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 batteries will fix problem Prediction: Replacing bulb will fix problem Test prediction Test does not falsify hypothesis 4. Hypotheses are tested in experiments.

-Independent variable – The variable changed by the person doing the experiment. ex. Changing the batteries on the flashlight. -Dependent Variable – The variable that changes as a result of the changing of the independent variable. Ex. The flashlight 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 B received 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 the experiment.

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 body From lungs Right atrium Left atrium Right ventricle Left ventricle 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 coral snake Scarlet king snake Key Range of scarlet king snake North Carolina Range of eastern coral snake South Carolina

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 snakes were absent, most attacks were on artificial king snakes. % of attacks on artificial king snakes % of attacks on brown artificial snakes Field site with artificial snakes 83% North Carolina South Carolina 17% 16% 84% Key

-Was this experiment carried out in a logical method? -Was the conclusion based on evidence? ?????????????????????????????????????????????????????? -Does all science follow the “scientific method? *When red next to yellow, deadly fellow. Red next to black, friend of Jack!