(Experimenting Terms) How to Design an Experiment (Experimenting Terms)

It is an organized procedure for TESTING a hypothesis. What is an Experiment? It is an organized procedure for TESTING a hypothesis. A process in which you test to see how one thing affects another thing.

It is much more than just an educated GUESS. What is a hypothesis? It is a possible explanation for a problem based on what is known and observed. It is much more than just an educated GUESS. Your Hypothesis must be supported with logical thinking..

Independent Variable? What is the It is the factor in an experiment that is changed on purpose to see how it affects something else. If you are having a hard time identifying the Independent Variable in an experiment, just put yourself in the role of the scientist that did the experiment and say, “The Independent Variable is the factor that I changed.”

What are Levels of Independent Variable? The levels are simply the number of different changes that you will try. EVERY experiment must have a minimum of TWO levels: (1)The First level should be the Controlled level (2)The second and beyond should be the Change(s) being tested

What is the Dependent Variable? It is the factor in an experiment that is expected to change only after the scientist changes the Independent Variable. This is the part of the experiment that you are Measuring. So this means that it must be something that CAN BE measured.

What are Constants? Factors in an experiment that Do NOT change from one level to the next. You are to ONLY change the Independent Variable and NOTHING ELSE!. If you change more than one thing there is no way to tell what factor caused the change.

ALL Data from the other levels are compared to the control data. What is the Control? It is the level of the experiment where the scientist DOES NOT introduce a change. This level of the experiment is considered to be what would happen under “Normal” conditions. ALL Data from the other levels are compared to the control data.

Number of Trials? Why do a Repeating the experiment more than once for each level of the experiment will make the DATA more reliable. The results of the trials should be averaged together to eliminate possible errors of data collection process.

Here’s an Example Retired professional soccer player, Landon Donovan wonders and then asks the following question: “How does the air pressure of a soccer ball affect the distance it can be kicked?”

The ball’s air pressure After doing some research, Landon decides to test the following Hypothesis: If a soccer ball’s air pressure is increased, then the kicked distance of the ball will also increase… What is the Independent Variable of his experiment? Because, research shows that more air will cause a soft object to become more firm which increase the affects of Newton’s 3rd law. The ball’s air pressure What is the Dependent Variable of his experiment (What is he measuring)? The distance kicked

He will test the following Levels of Independent Variable Official PSI 8.7 PSI Level 2: Slightly higher PSI 9.0 PSI Level 3: Slightly lower PSI 8.0 PSI Level 4: Extremely higher PSI 15.0 PSI Level 5: Extremely lower PSI 2.4 PSI

He will run all five levels the same way All test will take place in an indoor area. What will stay constant because of this testing location? After watching a YouTube video, he decides to build and use a machine to provide a consistent force to each ball Kicking Machine Blueprints

He collects the following DATA Level Trial 1 Trial 2 Trial 3 Average  8.7 PSI 5.0000 m 5.1000 m 4.9000 m  9.0 PSI 5.5000 m 5.7000 m 5.9000 m  8 PSI 4.2000 m 4.8000 m 4.5000 m 15 PSI 6.0000 m 6.2000 m 5.8000 m  2.4 PSI 0.2000 m Which Level Represents the Control? Level 1 – 8.7 PSI Because it is at “Normal” PSI