The Scientific Process

Biology Engineering 2Ms. Haut

The Process of Science

The word science is derived from a Latin verb meaning “to know.” Science is a way of knowing. Science developed from people’s

curiosity about themselves and the world around them.

Hypothesis-Driven Science

As a formal process of inquiry, the scientific method consists of a series of steps. The key element of the scientific

method is hypothesis-driven science.

Scientific Method Observations Question Hypothesis

Prediction Experiment Data Conclusion Retest Communicate

Results

Observation You observe something in the material

world, using your senses or machines which are basically extensions of those senses.

AH—Look at this!

Question You ask a question about what you

observe. State the problem or question.

http://upload.wikimedia.org/wikipedia/commons/thumb/9/9c/Surface_Tension_01.jpg/800px-Surface_Tension_01.jpg

Hypothesis A testable statement about your

observation Based on research

You should be able to give reasons for why you chose your hypothesis

If/then… statement

Deductive reasoning is used in testing hypotheses

– If a hypothesis is supported, and we test it, then we can expect a particular outcome

• Case study: flashlight failure

Figure 1.19

Experiment You figure out a way to test whether the

hypothesis is supported. Control group– nothing changed

Experimental group – one variable changed

The outcome must be measurable (quantifiable).

Record and analyze data.

Biologists developed a hypothesis regarding mimicry in snakes. If an animal has certain color patterns, then

it will not be preyed upon.

They tested the hypothesis by making artificial snakes and observing how often they were attacked by predators.

Figure 1.20

Figure 1.21

This is an example of a controlled experiment.

Such an experiment is designed to compare an experimental group with a control group.

Ideally, a control group and an experimental group differ in only one variable.

Constants: variables that remain the same in all groups

Analyze Results You do the experiment

using the method you came up with and record the results.

Create data tables, graphs to represent data

Perform calculations that will determine what results mean (averages, percentages, totals)

Identify possible sources of errors

Table 1. Percent of total attacks on different colored artificial snakes.

Draw Conclusions You state whether

your hypothesis was supported or not and try to explain your results.

Table 1. Percent of total attacks on different colored artificial snakes.

Retest In order to verify the results, experiments

must be retested.

Communicate Results

Share results with science community

The Culture of Science

Scientists build on what has been learned from earlier research.

They pay close attention to contemporary scientists working on the same problem.

Both cooperation and competition characterize the scientific culture.

Scientists check the conclusions of others by attempting to repeat experiments.

Figure 1.22

Evolution Connection: Theories in Science

What is a scientific theory, and how is it different from a hypothesis?

A theory is much broader in scope than a hypothesis.

Theories only become widely accepted in science if they are supported by an accumulation of extensive and varied evidence.