Responsible Experimental Design The Scientific Method

STEP 1: Ask a Scientific Question! The Scientific method is a series of steps followed to solve problems.The Scientific method is a series of steps followed to solve problems. To start the process of investigation you have to be curious about something. A scientific question is a very specific question that can be answered through observation, measurement, testing, or analysis.To start the process of investigation you have to be curious about something. A scientific question is a very specific question that can be answered through observation, measurement, testing, or analysis. Observation – the process of obtaining information by using the senses.Observation – the process of obtaining information by using the senses. Questioning a promotional claim can be a good starting point.Questioning a promotional claim can be a good starting point. Promotional claim – a statement used to sell a product, service, or concept.Promotional claim – a statement used to sell a product, service, or concept.

STEP 2: Form a Hypothesis! A hypothesis is an educated guess that answers your scientific question. It is based on inference, informed decision, logic, research, and experience.A hypothesis is an educated guess that answers your scientific question. It is based on inference, informed decision, logic, research, and experience. Inference – a prediction based on experience and knowledge rather than on direct observation.Inference – a prediction based on experience and knowledge rather than on direct observation. Informed decisions – conclusion that considers the data that are relevant to making a particular choice.Informed decisions – conclusion that considers the data that are relevant to making a particular choice. A hypothesis should be something that can be tested through an experiment. A hypothesis should be something that can be tested through an experiment. A controlled experiment is a procedure designed to test a hypothesis that includes a control group and experimental group.A controlled experiment is a procedure designed to test a hypothesis that includes a control group and experimental group.

STEP 3: Design an Experiment! Determine your variables - factors that can impact the results of the experiment.Determine your variables - factors that can impact the results of the experiment. There are two type of variables: Independent and dependent.There are two type of variables: Independent and dependent. Independent variables are changed or controlled by the experimenter.Independent variables are changed or controlled by the experimenter. Dependent variables are responses or results that you get after changing the independent variable.Dependent variables are responses or results that you get after changing the independent variable. Set up the experimental groups.Set up the experimental groups. Control group – represents what would happen if the independent variable was not manipulated.Control group – represents what would happen if the independent variable was not manipulated. Experimental group – the only thing different than the control group is the changes in the independent variable.Experimental group – the only thing different than the control group is the changes in the independent variable.

STEP 3: Design an Experiment! Experimental design must be guided by ethics. Ethics are standards of conduct and moral judgment. An example would be conducting research in way that reduces risks to people, animals, and the environment. Scientists must act responsibly and with integrity.Experimental design must be guided by ethics. Ethics are standards of conduct and moral judgment. An example would be conducting research in way that reduces risks to people, animals, and the environment. Scientists must act responsibly and with integrity.

STEP 3: Design an Experiment! You need to have an accurate, specific record of all of the steps of the experiment.You need to have an accurate, specific record of all of the steps of the experiment. This step-by-step plan is called the procedure.This step-by-step plan is called the procedure. Your procedure should be clear enough that another scientist or science student could repeat the experiment and verify your results.Your procedure should be clear enough that another scientist or science student could repeat the experiment and verify your results.

Step 4: Analyze the Data. Data (this is plural) are information collected through scientific research.Data (this is plural) are information collected through scientific research. Data can be…Data can be… Notes,Notes, Drawings,Drawings, Measurements, orMeasurements, or ObservationsObservations

Step 4: Analyze the Data. Data collected in numerical form are called quantitative data.Data collected in numerical form are called quantitative data. Quantitative data can be analyzed by knowing the range of the data and by finding the mean, median, and mode of the data.Quantitative data can be analyzed by knowing the range of the data and by finding the mean, median, and mode of the data. Qualitative data describe an object in words rather than in numbers.Qualitative data describe an object in words rather than in numbers.

Step 5: Form a Conclusion! Your conclusion should explain the results of the experiment and show any relationships that exist between the variables. Your conclusion should also state whether the data support your hypothesis or not.Your conclusion should explain the results of the experiment and show any relationships that exist between the variables. Your conclusion should also state whether the data support your hypothesis or not. Conclusions must be objective – based on facts and free of bias. Bias is a personal prejudice or slanted point of view.Conclusions must be objective – based on facts and free of bias. Bias is a personal prejudice or slanted point of view.

Good experiments include multiple trials! Each time you modify or conduct the experiment the new experiment is called a trial.Each time you modify or conduct the experiment the new experiment is called a trial. For a hypothesis to be accepted many trials must be conducted to make sure the results turn out the same each time!! This helps to increase the accuracy, reliability, and validity of the experiment.For a hypothesis to be accepted many trials must be conducted to make sure the results turn out the same each time!! This helps to increase the accuracy, reliability, and validity of the experiment. Accuracy refers to the correctness of a measurement or conclusion!!Accuracy refers to the correctness of a measurement or conclusion!! Precision describes the exactness of the process. Your procedure should be able to be replicated!Precision describes the exactness of the process. Your procedure should be able to be replicated! Reliability refers to the level of trust you can place in information.Reliability refers to the level of trust you can place in information. Experiments with validity are known to be based on facts and truth.Experiments with validity are known to be based on facts and truth.

Theory vs. Law After many trials, hypotheses may be accepted as theory. A theory is a tested explanation for hypotheses and observations.After many trials, hypotheses may be accepted as theory. A theory is a tested explanation for hypotheses and observations. Laws do not explain how or why something happens. A scientific law summarizes repeated observations.Laws do not explain how or why something happens. A scientific law summarizes repeated observations. For example: the law of gravity tells us that every time we drop an object it will fall. The law does not explain how or why it will fall, just that it will fall.For example: the law of gravity tells us that every time we drop an object it will fall. The law does not explain how or why it will fall, just that it will fall.