The Process

Of Science

1. Make observations about the world in which you live.

2. Ask questions that can be studied further.

Hypothesis #1:Dead batteries

Hypothesis #2:Burnt-out bulb

Observations

Question

3. Questions lead to hypotheses.

Hypothesis #1:Dead batteries

Hypothesis #2:Burnt-out bulb

Test prediction

Test falsifies hypothesis

Prediction:Replacing batterieswill fix problem

Prediction:Replacing bulbwill fix problem

Test prediction

Test does not falsify hypothesis

4. Hypotheses are tested in experiments.

-Independent variable – The variable changed by theperson doing the experiment. ex. Changing thebatteries on the flashlight.

-Dependent Variable – The variable that changes as a resultof the changing of the independent variable. Ex. Theflashlight now turning on.

1. What is the independent variable?

2. Is this a controlled experiment? Why or why not?

3. What is the dependent variable?

Each set of plants received identical treatment except set Breceived more sunlight each day.

1. Is this a controlled experiment? Why or why not?

2. What is the independent variable?

3. What is the dependent variable?

4. Why is there more than one plant in each set?

Designing Controlled Experiments

• Scientists do not control the experimental environment by keeping all variables constant

• A controlled experiment only tests a single variable at a time.

• Researchers usually “control” unwanted variables by using control groups to cancel their effects

5. Results from the experiment(s) are analyzed.

6. Conclusions are made based on the results from theexperiment.

Theories in Science

• A scientific theory is:

– broad in scope

– general enough to generate new hypotheses

– supported by a large body of evidence

Model Building in Science

• Models are representations of ideas, structures, or processes

• Models may range from lifelike representations to symbolic schematics From

bodyFromlungs

Rightatrium

Leftatrium

Rightventricle

Leftventricle

To lungs To body

A CASE STUDY

A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations

-In mimicry, a harmless species resembles a harmful species.

-An example of mimicry is a stinging honeybee and a nonstinging mimic, a flower fly.

Flower fly (nonstinging)

Honeybee (stinging)

•This case study examines king snakes’ mimicry

of poisonous coral snakes.

•The hypothesis states that mimics benefit when

predators mistake them for harmful species.

•The mimicry hypothesis predicts that predators in

non–coral snake areas will attack king snakes more

frequently than will predators that live where

coral snakes are present.

Scarlet king snake

Eastern coralsnake

Scarlet king snake

Key

Range of scarlet king snake

NorthCarolina

Range of easterncoral snake

SouthCarolina

•To test this mimicry hypothesis,

researchers made hundreds of artificial snakes:

–An experimental group resembling king snakes

–A control group resembling plain brown snakes

•Equal numbers of both types were placed at field sites,

including areas without coral snakes.

•After four weeks, the scientists retrieved the artificial

snakes and counted bite or claw marks.

The data fit the predictions of the mimicry hypothesis.

(a) Artificial king snake

(b) Artificial brown snake that has been attacked

In areas where coral snakes were present, most attacks were on brown artificial snakes.

In areas where coral snakeswere absent, most attacks

were on artificial king snakes.

% of attacks onartificial king snakes

% of attacks onbrown artificial snakes

Field site withartificial snakes

83%

NorthCarolina

SouthCarolina

17%

16%

84%

Key

-Was this experiment carried out in a logical method?

-Was the conclusion based on evidence?

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-Does all science follow the “scientific method?

*When red next to yellow, deadly fellow. Red next to black,friend of Jack!