Scientific Method Notes PDF

Scientific Method How to think like a scientist. Steps in the Scientific Method n Observation n Hypothesis n Experiment n Data Collection n Retest n Conclusion List as much information a...

Scientific Method How to think like a scientist. Steps in the Scientific Method n Observation n Hypothesis n Experiment n Data Collection n Retest n Conclusion List as much information as you can about this picture. You have 30 seconds… Let’s look at the data that you have collected. Observations n Gathered through your senses and measurements. n Qualitative n Quantitative n A scientist notices a “problem” in their natural world. Observations n An example of an observation might be: n It takes me 15 minutes to walk home from school every day. Making an Inference n Logically explains an observation. n Always tentative and are not considered “wrong”. n Are changed when new data is obtained. n Influenced by knowledge, experience and opinion. Types of Investigations n There are 3 ways in which scientists learn about the outside world: n Descriptive n Comparative n Experimental Descriptive Investigations n Primarily use qualitative observations. n Can be open to interpretation. n Generally have multiple variables. Comparative Investigations n Can include both qualitative and quantitative observations. n Not as subjective as descriptive investigations. n Can have fewer variables. Experimental Investigations n Focus primarily on quantitative measures. n Completely objective. n Should only have one variable. n Can be repeated by another scientist. Hypothesis n A suggested solution to the problem. n Must be testable. n Sometimes written as: n If…then… n I believe that… n Predicts an outcome. Hypothesis n An example of a hypothesis might be: n If I take a different route home, then I can get there quicker. Experiment n A procedure to test the hypothesis. n Contains variables or factors being tested and controlled. Experiment n There are 3 types of variables: n Control (constant) n Independent (manipulated) n Dependent (responsive) Experiment n A good or “valid” experiment will only have ONE manipulated variable! n A good scientist will change one variable to measure what happens. Types of Variables n The scientist makes a special effort to keep most factors constant so that they will not effect the outcome. n Those factors are called control variables. What is the Purpose of a Control? n Controls are NOT being tested. n Controls are used for COMPARISON. Types of Variables n The factor that the scientist changes is known as the independent variable. n The factor that the scientist measures or observes is called the dependent variable. Example of Controls & Variables n You want to figure out the fastest route to walk home from school. You will try several different routes and time how long it takes you to get home by each one. Since you are only interested in finding a route that is fastest for you, you will do the walking yourself. What are the Variables in Your Experiment? n Varying the route is the independent variable. n The time it takes is the dependent variable. n Keeping the same walker throughout makes the walker a control variable. Validate, validate, validate! n Remember, to be a valid experiment: n Two groups are required: n Control n Experimental n There should be only one manipulated variable. Data n Results of the experiment. n May be quantitative (numbers) or qualitative (qualities). Data n Must be organized… n into charts, tables, or graphs. n … and usable.  Retest n One more thing… it is best to make several trials with each independent variable. A T E! VALID L I D ATE! V A VALIDA D AT E ! T E ! VA L I A T E ! VA L I D VALIDATE! VALIDATE! Conclusion n The answer to the hypothesis based on the data obtained from the experiment. n Were you right or wrong? Conclusion n CER Method n Claim n Evidence n Reasoning n I believe that by changing my route, I can get home faster. After trying three different paths, I found that the route through Mr. Cummings’ yard was the fastest. Solving a Problem 1) Identify a problem. 2) State observations about the problem. 3) Form a hypothesis about the problem (If…then…). 4) Design an experiment to test the hypothesis. 5) Collect data. 6) Retest. 7) Form a conclusion.