induction
science
scientific law
scientific theory
chemistry
physical science
physics

1.1	Lesson Review Questions

1.	Define science.

2.	What is induction?

3.	State the contributions of Thales and Aristotle to the evolution of science.

4.	What was the Scientific Revolution?

5.	Use induction to draw a logical conclusion based on Table below.
Freezing Point of Substances
Substance | Temperature at Freezing (°C)
Pure water (1 cup water) | 0
Salt water (1 cup water + 5 grams table salt) | -4
Sugar water (1 cup water + 6 grams sugar) | -5

6.	What observation would require you to revise your conclusion in question 5?

7.	Compare and contrast scientific theories and scientific laws. Give an example of each.

Points to Consider
Most of the scientists mentioned in this lesson are physical scientists.
•	Based on their work, what do you think is the subject matter of physical science?
•	
•	What are some questions that physical scientists might investigate?

1.2	Lesson Review Questions
1.	Define physical science.

2.	What is the focus of chemistry?

3.	Describe an example of a career in physical science.

4.	What practical question might be answered with physics concepts?

5.	Energy is needed to make matter move. Explain how you use energy to ride a bike uphill. What force allows you to coast downhill without peddling?

Points to Consider
Figure above describes several careers in physical science. Other careers in physical science include research scientist and engineer.
•	What do you think research scientists do?

•	How do you think the work of engineers differs from that of research scientists?

1.1	What is Science
Introduction
Understanding the "hows" and "whys" of the world is the goal of science. The term science comes from a Latin word that means "having knowledge." But science is as much about adding to knowledge as it is about having knowledge. Science is a way of thinking as well as a set of facts. Science can be defined as a way of learning about the natural world that is based on evidence and logic.
Thinking Like a Scientist
Are you like the teen in Figure above? Do you ever wonder why things happen? Do you like to find out how things work? If so, then you are already thinking like a scientist. Scientists also wonder how and why things happen. They are curious about the world. To answer their questions, they make many observations. Then they use logic to draw general conclusions.

Induction
Drawing general conclusions from many individual observations is called induction. It is a hallmark of scientific thinking. To understand how induction works, think about this simple example. Assume you know nothing about gravity. In fact, pretend you’ve never even heard of gravity. Perhaps you notice that whenever you let go of an object it falls to the ground. For example, you drop a book, and it crashes to the floor. Your pencil rolls to the edge of the desk and down it goes. You throw a ball into the air, and it falls back down. Based on many such observations (Figurebelow), you conclude that all objects fall to the ground.

Now assume that someone gives you your first-ever helium balloon. You discover that it rises up into the air if you don’t hold on to it. Based on this new observation, do you throw out your first idea about falling objects? No; you decide to observe more helium balloons and try to find other objects that fall up instead of down. Eventually, you come to a better understanding based on all your observations. You conclude that objects heavier than air fall to the ground but objects lighter than air do not. Your new conclusion is better because it applies to a wider range of observations. You can learn more about induction, including its limits, by watching the video at this link: http://www.youtube.com/watch?v=E1TpZ_HbK3M 

How Science Advances
The above example shows how science generally advances. New evidence is usually used to improve earlier ideas rather than entirely replace them. In this way, scientists gradually refine their ideas and increase our understanding of the world. On the other hand, sometimes science advances in big leaps. This has happened when a scientist came up with a completely new way of looking at things. For example, Albert Einstein came up with a new view of gravity. He said it was really just a dent in the fabric of space and time.

Different conclusions can be drawn from the same observations, and it’s not possible to tell which one is correct. For example, based on observations of the sun moving across the sky, people in the past couldn’t tell whether the sun orbits Earth or Earth orbits the sun. Both models of the solar system are pictured in Figurebelow. It wasn’t until strong telescopes were invented that people could make observations that let them choose the correct idea. Not sure which idea is correct? You can learn more by watching the student-created video at this link:http://www.youtube.com/watch?v=JcqdUq16S28.
Theories and Laws
Some ideas in science gain the status of theories. Scientists use the term "theory" differently than it is used in everyday language. You might say, "I think the dog ate my homework, but it’s just a theory." In other words, it’s just one of many possible explanations for the missing work. However, in science, a theory is much more than that.
Scientific Theories
A scientific theory is a broad explanation that is widely accepted because it is supported by a great deal of evidence. An example is the kinetic theory of matter. According to this theory, all matter consists of tiny particles that are in constant motion. Particles move at different speeds in matter in different states. You can see this in Figure below and at the following URL:http://preparatorychemistry.com/Bishop_KMT_frames.htm. Particles in solids move the least; particles in gases move the most. These differences in particle motion explain why solids, liquids, and gases look and act differently. Think about how ice and water differ, or how water vapor differs from liquid water. The kinetic theory of matter explains the differences. You can learn more about this theory in the chapterStates of Matter.
Scientific Laws
Scientific laws are often confused with scientific theories, but they are not the same thing. A scientific law is a statement describing what always happens under certain conditions in nature. It answers "how" questions but not "why" questions. An example of a scientific law is Newton’s law of gravity. It describes how all objects attract each other. It states that the force of attraction is greater for objects that are closer together or have more mass. However, the law of gravity doesn’t explain why objects attract each other in this way. Einstein’s theory of general relativity explains why. You can learn more about Newton’s law of gravity and Einstein’s theory in the chapter Forces, and at the following link: http://www.youtube.com/watch?v=O-p8yZYxNGc.

Lesson Summary
•	Science is a way of learning about the natural world that is based on evidence and logic. The hallmark of scientific thinking is induction.
•	A scientific theory is a broad explanation that is widely accepted because it is supported by a great deal of evidence. A scientific law is a statement describing what always happens under certain conditions in nature.
•	Modern science has roots that go back thousands of years. Diverse people from around the world have contributed to the evolution of science.
•	Women and minorities have rarely had the same chances in science as white males, but they still have made important contributions.

1.2 The Scope of Physical Science
Introduction
Physical science covers a lot of territory. It’s easier to describe by what it is not than by what it is. Basically, it’s all science that is not life science.
Defining Physical Science
Physical science can be defined as the study of matter and energy. Matter refers to all the "stuff" that exists in the universe. It includes everything you can see and many things that you cannot see, including the air around you. Energy is what gives matter the ability to move and change. Energy can take many forms, such as electricity, heat, and light. Physical science can be divided into chemistry and physics. Chemistry focuses on matter and energy at the scale of atoms and molecules. Physics focuses on matter and energy at all scales, from atoms to outer space.

Chemistry
Chemistry is the study of the structure, properties, and interactions of matter. Important concepts in chemistry include physical changes, such as water freezing, and chemical reactions, such as fireworks exploding. Chemistry concepts can answer all the questions on the left page of the notebook in Figure below. Do you know the answers?

Physics
Physics is the study of energy and how it interacts with matter. Important concepts in physics include motion, forces such as magnetism and gravity, and different forms of energy. 
Physical Science and You
Physical science explains much of what you observe and do in your daily life. In fact, you depend on physical science for almost everything that makes modern life possible. You couldn’t drive a car, text message, or send a tweet without decades of advances in chemistry and physics. You wouldn’t even be able to turn on a light.Figure below shows some other examples of common activities that depend on advances in physical science. You’ll learn the "hows" and "whys" about them as you read the rest of this book.
Careers in Physical Science
People with training in physical science are employed in a variety of places. There are many career options. Just four are described in Figure below. Many more are described at the URL below. Do any of these careers interest you?
Lesson Summary
•	Physical science is the study of matter and energy. It includes chemistry, which focuses on matter, and physics, which focuses on energy.
•	Physical science explains everyday observations and actions. Its advances make modern life possible.
•	There are many career options in physical science. Examples include pharmacist and surveyor.