Chapter 1 Section 3 Scientific Models Bellringer To

Chapter 1 Section 3 Scientific Models 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? Explain your answer. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models Objectives • Explain how models are used to represent the natural world. • Identify three types of scientific models. • Describe theories and laws. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models Types of Scientific Models • A representation of an object or a system is called a model. • 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. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models • Demonstrate both a solar eclipse and a lunar eclipse using a large ball, a small ball and flashlight. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models Types of Scientific Models, continued • Mathematical Models are made up of mathematical equations and data. The weather map shown below is a mathematical model. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models Types of Scientific Models, continued • Conceptual Models are systems of ideas or are based on making comparisons with familiar things to explain an idea. • The big bang theory explains the origin of the universe. This theory is an example of a conceptual model. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

CONCEPTUAL MODEL OF AN ATOM Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models • The model of the atom has changed many times. • Atoms were once imagined as tiny balls. We can use sour ball candies to represent them. • Later, the atom was imagined to look like a chocolate chip cookie (with negative charges stuck in a positive substance). • In your study of atomic structure you will learn that more models have been proposed. We use edible models to represent them. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models • Oreo cookies can be used to model the phases of the moon. • Scrape (or eat) the cream from the middle of each cookie. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models Are Just the Right Size • Models are often used to represent things that are very small or very large. • Models are useful for studying cells and particles of matter that are too small to see with the unaided eye. • Models are also useful for studying objects that are too large to see completely, such as the Earth or the solar system. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models Build Scientific Knowledge • Models are often used to help illustrate and explain scientific theories. • In science, a theory is a 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. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

A theory is an explanation for many hypotheses and observations. A theory explains an observation you have made and can predict what might happen in the future. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 1 Section 3 Scientific Models Build Scientific Knowledge, continued • Scientific Laws When a theory and its models correctly predict the results of many different experiments, a scientific law could be formed. • In science, a law is a summary of many experimental results and observations. A law tells you how things work. • Laws are not the same as theories. Laws tell you only what happens, not why it happens. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.