Introduction to Our Planet © Lisa Michalek

Earth Science The study of our planet, systems, and setting in the universe. What will we study this year? Planet Earth Minerals, Rocks, and Resources The Earth’s Crust Weathering, Erosion, Deposition, and Landscapes Earth’s History The Atmosphere Weather Systems The Water Cycle and Climates Earth in Space Beyond Planet Earth Environmental Awareness

The Methods of Science The technique used by scientists to solve problems is known as the scientific method. The scientific method solves problems in a logical and organized way.

Steps of the Scientific Method State the Problem The problem is a question for which the scientist is trying to find an answer. Propose a Hypothesis A hypothesis is an educated guess about the possible answer to the problem.

Steps of the Scientific Method Test the Hypothesis The scientist must design an experiment that will test the hypothesis. The experiment, called a controlled experiment, should test only one factor. The factor to be tested is called the variable. Another experiment that is the same in every way but does not contain the variable is called the control.

Steps of the Scientific Method Make Observations From the experiment, the scientist makes observations that are recorded in an organized manner. These observations include careful measurements, as well as observations made with the senses and with instruments. From these observations, a conclusion about the problem is reached.

Steps of the Scientific Method State a Conclusion The answer to the problem is called the conclusion. To be valid or true, the conclusion must be backed up by facts called data. These facts result from observation and experimentation. Repeat the Experiment The experiment is repeated many times to check the conclusions. When, after repeated testing, many scientists reach the same conclusion, the conclusion may be called a scientific law.

Steps of the Scientific Method

Scientific Method Example You arrive home late at night, walk up to your house door, unlock the door, and reach in to the light switch just inside the front door. The light does not come on! Now what? As a normal human being, you will go through a mental and physical process of hypothesis testing. The steps happen very rapidly in your mind and, prior to this, you may not have had names for the various steps. Nevertheless, I hope you will recognize what your brain is doing as you stand there in the darkness. You are already a scientist, as you will see, you just didn't know it!

Scientific Method Example Observation: Night, Come Home, Switch On, No Light....we are "IN THE DARK" Question: Power Out? Hypothesis: Power IS out! Prediction: If power is out then, the lights are out at all neighbors Experiment: Manipulation: switch on, no light Control = neighbor's lights, street lights

Scientific Method Example Analysis: If ANY house with light, prediction fails, decision = reject? error? Coleman Lantern, Generator If all houses dark, prediction holds, decision = not reject? Error? All out to dinner, movies, fireworks? Decision: above, note chance error = no definitive answer...NO PROOF!

Scientific Method Example Question: Switch broken? Hypothesis: Switch IS broken Prediction: If hypothesis is true, then brief flash, when I jiggle switch Experiment: jiggle switch...not even a flash Analysis: Too broken to even flash? needs stronger test, replace switch? Do switches fail frequently? Maybe another hypothesis is more likely? Abort...no electrical work in the dark!

Scientific Method Example Question: Light bulb burned out? Hypothesis: Light bulb IS burned out! Prediction: If hypothesis true, then light will come on, when I install new bulb Experiment: Grope in closet in dark or rob another lamp...install bulb...LIGHT! Analysis: Original bulb would not light, new bulb does light Decision: Cannot reject hypothesis! Error: NO PROOF...more testing needed!

Scientific Method Example Prediction: If hypothesis true, then bulb will tinkle, when I shake it Experiment: Shake it, control is new bulb Analysis: No tinkling! Decision: Reject hypothesis! NOW WE ARE CONFUSED! More testing! Error: wire not broken or wire broken in only one place (no tinkle!)

Scientific Method Example Question: Bulb loose in socket? Hypothesis: Bulb was loose Prediction: If hypothesis true, then light will come on, when I re-install it Experiment: Tighten it...It lights! Analysis: Can we be sure that it was loose? Decision: Cannot reject.....NO PROOF! Error: maybe power just came back on... switch is weirdly intermittent...