Chapter Three: The Scientific Process

3.1 Inquiry and the Scientific

Method

3.2 Experiments and Variables

3.3 The Nature of Science and

Technology

Section 3.2 Learning Goals

Define experiment.

Contrast experimental and control

variables.

Discuss how experiments are carried

out and the importance of

communicating results.

Investigation 3B

Key Question:

How do you design

a valid

experiment?

Experiments and Variables

3.2 Experiments and variables An experiment is a situation specifically set up to

investigate something and is generally used to

test a hypothesis.

The goal of any experiment is to understand the

relationship between variables.

A variable is a factor that affects how an

experiment works.

In a simple ideal experiment only one variable is

changed at a time.

The variable you change in an experiment

is called the experimental variable (also

called the independent variable).

The variables you keep the same are called

control variables.

Each time you run the experiment is called

a trial.

The variable that changes because of what

you did to the experimental variable is

called the responding variable (also

known as the dependent variable).

Control

variable

Control

variable

Control

variable

Experimental

variable

Trials

3.2 Experimental techniques Your experimental

technique is how you

actually do the

experiment.

The procedure is the

directions that tell you

exactly how to do the

experiment step by

step.

3.2 Experiments then and now

Michael Faraday, a

British scientist,

made some

important

discoveries while

experimenting with

electricity and

magnets.

Faraday’s original

question was “How

are electricity and

magnetism related?”

Electric current is created

when a coil rotates in a

magnetic field.

3.2 Experiments then and now

Earth is like a giant

magnet.

In 1996, NASA

conducted a modern

version of Faraday’s

electromagnetism

experiments using

a tethered satellite.

3.3 The Nature of Science and Technology

Truthful reporting is the most important

tradition of science.

Scientists often write a report of their

experiments and submit it to a scientific

journal.

3.3 The Nature of Science and Technology

Technology is the

application of science

to meet human needs

and solve problems.

Technology arises

from a need for things

to be done better.

3.3 Science and Technology People who design technology to solve

problems are called engineers.

3.3 The Nature of Science and Technology The engineering cycle consists of:

1. designing a prototype

2. building a prototype,

3. testing a prototype, and

4. evaluating a prototype.

The best inventions go through

the cycle many times, being

improved each cycle until all the

problems are worked out.