Exploring the Scientific Method

What does a scientist do? Scientists need to Explore Observe Question Classify Make models Predicts consequences Make inferences Analyze information

Science The goal of science is to understand the world around us. A fact is a truth about nature that has been determined by observations or experimentation. No such thing as alternative facts – there is individual perception however. Scientists gather facts and then try to explain a phenomenon using a theory.

Theories in Science A theory is the most logical explanation for events that occur in nature. A scientific theory is a time-tested concept that makes useful and dependable predictions about the natural world. Theories must be tested many times and are often proven wrong, or added to when more information becomes available.

Laws in Science A law is a scientific theory that has survived many tests and never been proven wrong. A law summarizes observed experimental facts. Laws can changed or be proven wrong when new facts are uncovered.

The Scientific Method The scientific method is a systematic approach to problem solving. The steps of the scientific method are (although not always in this order): Stating the Problem Gathering Information on the Problem Forming a Hypothesis Performing Experiments to Test the Hypothesis Recording and Analyzing Data Stating a Conclusion Communicating the results Repeating the Work, if necessary

Stating a Problem You need to state a problem so that you can decide what topic to study. It is important to chose a problem that is specific. Ex. Do cars with more mass move faster down a hill than cars with less mass?

Gathering Information After stating a problem it is important to find out everything important that is related to the problem. Ex. What is mass? Ex. Have any experiments already been done on lighter & heavier cars?

Forming a Hypothesis A suggested solution to the problem is called a hypothesis. A hypothesis is formed after the important information about the problem has been reviewed. Hypotheses can be proven right but not proven wrong – data can SUPPORT (not prove) them. Ex. Cars with different masses should move down a ramp at the same speed.

Performing an Experiment Activities that test the hypothesis are called an experiment. It is very important to record the procedures and data, or results, of the experiment. Only one factor or variable can be tested at a time (manipulated or independent variable). We then measure the dependent variable, or what is affected by the change. A control is also used in experiments. This situation is identical to other trials, except the variable is left out.

Repeating the Work Experiments must be repeated several times to make sure the same conclusion is always reached and to check to see if the results are accurate. Usually 3-5 repeats are necessary.

Recording and Analyzing Data (dependent variables) During and after an experiment all data is recorded and analyzed. Data includes observations such as measurements (quantitative) or general observations (qualitative). Often graphs or tables are used to analyze (quantitative) data.

The mess needs to be cleaned up Types of Observations Quantitative Qualitative Mass Color Time Smell Others? Inferences vs Predictions Example: a broken egg is on the floor by the table. Inference (trying to explain or interpret what you observe based upon what you know) Prediction Has happened Will happen It rolled off the table The mess needs to be cleaned up

Stating a Conclusion After data is analyzed, a scientist states a conclusion. Conclusions either find the hypothesis was wrong or the hypothesis was right. Data from the experiment is used to support the conclusion. Ex. As evidenced by the similar average speeds of each car moving down a ramp, different masses do not make a difference in the car’s speed .