CHAPTER 1 Scientific Method

Scientific Method (yes, copy these steps!) The scientific method is a series of steps used to solve problems. Steps: 1. State a question 2. Background Information 3. Hypothesis 4. Experiment 5. Observe 6. Record data 7. Conclusion

State a Question (no, you don’t have to copy these slides. I’ll let you know when you have to start copying again :-D ) First step of the scientific method is to ask a question. Examples of a question could be: 1. Will different amounts of sea salt affect the reproduction rate of sea monkeys? 2. Could the acid in oranges have an effect on the growth of lima bean plants? 3. Are some magnetic materials more temperature Dependent that others?

Background Information  Background information is research about the topic of your experiment. Learning as much as possible about sea monkeys and their reproduction rate is useful before conducting your experiment. This allows for the formation of a good hypothesis.

Hypothesis A hypothesis is an educated guess on what you think might be the result of your experiment. IF 100 ml of sea salt is added to a water solution containing 200 ml of sea salt and sea monkeys THEN it will increase the rate at which sea monkeys reproduce.

Variables When conducting an experiment to solve a problem or answer a question variables are used. Variables factors that can change or stay the same. In the scientific method independent variable, dependent variable and control group are used.

Variables  An independent variable (also called the manipulated variable) is a factor that is intentionally changed in the experiment.  The dependent variable changes depending on changes done to the independent variable.

Independent and Dependent Variables The variables of the sea monkey experiment are: Independent variable (manipulated variable) is the different amounts of salt added to each tank. Dependent variable (responding variable) is what changed as a result of the different amounts of salt, the reproduction rate.

Control and Constant  The control group is the group that is not changed by the independent variable. In this case a tank that is not given a higher dose of sea salt.  A constant is something that does not change in the experiment. With the sea monkey experiment it could be the amount of water in each individual tank and the amount of sea monkeys in each tank.

Experiment  The next step is to conduct an experiment to test the hypothesis. In the sea monkey experiment the hypothesis stated that 100 ml of salt more than usual would increase the reproductive rate of sea monkeys. To test this hypothesis an experiment has to be conducted. Three tanks can be used in the experiment labeled 1, 2, and 3. Tank 1 is the control group. Tank 2 has 100 ml of salt more. Tank 3 has less than 100 ml of salt.

Gathering Data  The next step is to gather data. Observe the experiment and write down the results. Then make graphs or tables to illustrate the results.

Conclusion The final step in the scientific method is to write a conclusion.  The conclusion is the summary of the experiment, explaining if the hypothesis was correct. Sometimes the hypothesis is incorrect. In that case a new hypothesis is formed and new test are executed.

Theory vs. Law A scientific theory is a well tested explanation for a wide range of observations or experimental results. Scientists accept a theory only when there is a large body of evidence that supports it. However, future testing can still prove an accepted theory to be incorrect. A scientific law is a statement that describes what scientists expect to happen every time under a particular set of conditions. Unlike a theory, a law describes an observed pattern in nature without attempting to explain it.

What does any of this have to do with me? Scientific literacy means that you understand basic scientific terms and principles well enough that you can evaluate information, make personal decisions, and take part in public affairs. By having scientific literacy, you will be able to identify good sources of scientific information, evaluate them for accuracy, and apply the knowledge to questions or problems in your life.

Home learning Copy these questions: 1. What is meant by saying that a hypothesis must be testable? 2. At sea level, pure water boils at 100 degrees Celsius. Is this an example of a scientific theory or a law? Explain.