Facts101 is your complete guide to Holt Science Spectrum Physical Science with Earth and Space Science. In this book, you will learn topics such as States of Matter, Atoms, The Periodic Table, and The Structure of Matter plus much more. With key features such as key terms, people and places, Facts101 gives you all the information you need to prepare for your next exam. Our practice tests are specific to the textbook and we have designed tools to make the most of your limited study time.