This document consists of two chapters from the eBook Understanding Physical Geography: Chapter 3: Matter, Energy and the Universe and Chapter 4: Solar Radiation and the Earth. This eBook was written for students taking introductory Physical Geography taught at a college or university. For the chapters currently available on Google Play presentation slides (Powerpoint and Keynote format) and multiple choice test banks are available for Professors using my eBook in the classroom. Please contact me via email at [email protected] if you would like to have access to these resources. The various chapters of the Google Play version of Understanding Physical Geography are FREE for individual use in a non-classroom environment. This has been done to support life long learning. However, the content of Understanding Physical Geography is NOT FREE for use in college and university courses in countries that have a per capita GDP over $25,000 (US dollars) per year where more than three chapters are being used in the teaching of a course. More specifically, for university and college instructors using this work in such wealthier countries, in a credit-based course where a tuition fee is accessed, students should be instructed to purchase the paid version of this content on Google Play which is organized as one of six Parts (organized chapters). One exception to this request is a situation where a student is experiencing financial hardship. In this case, the student should use the individual chapters which are available from Google Play for free. The cost of these Parts works out to only $0.99 per chapter in USA dollars, a very small fee for my work. When the entire textbook (30 chapters) is finished its cost will be only $29.70 in USA dollars. This is far less expensive than similar textbooks from major academic publishing companies whose eBook are around $50.00 to $90.00. Further, revenue generated from the sale of this academic textbook will provide “the carrot” to entice me to continue working hard creating new and updated content. Thanks in advance to instructors and students who abide by these conditions. IMPORTANT - This Google Play version is best viewed with a computer using Google Chrome, Firefox or Apple Safari browsers.