Scientific Method
Beginnings Aristotle (384 BCE-322 BCE or BC) ancient Greek philosopher VERY INFLUENTIAL Aristotle was so famous that his work influenced thinking in the Western world from his time to the present. This was fine when he was right. But he was so influential that his mistakes were never noticed.
Aristotle and his contemporaries believed that all problems could be solved by thinking about them. Sometimes this worked, other times it did not. For example, Aristotle thought that heavy objects would fall faster than lighter ones.
Now that does seem reasonable at first. And this is how science was done in ancient times. But what did Aristotle not do? He never tested his ideas! The world would have to wait almost 2000 years for that to happen.
1564-1642 AD or CE Galileo Galilei Lived in what is today Italy Is considered to be the first true scientist. Why???? Because he actually did the experiment.
Aristotle said that heavy objects fall faster than lighter ones. So Galileo asked, How much faster? So he sent students up to the top of a building and had them drop a heavy ball and a lighter one off at the same time. He had other students waiting below to measure the difference in time between the two hitting the ground.
Today of course we know what happened. Much to everyone s surprise both balls hit the ground at about the same time! This shows that it is much preferred to test your ideas rather than merely think about them. One test is worth a thousand expert opinions. Bill Nye
Scientific Method Steps 1. Observe the natural world around you - observations and inferences 2. State the problem. 3. Research and gather information 4. Make/Form a hypothesis. 5. Test the hypothesis a. Conduct the experiment. b. Build a model 6. Record/analyze data. 7. Make/draw a conclusion. a. Report findings to others so they can repeat the experiment. b. Modify hypothesis
Observe the Natural World Around You Observations: We use our senses to gather information about the world around us. There are two types of observations.
Quantitative Quantitative observation: (quantity) How many. Will always have a number. Based on exact measurement. The room is 8 meters across. Sarah is 141-cm tall. Sam weighs 450 Newtons.
Qualitative Qualitative observation: (quality) Usually made with our senses. Color, shape, feel, taste, sound. Olivia is wearing a blue sweater. The lab tabletop is smooth. The dog s fur is shiny.
Inferences Inference: A logical interpretation of an event that is based on observations and prior knowledge. What does this mean in 9th grade terms?
Making Inferences You are at the counter in the office to get a bus pass signed. You see a student leave the principal s office crying and upset. We could make an inference as to why the student is upset. Could be in trouble (ISS, OSS, expelled) Family problems at home (sick, accident) Student not feeling well Student has poor grades (failing, retention)
Research and Gather Information Learn as much as possible about the background of the problem. - Have others found information that will help you determine the tests to do and which tests will be helpful?
State the Problem Why does it happen? How does it happen?
Form/State a Hypothesis An educated guess a prediction Use If, then format If is the independent variable or the manipulated variable. Then is the dependent or responding variable. Example: We predict that if we drop a ball from a higher height, then it will bounce higher.
Testing a Hypothesis Experiment, Experiment, Experiment! Build a Model
Key Idea When conducting an experiment, change one factor and keep everything else exactly the same. The one thing you change is called the independent variable. All the things you keep the same are called constants. A control is the standard by which the test results can be compared. It does not receive the independent variable!
Galileo s Experiment 1. What was the independent variable in Galileo s experiment? The weight of the balls. 2. What was the dependent variable? The time it took to fall to the ground. 3. What were some constants? Dropped from same height. Dropped at same time. Balls had same shape/size.