Prior to the Scientific Method: Philosophers such as Aristotle tried to explain their observations of the world though reasoning They thought that special “vital” forces brought some living things into being from non-living things Recipe for Bees: Kill a bull during the first thaw of winter. 2. Build a shed. 3. Place the dead bull on branches & herbs inside the shed. 4. Wait for summer. The decaying body of the bull will produce bees.

SPONTANEOUS GENERATION Spontaneous Generation: Life from non-life Idea was accepted for centuries Ex: Maggots are formed from meat; mice from grain; beetles from cow dung In the late 1700s through the mid 1800s many scientists designed experiments to disprove this idea In 1864 Louis Pasteur changed the way people thought about life by showing that all living things come from other living things!

THE SCIENTIFIC METHOD

If scientific facts may not be true after all, why learn them? Science is not a collection of “truths.” It is a process and a way of looking at the world around us. Science explains the world today, based on research and evidence we have collected so far.

Observation vs. Inference Be careful with your observations! Observation: use of one or more of the senses to gather information Ex: I see 3 fish at the edge of the lake. My plant looks wilted Inference: A conclusion or interpretation drawn from observation and prior knowledge Ex: This lake is filled with fish! My plant needs water http://www.michaelbach.de/ot/mot_adaptSpiral/index.html

Hypothesis Definition: possible explanation for a set of observations Useful only if it can be tested! Arise from prior knowledge, logical inferences, or imaginative guesses A hypothesis always has value whether right or wrong!

What is a Theory? When a hypothesis is tested and confirmed often enough that it is unlikely to be disproved by future tests Theory: All well tested set of explanations that unifies many observations A theory is the highest form of knowing As we continue to learn theories are refined and modified to better explain our deeper understanding Science is a PROCESS

Scientific Method Observation: use senses leads to a question Gather data from more observations Qualitative: characteristics (ex: red hair) Quantitative: numbers (ex: plant height= 32cm) or Form a Hypothesis using Prior Knowledge and data Test Hypothesis by research & sometimes experiments Record & Analyze Data (charts & graphs) Form a Conclusion based on evidence, and new questions