The Nature of Science

1-1 What is Science?

1-2 The Scientific Method

Fossil in the Butte

• In the southwest corner of Wyoming, there is a flat-topped mountain called Fossil Butte. A fossil of a fish was found near the top of Fossil Butte in a rock formation that is about 50 million years old. Fossils of other kinds of fishes, as well as turtles, have been found at Fossil Butte. The land around Fossil Butte is dry, and the Pacific Ocean is more than 1000 km away. How could fossils of sea-dwelling animals have formed at Fossil Butte?

Yum Yum

• You left out an apple on your table.

• After 5 days, the apple decays and you notice little worms coming out of the apple.

• Hmmm… how did the worms get there?

Worms and apples

• Prior knowledge– What do you know about worms and apples?

• What did you observe?– Qualitative– Quantitative

• What do you infer?

• How can you come up with an experiment?

Designing an ExperimentSection 1-2

Flowchart

Go to Section:

State the Problem

Form a Hypothesis

Set Up a Controlled Experiment

Record Results

Analyze Results

Draw a Conclusion

Publish Results

Control versus Variable

• Conduct two ALMOST identical experiments

• Control– Item that is the SAME in BOTH experiments

• Variable– Item that is the DIFFERENT in BOTH

experiments

In any experiment

• Is it better to have fewer controls or fewer variables?

• Less variables more control

Steps of the Scientific Method

1. Observing and stating the problem– You have to notice it before you think about it

2. Form a hypothesis– Take a guess to explain it

3. Test the hypothesis– Create an experiment with controls and variables

4. Record and analyze data

5. Form conclusion– Does you data backup your hypothesis?

6. Replicate the work– Can you do it again and get the same conclusion?

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.PROCEDURE

Controlled Variables:jars, type of meat,location, temperature,time

Manipulated Variables:gauze covering thatkeeps flies away from meat

Uncovered jars Covered jars

Several days pass

Maggots appear No maggots appearResponding Variable: whether maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Section 1-2

Figure 1-8 Redi’s Experiment on Spontaneous Generation

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Gravy is boiled. Flask isopen.

Gravy is teeming with microorganisms.

Gravy is boiled. Flask issealed.

Gravy is free of microorganisms.

Section 1-2

Figure 1-10 Spallanzani’s Experiment

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Broth is boiled. Broth is free ofmicroorganismsfor a year.

Curved neckis removed.

Broth is teeming with microorganisms.

Section 1-2

Figure 1-11 Pasteur’s Experiment

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The BOTTOM Line

• In the end science can only explain the natural world

• We use the scientific method to explain the natural world

• We use experiments to observe, interpret, and explain the natural world

In class assignment

• READ Ch 1-2 and Ch 1-3• Answer all the questions

– SA 1-2 and SA 1-3

• Turn in to the front basket

• On a separate sheet of paper– After you are done, create an 8 window cartoon

experiment using the scientific method– Color and label

Homework

• Using the steps of the scientific method, finish your cartoon experiment

• Return all books properly

• Study for quiz• Have a good day