The Scientific Method

What is Science? Science: Process that produces information about nature Steps: Observation & Experimentation Why: Apply the results to the real world Why: Better understand our world

Scientific Method Defined: Series of steps to collect information or solve problems 1) Observation 2) Hypothesis 3) Experimentation 4) Data Analysis 5) Conclusion

Observation and Hypothesis 1st step: Make an observation Example: I seem to sleep better when I play relaxing music. 2nd step: Create a hypothesis If…then statement Example: If there is relaxing music playing, then I will sleep longer.

3rd step: Design an Experiment Two parts to an experiment Control group Receives no special treatments Used as comparison 2) Experimental Group Same as control group, except…the independent variable Independent variable = one factor that differs from the control group Dependent variable: Data measured

Here is a well designed setup

Did the music cause the extra sleep? Control Group Experimental Group Curtains closed Curtains closed Soft bed Soft bed Usual exercise Healthy meals Usual exercise Healthy meals No music while sleeping Music while sleeping Test for 1 month Test for 1 month Did the music cause the extra sleep? Average 6.2 hours sleep Yes. It was the only reason to explain the extra sleep. Average 7.5 hours sleep

Control Group Experimental Group Average 6.2 hours sleep Curtains closed Curtains closed Soft bed Soft bed Usual exercise Healthy meals Usual exercise Healthy meals No music while sleeping Music while sleeping Test for 1 month Test for 1 month 30 seconds to discuss with your neighbor. What’s the independent variable? What’s the dependent variable? Average 6.2 hours sleep Average 7.5 hours sleep Presence of music Amount of sleep

Here is a poorly designed setup

Did the music cause the extra sleep? Control Group Experimental Group Curtains closed Soft bed Soft bed Curtains open Increased exercise Usual exercise Healthy meals Healthy meals No music while sleeping Music while sleeping Test for 1 month Test for 1 month Did the music cause the extra sleep? Average 6.2 hours sleep Average 7.5 hours sleep Unknown. Extra sleep could have been due to other variables.

A teacher wants to know if her new teaching method is more successful than traditional teaching methods. She compares test scores of her period 2 class (received the traditional teaching method) verses her period 4 class (received new teaching method). Each class has a random mix of honors students. Period 2 students Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Period 4 students Teaching method Test scores

A high school soccer team on average scores 2 A high school soccer team on average scores 2.2 goals per game by practicing 4 days a week. The coach wants to see if practicing 5 days a week will help the team score more goals. The coach has the team practice 5 days per week and compares the goals scored per game. Practicing 4 days per week Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Practicing 5 days per week Length of practice Goals scored per game

The city of Los Angeles wants to know if there is a connection between physical fitness and air pollution. Fifty volunteers from the mayor’s office agree to be tested. First, they are asked to ride a stationary bike for 1 hour in a pollution-free air chamber. A week later, the 50 volunteers return and are again asked to ride a stationary bike for 1 hour in a chamber filled with air pollutants common to Los Angeles. Their heart rates are monitored throughout the 1 hour bike rides. Volunteers who breathed common polluted air Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Volunteers who breathed clean air Quality of air breathed Heart rates

Farmer Bob wants to test a new fertilizer to help his crops grow better. He sections off two large areas of his field. In section A, he waters his crops as usual and uses his normal fertilizer. In section B, he waters his crops as usual and but adds the experimental fertilizer. After 1 growing season, he records the growth of the crops. Section A Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Section B Type of fertilizer used Growth of the crops

The United States military wants to see if soldiers with only 4 hours of sleep can operate at the same level as those who normally get 7 hours of sleep. One hundred solders are allowed to only sleep for 4 hours a night and another hundred are allowed to sleep for 7 hours a night. During the day, the soldiers are tested for marksmanship on the firing range. . . . Soldiers with 7 hours sleep Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Soldiers with 4 hours sleep Amount of sleep given Score on the firing range

4th Step: Data Analysis Without music With music Collect data to either support/reject your hypothesis No hypothesis is proven after 1 experiment

5th Step: Conclusion Your findings could be shared and repeated by others Theory develops over time Theory = long standing hypothesis Theories and hypotheses change based on new information

Recap Place the 5 steps of the scientific method in order from start to finish. Data analysis, Observation, Conclusion, Experimentation, Hypothesis In which stage of the scientific method are graphs usually created? In which stage of the scientific method are the two variables identified? Which variable is the difference between the control and experimental group? Which group of an experiment is used for comparison and contains no changes? How many independent variables should exist in a well designed experiment? What is the data collected from the independent variable called? Vocabulary: Science, Scientific method, Hypothesis, Control group, Experimental group, Independent variable, Dependent variable, Theory