Physical Science and You Chapter One: Studying Physics and Chemistry Chapter Two: Experiments and Variables Chapter Three: Key Concepts in Physical Science

3.1 Mass and the Atomic Theory of Matter 3.2 Temperature and Energy

Investigation 3A What is energy? Energy

3.1 Mass Mass is measured in kilograms (kg). One gram (g) is one-thousandth of a kilogram. How many grams is each item above?

3.1 Measuring Mass For small amounts of mass, the kilogram is too large a unit to be convenient. In the laboratory you will usually measure mass with a balance. The balance displays mass in grams.

3.1 Atoms A single atom is the smallest amount of any element you can have.

3.1 Atoms Carbon atoms are different from sodium, aluminum, or oxygen atoms. They have different masses.

3.1 Elements An element is a pure substance that cannot be broken down into other elements. All of the matter you are ever likely to experience is made from one or more elements in nature.

3.1 Compounds A compound is a substance that is made up of more than one element. Pure elements are rare. Most matter exists in the form of compounds.

3.1 Chemical Changes The properties of matter depend on the arrangement of atoms in a compound. Chemical changes can rearrange atoms into different molecules and compounds. Scaly,brown rust is different from hard, silvery steel. How does one turn into the other?

3.1 How atoms explain solids, liquids and gases Atoms are always moving. When the temperature is low, each atom has very little energy of motion. When the temperature is high, each atom has a lot of energy of motion. Can you tell which picture shows the solid and which shows the gas?

Ecology Connection A wind turbine is almost the opposite of a fan. A fan uses electricity to make wind; the turbine uses wind to make electricity. How is this possible? A Mighty Energizing Wind