The Scientific Method

The Scientific Method The Scientific Method is a problem solving-strategy. *It is just a series of steps that can be used to solve any problem.

Step 1: State the Problem *Before you can begin to think of an experiment, you have to know what you want to know an answer to. Often, scientists will ask a question. *Before you can begin to think of an experiment, you have to know what you want to know an answer to. Often, scientists will ask a question. In this step, a scientist will figure out exactly what they want to know. In this step, a scientist will figure out exactly what they want to know. EXAMPLE: EXAMPLE:

Step 2: Gather Information *Before you can find the answer to a question, you must figure out what you already know. *Before you can find the answer to a question, you must figure out what you already know. In this step, scientists will do research on their subject. In this step, scientists will do research on their subject.EXAMPLE:

Step 3: State a Hypothesis *This is an answer to the question. It is more than just an educated guess. It is actually what you think the best answer is after you have done some research. *This is an answer to the question. It is more than just an educated guess. It is actually what you think the best answer is after you have done some research. In this step, scientists state their solution to the problem, or their answer to the question. In this step, scientists state their solution to the problem, or their answer to the question. EXAMPLE: EXAMPLE:

Step 4: Test the Hypothesis *Just because you come up with an answer, it does not mean it is the best answer. Somehow, you have to do something to prove that your hypothesis is correct. *Just because you come up with an answer, it does not mean it is the best answer. Somehow, you have to do something to prove that your hypothesis is correct. In this step, scientists design experiments to prove that their hypothesis is correct. Then they will do the experiment and gather data. In this step, scientists design experiments to prove that their hypothesis is correct. Then they will do the experiment and gather data. EXAMPLE: EXAMPLE:

Step 5: Record and Analyze the Data *After an experiment, you might have a stack of surveys or a bunch of numbers. These need to be organized into data tables, charts, and graphs before any patterns, trends, or relationships can be seen. In this part, it is important to note all possible observations that relate to the experiment. *After an experiment, you might have a stack of surveys or a bunch of numbers. These need to be organized into data tables, charts, and graphs before any patterns, trends, or relationships can be seen. In this part, it is important to note all possible observations that relate to the experiment. In this step, scientists organize the information they collected in data tables, charts, and graphs. In this step, scientists organize the information they collected in data tables, charts, and graphs. EXAMPLE: EXAMPLE:

Step 6: State the Conclusion *After you have analyzed the information you gather, you are able to say of your hypothesis was right or not. If you are right, say why. If you are wrong, try to figure out why or think of other answers to the problem that other scientists may want to try. *After you have analyzed the information you gather, you are able to say of your hypothesis was right or not. If you are right, say why. If you are wrong, try to figure out why or think of other answers to the problem that other scientists may want to try. In this step, scientists state if their hypothesis was correct or not and explain how their experiment proves this. In this step, scientists state if their hypothesis was correct or not and explain how their experiment proves this. EXAMPLE: EXAMPLE:

Step 7: Repeat the Work *After an experiment is complete, scientists will often repeat them for different reasons. If the hypothesis was right, someone may try the whole experiment again, just to verify the results. If the hypothesis was wrong, they may try something else based on what was stated in the conclusion. *After an experiment is complete, scientists will often repeat them for different reasons. If the hypothesis was right, someone may try the whole experiment again, just to verify the results. If the hypothesis was wrong, they may try something else based on what was stated in the conclusion. In this step, scientists will repeat the whole process. This can either be done as a check to make sure what the scientists say is true really is, or to try a completely new hypothesis. In this step, scientists will repeat the whole process. This can either be done as a check to make sure what the scientists say is true really is, or to try a completely new hypothesis. EXAMPLE: EXAMPLE:

What’s the Point? After scientists test their hypothesis, they will report their findings in a scientific journal. MOST experiments actually prove the hypothesis wrong. BUT, the scientists still report what they did so they can show others what they learned. After scientists test their hypothesis, they will report their findings in a scientific journal. MOST experiments actually prove the hypothesis wrong. BUT, the scientists still report what they did so they can show others what they learned.

CONTROLLED EXPERIMENTS

*Controlled experiments are run to *Controlled experiments are run to prove a hypothesis. *Most importantly, there must be at least two different experiments that are actually being done. *Most importantly, there must be at least two different experiments that are actually being done.

*When designing the experiment, the scientist must determine exactly what they are going to test. Then they have to figure out how experiment would run under “normal” conditions. They have to arrange an experiment to show how things normally happen. *When designing the experiment, the scientist must determine exactly what they are going to test. Then they have to figure out how experiment would run under “normal” conditions. They have to arrange an experiment to show how things normally happen. This is the CONTROL, or what they are using to compare their results to.

Basically, scientists will try to make their experiment run different from normal. If they want to make sure that they are only testing their hypothesis and that nothing else is affecting the results, they must identify only one thing that can be changed. The only thing different is called the EXPERIMENTAL VARIABLE. Basically, scientists will try to make their experiment run different from normal. If they want to make sure that they are only testing their hypothesis and that nothing else is affecting the results, they must identify only one thing that can be changed. The only thing different is called the EXPERIMENTAL VARIABLE.

TO SUM IT UP: A controlled experiment actually has two “set-ups:” A controlled experiment actually has two “set-ups:” The control and the experimental. The control and the experimental. These two set-ups are exactly the same, except for the experimental variable. These two set-ups are exactly the same, except for the experimental variable. There can only be one thing different between the set-ups if you want to prove that the variable is actually making a difference. There can only be one thing different between the set-ups if you want to prove that the variable is actually making a difference.

POINTS TO REMEMBER: *To make sure results are accurate, experiments should be done many times, or with a large sample size. This is because there is always something different each time. *To make sure results are accurate, experiments should be done many times, or with a large sample size. This is because there is always something different each time. The more tests that are done, the closer you can get to an “average” result.

*The word “variable” means many things. Keep it straight. THE VARIABLE THE VARIABLE In controlled experiments, it is the only difference between the control and the experimental set-up. In controlled experiments, it is the only difference between the control and the experimental set-up. ow_to_annoy_a_plant/

EXPERIMENTAL VARIABLES Things that change or could change in an experiment. Things that change or could change in an experiment. CONSTANT VARIABLES CONSTANT VARIABLES All factors that could change, but should be the same. All factors that could change, but should be the same. EX: Sunlight, water, soil, living conditions, food, types of plants/ animals being tested EX: Sunlight, water, soil, living conditions, food, types of plants/ animals being tested INDEPENDENT VARIABLE (Manipulative) INDEPENDENT VARIABLE (Manipulative) A measurable quantity in an experiment. The scientist has control over these values and can be set up ahead of time on a graph. A measurable quantity in an experiment. The scientist has control over these values and can be set up ahead of time on a graph. EX: Time –the experimenter decides if it will be collected every minute, every 5 minutes, etc. This can be plotted on a data table and/or graph well before the experiment happens. EX: Time –the experimenter decides if it will be collected every minute, every 5 minutes, etc. This can be plotted on a data table and/or graph well before the experiment happens. DEPENDENT VARIABLE (Responding) DEPENDENT VARIABLE (Responding) Another measurable quantity in an experiment. This is often the reason for doing the experiment. This is the information you want to know and the values can not be plotted ahead of time. Another measurable quantity in an experiment. This is often the reason for doing the experiment. This is the information you want to know and the values can not be plotted ahead of time. EX: Temperature –This often depends on how long the experiment has been running. EX: Temperature –This often depends on how long the experiment has been running.

In a controlled experiment, you must explicitly keep all variables constant except the one you are manipulating. For instance, if you want to test response to wet vs. dry conditions, the light, temperature, chemicals in the filter paper or on the dish surface, and movement of the table must all remain constant. In addition, all the experimental organisms must be of the same approximate age, size, and state of health. It is not enough to say you will hold all variables constant; you must explain how you will do this, and do it! It is not enough to say you will hold all variables constant; you must explain how you will do this, and do it! abbench/lab11/control.html