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# How is Science Made? - PowerPoint PPT Presentation

Scientific Method. How is Science Made?. Observation. 1. Observation : See that there is a problem. -Most students recognized that there was a big stain on my shirt -Make sure there is only one problem being studied!!!. Research the Problem. Look up everything you can on your topic

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Presentation Transcript

Scientific Method

Observation
• 1.Observation: See that there is a problem.
• -Most students recognized that there was a big stain on my shirt
• -Make sure there is only one problem being studied!!!
Research the Problem
• Look up everything you can on your topic
• Visit your library or go on the internet
• Conduct personal interviews
• Search for articles (magazines, journals, books, newspapers) that have been written about the topic you are interested in
Hypothesis
• 2.Hypothesis: an educated guess
• -Typically written as an “if and then” statement
• -“If’ =hypothesis
• -“Then” = results received after the controlled experiment.
Example of “if” “then” hypothesis
• "If a plant receives fertilizer, then it will grow to be bigger than a plant that does not receive fertilizer.”
**It involves a prediction, which explains the problem.
• Ex. of a prediction:The spot on Mrs. Gates shirt is oil
• Then use that prediction to make a hypothesis.
• Ex: If the spot on Mrs. Gates shirt is oil, then the spot should look and smell like oil.
Ex: compare the smell on my shirt to regular oil. Dump oil on an identical shirt and see if the spots look similar. Also put ink, paint, and dirt on the same shirt and compare those spots to the “mystery spot.”
An experiment must have a controlled variable and a manipulated variable
• Control: Serves as a standard for comparison. The control must remain the same throughout the experiment. Ex: the shirt that I am wearing will be the control.
• Variable: A variable that is being changed in the experiment. Ex: the spots of ink, paint, dirt, and oil are the variables in this experiment.
Qualitative vs. Quantitative Data

Quantitative

-Data that uses numbers

-(Height- John is 6’2” Weight- 195 lbs )

Qualitative

-Descriptive, no numbers

-Involves characteristics that

can’t be measured

-Ex. Study of how

gorillas behave

Components of a controlled experiment

A. Control setup

Setup in which all conditions are kept the same

B. Experimental setup

Setup in which all conditions are kept the same except for the one being tested

C. Independent variable

The condition (variable) being changed by you

D. Dependent variable

The condition (variable) being observed or measuredin the experiment

Problem: Does the level of iron in a mouse’s diet affect the number of its red blood cells?

A. Control setup

Normal mouse feed (what is normally fed to the mouse everyday)

B. Experimental setup

Mouse fed different levels of iron in the feed

C. Independent variable

Different amounts of iron added/subtracted from the feed

D. Dependent variable

Number of red bloodcells

Record Results
• 4. Record results: Scientists must keep accurate records of data and observations.
• Ex: write down the differences and similarities of the different spots.
Analyze Results
• 5. Analyze results: Make sense of the data.
• Ex: which spots smelled and looked more similar to the “mystery spot.”
Conclusion
• 6. Make a conclusion: Was your hypothesis supported or proven false. You cannot “prove” a hypothesis after just one experiment. It is not correct to say that the hypothesis was proven correct.
• It is correct to say that the data supports my hypothesis.
Scientific Method Flowchart

Observation

Hypothesis

Experiment

Record Results

Analyze Results

Conclusion

Redi’s Experiment on Spontaneous generation
• Spontaneous generation: About 400 years ago, scientists believed that life arose from non-living matter. Ex: the spot of oil on my shirt will spontaneously turn into a bird!!!
• People once thought that meat magically transforms into flies.
• Francesco Redi (1668) designed a controlled experiment to try and prove this idea false.
• Needham and Spallanzani’s experiments
• Needham was not convinced that spontaneous generation did not exist!!!
Redi’s Experiment on Spontaneous Generation

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

HYPOTHESIS: Flies produce maggots.

PROCEDURE

Covered jars

Uncovered jars

Controlled Variables:

jars, type of meat,

location, temperature,

time

Several

days pass

Manipulated Variables:

gauze covering that

keeps flies away from

meat

Responding Variable:

whether maggots

appear

Maggots appear

No maggots appear

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

Spallanzani’s Experiment

open.

Gravy is teeming

with microorganisms.

Gravy is boiled.

sealed.

Gravy is free of

microorganisms.

Gravy is boiled.

Observation vs. Inference
• Observation:

-Interpretation using one or more of the senses.

Ex: That object is big, green, soft, and heavy

• Inference:

-Is an interpretation based on ones prior knowledge and/or experience.

Ex: The sun makes that tree grow tall .

Observation or Inference?

Statement Observation Inference

Object A is round and orange.

X

X

Object C is round and black and white.

X

Object C is larger than Object B.

X

Object B is smooth.

X

X

Object B is a table-tennis ball.

Each object is used in a different sport.

X