Scientific Method

Going on a trip… Throw all your clothes in a suitcase or plan what you are going to wear?

Scientific Method An organized process used by scientists to do research

Using our senses to gather information Observation Using our senses to gather information This might seem pretty obvious, but throughout history, many educated men and women rejected the idea that you could understand the world simply by looking at it. “If our goal is to learn about the world, then the first thing we must do is look around us and see what’s there”

How many teeth does a horse have? Someone quoted Aristotle Someone quoted St. Augustine Young monk noted since there was a horse outside they could look in its mouth “Fell upon him, smote him hip and thigh, and cast him from the presence of educated men”

Observation Qualitative Data – info that describes color, odor, shape, or other physical characteristics Quantitative Data – Uses numbers

Qualitative and Quantitative Data?

Pose a question, missing information Problem Pose a question, missing information Why? What? How?

a tentative educated guess Hypothesis a tentative educated guess Means nothing unless there is data to support it!!!

Forming Hypothesis Look for patterns that will help you make predictions about the problem Break the problem down into smaller, simpler problems Must be testable

A Scientific Hypothesis The moon is made of cheese. The alignment of planets in the sky determines the best time for making decisions. Intelligent life exists on planets somewhere in the universe besides Earth. 1 – can be proven right or wrong by going there 2 – can’t be proven right or wrong, subjective 3 – can be proven right but not wrong All hypothesis’s must be able to be proven wrong!

predict consequences that can be observed if the hypothesis is correct Predictions predict consequences that can be observed if the hypothesis is correct If… Then…

Test predictions do experiments to see if consequences you predicted are present

Aristotle’s Hypothesis (384-322 B.C.) Claimed heavy objects naturally fall faster than light objects Believed for nearly 2000 years! Everyone respected him as a great thinker so he must be right, and people had seen stones fall faster than leaves. Without investigating further, it is easy to believe false ideas

Galileo’s Experiment Studied Aristotle’s hypothesis HE EXPERIMENTED!

experiments Do them over and over! The more trials you perform the more accurate your results are

Was your hypothesis right or wrong? Draw Conclusion Make a judgment based on the information obtained Was your hypothesis right or wrong?

Watch out for biases! Accept their experimental findings even when they would like them to be different Mistakes or deceptions are sooner or later found out!

Failure! What if you are wrong? “I didn't fail, I found 2,000 ways how not to make a light bulb; I only need to find one way to make it work.”

A hypothesis can never be proven! If data supports it, it only indicates that it might be true

An investigation of Sea Butterflies Study of toxic chemicals released by marine life to deter predators Observation: Many Amphipods carried sea butterflies on their backs. If they lost one they would quickly find another one.

An investigation of Sea Butterflies Question: those carrying sea butterflies were slowed down, so why did the amphipods abduct the sea butterflies?

An investigation of Sea Butterflies Hypothesis: amphipods carry sea butterflies to produce a chemical that deters a predator of the amphipod.

An investigation of Sea Butterflies Prediction: they would isolate this chemical and an amphipod predator would be deterred by it

An investigation of Sea Butterflies Test Predictions: Predator fish rejected sea butterfly Predator fish ate amphipod Predator fish rejected amphipod with sea butterfly

An investigation of Sea Butterflies Conclusion: results expected if sea butterfly was secreting a chemical, but could also be that fish don’t like the feel of sea butterfly so conclusion couldn’t be drawn yet

An investigation of Sea Butterflies So now what?

An investigation of Sea Butterflies Test Predictions: Predator fish ate fish meal pellets Predator fish rejected pellets containing sea butterfly extract

An investigation of Sea Butterflies Conclusion: after many experiments with extracting chemicals, they were finally able to conclude that the secretion of pteroenone was being used by the amphipods to deter their predators