Scientific Method

Initial Observation Use your senses to observe -be objective (measure), not subjective (opinions) –See, hear, touch, taste, smell, etc. Can also use tools to measure (label numbers) –Temperature, length, volume, etc.

Which is the better observation? It is 58 o F in the room. It is cool in the room. The iguana likes lettuce. The iguana consumed 90% of the lettuce. The bacteria is yucky. The bacteria has a slimy appearance and smells of sulfur.

State the Question “What is the effect of _____ on ____.”

Hypothesis “If…then…” If producing oxygen bubbles in photosynthesis is related to light color, then green light will increase photosynthesis oxygen bubbles to form. Dependent variable Independent variable prediction

Hypothesis 1. Must be testable – some way to check its validity 2. Must be falsifiable – must be some experiment that could show that it is not true (may not prove to be false, just have to be able to test that)

Can you test these to be falsifiable? 1. Animals are better than plants. 2. The average tree height on the HS campus is the same as on the MS campus. 3. How many angels does it take to dance on the head of a pin? 4.

DO WORKSHEET TO PRACTICE WRITING IF…THEN HYPOTHESES

Experiment A. Independent Variable -what you change goes on the X-axis of the graph B. Dependent Variable -what changes as a result of what you did – goes on the Y-axis of the graph

Independent Variable? Dependent Variable?

Experiment Constants-all the things in the experiment that stay the same same size Petri dishes Same agar medium Same type of bacteria

What constants are there in this experiment?

Control – the part of the experiment that does not have the independent variable in it Use for reference, comparison Often the normal condition

L-added oxygen M-control(no gas added) R-added carbon dioxide

What is the control set-up?

Do you think a placebo is a control? (inert pill, one without the drug) EX: some take Celebrex®, some take a sugar pill

Run the tests Record the data graphs charts video write observations measurements

Celebrex – Placebo Experiment Results Have we proven that Celebrex® (without a doubt) improves arthritis pain? What might be another explanation? Can we prove it false? Placebo

Conclusion Agree or disagree with the hypothesis The 10% spray produced taller plants.

Repeat the Experiments Other scientists must be able to repeat your experiment with similar results to prove it true. OR they might prove it false.

NOW YOU WILL DESIGN AND RUN AN EXPERIMENT RECEIVE HANDOUT CHOOSE GROUPS OF 4 DECIDE VARIABLE -HAVE IT APPROVED PLAN SET-UP RUN 3 TRIALS WRITE RESULTS