SCIENTIFIC MODELS

Introduction to Science

Chapter 3.3

Objectives:1. Explain how models are used to represent the

natural world.

2. Identify three types of scientific models.

3. Describe theories and laws.

Bellringer: To teach cardiopulmonary resuscitation (CPR),

instructors often use a mannequin to model a human upper torso and head.

○ Why do you think CPR is taught with a model instead of a real human?

○ Would the class be as effective if a model were not used?

Types of Models Model

A representation of an object or a system.

1. Physical Models○ look like they thing they

represent.○ For example, the model

flower shown at right can be used to learn the parts of a real flower.

2. Mathematical Models ○ Made up of mathematical equations and data.○ The weather map shown below is a mathematical model.

3. Conceptual Models ○ Systems of ideas or are based on making comparisons

with familiar things to explain an idea. Explains the origin of the universe

Models are just the right size

Often used to represent things that are very small or very large.

Useful for studying cells and particles of matter that are too small to see with the unaided eye.

Also useful for studying objects that are too large to see completelysuch as the Earth or the solar system.

Models build scientific knowledge Often used to help illustrate and explain

scientific theories.Theory

○ Unifying explanation for a broad range of hypotheses and observations that have been supported by testing.

Theories and models can change as new observations are made.

Charles Darwin’s Theory of Evolution

1897 Model of Atom Current Model of Atom

Scientific Laws Formed when a theory and its models correctly

predict the results of many different experiments. Law is defined as:

A summary of many experimental results and observations.

Laws are not the same as theories. Laws tell you only what happens, not why it happens.