. It documents data gathered. It attempts to answer a question(s).

Components of an Experiment 1. The Question, Purpose, or Reason for the experiment 2. Research – find background info to help with the experiment. 3. The HYPOTHESIS

Components of an Experiment 4. The Experimental Phase Materials Procedures

Components of an Experiment 5. Results 6. Conclusions

I. Posing a QUESTION 1. Design the experiment to solve the question or problem. 2. Narrow down the question — be specific about what you want to find out. 3. Investigate one “?” at a time.

III. Develop a HYPOTHESIS A hypothesis is based on observations and previous knowledge or experience 1. It MUST be testable. 2. It is a POSSIBLE ANSWER to your question. 3. A hypothesis takes the form of an If… then… Statement.

Variables A variable is any factor that can change in an experiment. Variables must be identified in order to test the hypothesis.

Identifying the Variables Types of variables: 1. Manipulated Variable a. Also known as the independent variable b. The factor you will be purposely. changing and testing. c. is shown on the horizontal axis of a graph.

Identifying the Variables 2. Responding Variable a. also known as dependent variable b. The variable you predict will change as a result of the manipulated variable. c. Is shown on the vertical axis of a graph

If… then… statements If (manipulated or independent variable) , then (dependent variable). A hypothesis is written as an If… then… statement. These statements must be written in correct grammatical form.

IV. The Experiment Materials – make a list of all the materials needed to conduct your experiment.

III. The Experiment Procedures (How to do the experiment)

The Procedures Includes a brief description of the experiment. Identifies a plan to collect data and the variables Listed in numbered step-by-step description of how to conduct the experiment.

(Procedures – cont’d) Prepare a data table Record - How the manipulated variable effects the responding variable

A “Controlled” Experiment 1. All conditions (variables) are kept the same except for the manipulated variable. 2. A “control” is used as a comparison in the experiment. (A standard against which to measure results.)

V. Gathering & Interpreting Data Gather your data during the experiment in a data table and log.

V. Gathering & Interpreting Data Make a graph from the data table

V. Gathering & Interpreting Data Explain the data: Look for comparisons, trends, patterns Make inferences from data and compare them with what you already know Ask & answer: how, what, why.

VI. Conclusion - Your reflections on what happened in the experiment. Compare data and graph with your hypothesis and decide whether the hypothesis is true or false.

VI. Conclusion Reflect upon & discuss your how, what, why answers.

VI. Conclusion Raise new questions and redesign a new experiment.

VI. Conclusion Make a statements that summarize what “you” have learned from the experiment.

Science is…