Experimental Design Review Use this information as a study tool.

Experimental Design Vocabulary Hidden Variable Any constant that changes unexpectedly during an experiment Level The degree to which the independent variable is changed Repeated Trials Repeating the experiment over and over again, at least 3 trials

Homework 8.24.07 Study your notes for the short test on Friday Read “Refining Experiments” Complete the Anticipation Guide We will use the Anticipation Guide to review before taking the test on Friday. You will begin a lab write up on “The Great Tomato Race.” This lab will be due on “8-30-07.” It will be worth 150 points. Most of it requires you to cut an paste information from the “Experimental Design Ditto into your Journal” Follow the guidelines for “Keeping a Scientific Journal”

Starter: Analyzing Data 8.23.07 Temperature of the Ketchup The Average speed of the Ketchup 2nd 3rd 4th 6th 7th Average Temperature Hot Cold Room There are three levels of change in this experiment. What are they? If you look at the first level of change, you will notice that the average data for each class period is different. Why do you think the data for each class period or group looks different?

Oops: We made a few mistakes Used different brands of ketchup Recorded data in inches instead of centimeters Shook the paper plates Allowed the ketchup to flow for more than 30 seconds Forgot to record all of our data Used room temperature water instead of hot water Forgot to read the directions very carefully Measured incorrectly

Another Variable Even though some scientists perform the same experiments, they, often, don’t get the same results as other scientists. Although their data may look different, they probably notice that the trend or pattern is similar. The difference in the recorded data could have created a margin of error known as a hidden variable. A hidden variable is a constant that changed unexpectedly. Sometimes, these hidden variables can really mess up an experiment.

Hidden Variables in the Great Tomato Race The temperature The same number of ice cubes Did we check to see if the temperature of all three levels were the same for each group? Did we really tilt the plate at a 45 degree angle? Do you think this changed the way that our data looked?

Experimental Design Vocabulary Hidden Variable Any constant that changes unexpectedly during an experiment Level The degree to which the independent variable is changed Repeated Trials Repeating the experiment over and over again, at least 3 trials

Homework Complete the “Before Reading” column of the “Refining Experiments” anticipation guide. Read about “Refining Experiments” pages 9-11. Complete the “Refining Experiments” Cornell Notes Complete the “After Reading” column of

Experimental Design Vocabulary Starter: 8.23.07 (Page 6) Question is the ___________ you are trying to solve in an experiment __________ is the predicted answer to the problem __________ is a factor in the experiment that is changing _____________ is the one factor that the experimenter changed on purpose _____________ is the one factor that the experiment did not change on purpose, but can see changing and will measure it somehow ____________ is all of the factors that are kept constant in an experiment ____________ is the degree to which the independent variable is changed Repeated Trials consist of repeating the experiment over and over again, at least 3 trials

More Vocabulary ______________ is observation data, usually gathered by using your 5 senses. ______________ is numerical data usually gathered by either counting or measuring. Line graphs show a direct relationship between the independent and dependent variable in an experiment. Analysis or to analyze means to interpret the data A ____________ is your final thought or answer in an experiment.

Experimental Design Vocabulary Starter: 8.23.07 (Page 6) Question is the problem you are trying to solve in an experiment Hypothesis is the predicted answer to the problem Variable is a factor in the experiment that is changing Independent Variable is the one factor that the experimenter changed on purpose Dependent Variable is the one factor that the experiment did not change on purpose, but can see changing and will measure it somehow Constant is all of the factors that are kept constant in an experiment Hidden Variable is any constant that changes unexpectedly during an experiment Level of change is the degree to which the independent variable is changed Repeated Trials consist of repeating the experiment over and over again, at least 3 trials

More Vocabulary Qualitative Data is observation data, usually gathered by using your 5 senses. Quantitative Data is numerical data usually gathered by either counting or measuring. Line graphs show a direct relationship between the independent and dependent variable in an experiment. Bar graphs show an indirect relationship between the independent and dependent variable in an experiment. Analysis or to analyze means to interpret the data A conclusion is your final thought or answer in an experiment. A theory is a well-test explanation (Big Bang Theory) A scientific law describes a reoccurring pattern in nature