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 Observe the living world –Example: Very little plant life on forest floor Hypothesis: tentative explanation –If…then statement –Example: If there are tall canopy trees blocking sunlight, then few plants will grow near the ground.

Experimentation Designed to test independent variable Independent variable: factor altered Ex: Presence of canopy trees Two parts to an experiment 1) Control group: comparison group Ex: patch of land with large canopy trees 2) Experimental group: tests the independent variable Ex: patch of land w/o canopy trees Dependent variable: data collected Ex: growth height of the plants

Here is a well designed setup

Control GroupExperimental Group 6 hours sun/day 8cm rain/month Grazing animals 60 ⁰ temp Large canopy treesPatch of open land The experimental plants grew 1 meter taller. What most likely caused this change?

Here is a poorly designed setup

Control GroupExperimental Group 6 hours sun/day 4 hours sun/day 8cm rain/month Grazing animals 60 ⁰ temp 80 ⁰ temp Large canopy treesPatch of open land The experimental plants grew 1 meter taller. What most likely caused this change? Unknown! Too many changed variables!

Data Collection Collect data to either support/not support your hypothesis –No hypotheses are proven after 1 experiment Data and Results: Plants on the ground grew almost 1m taller w/o the canopy trees

Conclusion & Repetition Your findings would be shared and duplicated by others Develop a THEORY (hypothesis that has been tested and continually supported) 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. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Section A Section B Chemical 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. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Soldiers with 7 hours sleep Soldiers with 4 hours sleep Amount of sleep given Score on the firing range

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. Name the control group _________________________________________________ Name the experimental group ____________________________________________ Name the independent variable __________________________________________ Name the dependent variable ____________________________________________ Volunteers who breathed common polluted air Volunteers who breathed clean air Quality of air breathed Heart rates

Quick Review Science tries to explain the natural world Science is made through observation and experimentation Science is continually changing based on new information