What is Science? Identify 3 ways in which science affects your life?

Science To investigate and understand the natural world (meaning what?) To explain events in the natural world To use those explanations to make useful predictions Other ideas/def: The pursuit of knowledge and/or the body of knowledge already accumulated

How do we test our knowledge? Scientific Method 1.Observations 2. Inferences from data 3. Hypothesis ( if…then statement) 4. Create controlled experiment 5. Analyze Data Collected 6. Make Conclusion **Theory- well tested explanation that unifies a broad range of observations

Controlled Experiment A hypothesis should be tested by an experiment in which only one variable is changed at a time All other variables should be kept unchanged, or controlled. SAMPLE EXPERIMENT: What are some variables that affect plant growth?

Control Group vs. Experimental Group Control Group: Needed for comparison Experiment is invalid without it All factors remain the same= Controlled Variables Experimental Group: All factors remain the same EXCEPT for one that you change= Manipulated Variable

The Outcome All results must be measurable The variable that is observed and measured that changes in response to the manipulated variable: RESPONDING VARIABLE

Identify manipulated, responding, and controlled variables Students were testing the effect of caffeine on soybean seed growth. Sixteen 8-ounce pots were used. One soybean seed was planted into each pot. Upon the initial sowing of the seeds, all sixteen pots were watered and fertilized. All pots were kept under artificial light for 12 hours per day at a constant temperature of 72 degrees. Eight of the soybeans received 20mL of a caffeine solution of set concentration. The caffeine solution consisted of caffeine powder dissolved in distilled water. Growth in cm was recorded daily for 4 weeks.