The Physical Sciences

Chapter One: What Physics and Chemistry are About 1.1 The Physical Science in Your Life 1.2 Describing the Physical World 1.3 Energy, Matter, and Change

1.3 The forms energy can take Energy can exist in many forms, such as heat, motion, height, pressure, and electricity.

1.3 The sun is the source of energy for Earth The Sun’s energy drives the entire food chain. Plants use the energy in sunlight to make sugars from carbon dioxide in the air and water from the ground. Plants store the sugar as energy. Animals eat plants or other animals to get energy.

1.3 The sun is the source of energy for Earth Mars is farther from the Sun than Earth and gets less energy. Can life exist on Mars?

1.3 Forces A force is a push or pull, or any action that is able to change motion. Forces can be used to make an object go faster or slower, or turn in a new direction.

1.3 Forces Forces are created in many different ways. Each of these actions can create force and they all can change an object’s motion.

1.3 Forces No matter what creates the force, forces require a source of energy. One simple way to think about energy is as the stored ability to create forces.

1.3 Forces Imagine stirring a pot of cocoa over a fire. Think about these three changes that happen: 1. The cocoa is moving as you stir it. 2. The cocoa in the pot is getting warmer. 3. The wood in the fire is burning to make heat. What forces are causing these changes?

1.3 Why are atoms so important? Atoms explain all the properties of matter. Before people understood about atoms, the changing of ice to water was a mystery.

1.3 Atoms Ice is solid because the atoms are stuck to each other by their attractive forces.

1.3 Atoms Liquid water flows because its atoms are not stuck as tightly to each other as they are in solid water (ice). What explains why atoms wiggle more in liquids than in solids?

1.3 Matter There are many kinds of matter. The millions of different kinds of matter are all made from different combinations of atoms.

1.3 Atoms and chemistry Just as thousands of words can be made with only 26 letters, all the millions of different kinds of matter are made from about 90 different kinds of atoms.

1.3 Atoms and chemistry The word “water” is spelled with five letters. The water molecule is “spelled” with three atoms: hydrogen-oxygen-hydrogen, or H-O-H, usually written H 2 O.

1.3 Atoms and chemistry We call each kind of atom an element. An element (like gold) is a pure form of matter that cannot be broken down into other elements.

Technology Connection Gas-electric hybrid cars look and drive about like any other car, but use % less gas. How do Hybrid Cars Work?

Activity In this activity you will be using a triple beam balance to measure mass and estimate the masses of everyday objects. Guess the gram