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 Information gathered by the “Scientific Method”

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: Why is there little ground vegetation in this forest? 2nd step: Create a hypothesis If…then statement Example: If there are tall trees blocking sunlight, then few plants will grow near the ground.

3rd step: Design an Experiment Experiments test the independent variable Independent variable: factor altered Two parts to an experiment Control group: comparison group Ex: patch of forest with the large trees 2) Experimental group: contains the independent variable Ex: patch of land w/o canopy trees Data collected is called the dependent variable Ex: growth height of the plants

Here is a well designed setup

Control Group Experimental Group 8cm rain/month 8cm rain/month 6 hours sun/day 6 hours sun/day Grazing animals 60⁰ temp 60⁰ temp Grazing animals Large canopy trees Patch of open land The experimental plants grew 1 meter taller. What most likely caused this change?

Here is a poorly designed setup

Unknown! Too many changed variables! Control Group Experimental Group 8cm rain/month 8cm rain/month 6 hours sun/day 4 hours sun/day Grazing animals 60⁰ temp 80⁰ temp Grazing animals Large canopy trees Patch of open land The experimental plants grew 1 meter taller. What most likely caused this change? Unknown! Too many changed variables!

4th Step: Data Analysis Collect data to either support/reject your hypothesis Ex: Plants on the ground grew almost 1m taller w/o the canopy trees 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

Farmer Bob wants to test his 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 but adds no fertilizer. In section B, he waters his crops as usual and also adds his 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 Substance added to the crops 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

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

Kobe Kuiz 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?