Warm Up #1 The active ingredients in many pesticides are chemical compounds that kill organisms such as insects, molds, and weeds. They can also have unintended consequences… Design a laboratory experiment to determine whether or not a new pesticide (product X) is toxic to minnows, a type of small fish. Include the hypothesis, how you would test it, a control and an independent variable

Scientific Method

Scientific Method Step 1: OBSERVATIONS Things that you notice Example: Many pesticides being used are killing organisms other than the intended pests (such as minnows)

Scientific Method Step 2: HYPOTHESIS Educated guess based on observations If/Then statement OR a Declarative statement Example: If Product X is added to water, then it will be toxic to fish OR Product X is toxic to fish when added to water.

Scientific Method 2 Major Groups CONTROL GROUP EXPERIMENTAL GROUP Remains constant, serves as baseline Tank WITHOUT product X Others controls: Amount of water Amount of fish in each tank Temp/light conditions Group being tested Concentration of Product X in tank INDEPENDENT VARIABLE – something YOU are manipulating/changing Mortality rate of minnows DEPENDENT VARIABLE – EFFECTS of independent variable manipulation

Scientific Method To Have GOOD Results: Multiple Trails (ensures PRECISION – same results each time) Large Population Size (ensures ACCURACY – no skewed data) Multiple Experimental Groups (varying concentration levels of Product X)

Multiple Experimental Groups TANK 1: NO PRODUCT X TANK 1: MEDIUM PRODUCT X CONCENTRATION TANK 1: HIGH PRODUCT X CONCENTRATION TANK 1: LOW PRODUCT X CONCENTRATION

Quick Quiz #1 How does an independent variable differ from a dependent variable? Describe experimental results that would lead you to reject your hypothesis in part (a). (Be specific.)