VARIABLES INDEPENDENT VARIABLES DEPENDENT VARIABLES CONTROLLED EXPERIMENTS Analyzing Experiments

What is the Problem? First step in the scientific method Establishes purpose Based on observations Stated as a question

Why Research? Learn more about the topic Pick out key words in the problem question Helps to make an educated hypothesis Gives insight into materials that may be needed Use internet, books, scientific magazines and articles, scientific journals, scientists/teachers, interviews, prior knowledge

What is a Hypothesis? Is not an opinion Is not a question. It is a statement. Is based on research and observations Must be testable. It is okay if it turns out to be wrong/unsupported by data collected in experiment.

What is an Experiment? A way to test your hypothesis Allows you to gather data to make conclusions Contains more than one trial Contains variables:  Controlled variables  Independent (Manipulated) variables  Dependant (Responding) variables

Ball Drop Experiment Problem: Will two balls of different masses fall at the same rate? Research: Gravity will cause any thrown or dropped ball to fall to the ground. Hypothesis: Galileo said that objects of different masses fall at the same rate and will therefore hit the ground at the same time (ignoring air resistance). Experiment: Drop two balls of different masses off of a table. Observe to see if they hit the ground at the same time.

What is a variable? Anything that a scientist can change in an experiment What are some variables in the Ball Drop Experiment?  The mass of the ball  The size of the ball  The weight of the ball  The distance it falls  The height of the table  Who drops the ball

What is a Independent Variable? The one variable that is purposely changed Also called manipulated variable What should be the manipulated variable in the Ball Drop Experiment?  The mass/type of ball

What is a Dependent Variable? Also called the responding variable The factor that MAY change in “response” to the manipulated variable It “depends” on what was changed What is the Dependent variable in the Ball Drop Experiment?  When it hit the floor/ time it takes to hit the floor

What is a Controlled Experiment? An experiment in which only one variable is manipulated at a time. That means only the manipulated variable changes and every other variable stays the same. What are some variables we need to “control” in the Ball Drop Experiment?  The size of the ball  The distance it falls  The height of the table  Who drops the ball

Analyze the Results Organize data from experiment into charts, tables, and graphs Look for trends and/or patterns Identify discrepancies Supports claims in conclusions

How do I make Conclusions? Return to your problem question and try to supply some answer. (even if the answer is: “I still do not have an answer.”) Summarize findings Return to your hypothesis and compare your experiment results to your hypothesis. Are they the same or different? Why do you think? Make conjectures and support them with your data Explain why your findings are important. How might they help others? Discuss possible problems with the experiment. How could it be improved? Discuss future experimentation that may help you answer your question Present new questions your experimentation results may have unfolded

Drawing Conclusions Mary went downstairs. There was an aroma in the air. The table was set with warm blueberry muffins, freshly squeezed orange juice, and brewed coffee. A note was left on the table. It said, "Dear Mary, Have a great day. Good Luck at your new job. Love, Dan" Next to the note there was a wrapped present with a bow on top. Who is Mary? A: a wife B: a husband C: a baker D: a nice person

Drawing Conclusions Mary went downstairs. There was an aroma in the air. The table was set with warm blueberry muffins, freshly squeezed orange juice, and brewed coffee. A note was left on the table. It said, "Dear Mary, Have a great day. Good Luck at your new job. Love, Dan" Next to the note there was a wrapped present with a bow on top. What time of day is it? A: morning B: afternoon C: evening

Drawing Conclusions Mary went downstairs. There was an aroma in the air. The table was set with warm blueberry muffins, freshly squeezed orange juice, and brewed coffee. A note was left on the table. It said, "Dear Mary, Have a great day. Good Luck at your new job. Love, Dan" Next to the note there was a wrapped present with a bow on top. What was the purpose of the note? A: to inform B: to entertain C: to congratulate D: to thank

Drawing Conclusions Mary went downstairs. There was an aroma in the air. The table was set with warm blueberry muffins, freshly squeezed orange juice, and brewed coffee. A note was left on the table. It said, "Dear Mary, Have a great day. Good Luck at your new job. Love, Dan" Next to the note there was a wrapped present with a bow on top. Who is Dan? A: her husband B: her boss C: her neighbor

Drawing Conclusions Mary went downstairs. There was an aroma in the air. The table was set with warm blueberry muffins, freshly squeezed orange juice, and brewed coffee. A note was left on the table. It said, "Dear Mary, Have a great day. Good Luck at your new job. Love, Dan" Next to the note there was a wrapped present with a bow on top. What is Mary's new job? A: store clerk B: baker C: real estate agent D: not enough information given

Drawing Conclusions Mary went downstairs. There was an aroma in the air. The table was set with warm blueberry muffins, freshly squeezed orange juice, and brewed coffee. A note was left on the table. It said, "Dear Mary, Have a great day. Good Luck at your new job. Love, Dan" Next to the note there was a wrapped present with a bow on top. Who probably made the muffins, orange juice, and, coffee? A: Mary B: Dan

Drawing Conclusions Mary went downstairs. There was an aroma in the air. The table was set with warm blueberry muffins, freshly squeezed orange juice, and brewed coffee. A note was left on the table. It said, "Dear Mary, Have a great day. Good Luck at your new job. Love, Dan" Next to the note there was a wrapped present with a bow on top. Why was there a present on the table? A: to congratulate B: a thank you gift C: to say sorry D: not enough information given

Drawing Conclusions Miss Amole is always trying to save money, but she also likes a quality product. She decided to do an experiment to see if the “cheap” paper towels were just as strong as the “expensive” ones. She bought two types of paper towels: Brawny (expensive) and Bounty (cheap). Miss Amole thought the Brawny paper towels would be stronger since they were more expensive. She placed both paper towels in a bowel that contained the same amount of water. After soaking for one minute, Miss Amole rung both paper towels out as best she could and unwrinkled them. She then placed a soup can on the paper towels and observed how long the paper towels could hold the can before tearing. The Bounty held for 20 seconds and the Brawny held for 5 seconds. What conclusions can we make?

Drawing Conclusions The graph below shows the relationship between maternal age and the incidence of children born with Down syndrome (a condition that results in an individual having an extra chromosome 21). What conclusion is best supported by the data? A. There is no risk of Down syndrome in children born to mothers under age 34. B. The risk of Down syndrome increases dramatically in children born to mothers after age 34. C. The risk of Down syndrome doubles in children born to mothers for each year over the age of 34. D. There is no correlation between the number of Down syndrome births and age.

Drawing Conclusions Environmental monitoring of a lake located to the southeast of a factory has shown a consistent decrease in pH over the period of a year. A researcher investigating the pH change hypothesizes that either a factory or a farm along the river is responsible for the pH change. The river flows into the lake. The researcher collects a water sample from locations Y and Z in the diagram and runs pH analyses on each sample. He finds that the pH in sample Z is lower than the pH in sample Y and concludes that the factory is responsible for the low pH values in the lake. Based on the diagram and the researcher’s investigation, provide two reasons why this may not be a valid conclusion. Describe how each reason could invalidate the conclusion.