Sean Walker

Sean Walker
Sean Walker is currently finishing his last few years of a PhD program in Computer Science at Stanford University. Sean taught the introductory Computer Graphics class at Stanford for two summers, TA’d more times than he would have liked, and currently moonlights as an SAT instructor and tutor for one of the major SAT prep companies.

Sandy Wagner Ph.D. (Domain Expert)

Sandy Wagner Ph.D. (Domain Expert)
For over 20 years Dr. Wagner taught mathematics, science, computer science, and teacher education from 7th grade through college. His other careers have included software manager, mathematics textbook author, and designer of online classes. Recently he was delighted to return to mathematics, his first true love, and to helping teachers explore ways to improve teaching and learning with technology.

Helen Scully

Helen Scully
Helen Scully was born in 1977 and received her degree from Brown University. She has long been committed to creating quality, imaginative education content. Her novel, In the Hope of Rising Again, was published in 2004.
Author of the chapter(s):

Algebraic Thinking
Using Decimals
Using Fractions

Jim Sconyers

Jim Sconyers
Jim taught secondary math from the East Coast to Hawaii and back to West Virginia. He worked with teachers and students from kindergarten through high school as a math/science specialist. Jim also spent several years creating and managing statewide math testing programs. Along the way Jim published many articles in math and science teacher journals, and he edited secondary math textbooks. Jim has a special interest in hands-on and project-based math learning.
Author of the chapter(s):

Perimeter and Area
Reasoning and Proof
Similarity
Transformations

Geoff Ruth (Domain Expert)

Geoff Ruth (Domain Expert)
Geoff Ruth teaches chemistry, AP Chemistry, geology, and environmental science at the Urban School of San Francisco. Before coming to Urban, he taught science at Leadership High School for five years, and wrote chemistry curriculum at Lawrence Hall of Science. Geoff earned a geology degree from Carleton College, and tries to integrate many different science and math topics into his classes. When not teaching, he enjoys bicycling, rock climbing, woodworking, and exploring the Sierra.

Kurt Rosenkrantz

Kurt Rosenkrantz
Kurt Rosenkrantz is a curriculum specialist at a website specializing in interactive science and math simulations. He spent eight years teaching middle school and high school science in California and New York. He has a bachelor’s degree in Earth Science from Harvard and a master’s degree in Geology from the University of Cincinnati (specializing in invertebrate paleontology). He grew up in Vermont and currently resides in Chapel Hill, North Carolina.
Author of the chapter(s):

Triangles and Vectors

Chell Roberts

Chell Roberts
Chell Roberts is the Chair of a new multidisciplinary engineering program at Arizona State University’s Polytechnic campus. He received a PhD in industrial engineering from Virginia Tech, a master’s degree in industrial engineering from the University of Utah and a bachelor’s degree in mathematics from the University of Utah. Dr. Roberts has published over 70 technical articles, participated in over $2 million dollars of research, provided consulting services to many companies, and served on many national conference organization committees, national review boards, and technical committees. Dr. Roberts’s primary research and teaching interests are in the area of manufacturing automation, computer simulation, and engineering education.
Author of the chapter(s):

Connecting Science and Mathematics to Engineering
Engineering & Society
Introduction to Engineering Design
Nature of Engineering

Richard Parsons

Richard Parsons (Domain Expert, Author)
Graduated San Jose State University BA – 1967 MA – 1968 Taught chemistry and physics in Santa Clara Unified School District 1967 – 2007.

Author of the chapter(s):

Ions and the Compounds They Form
Writing and Naming Ionic Formulas
Covalent Bonding
Covalent Bonding Extended
The Mathematics of Compounds
The Kinetic-Molecular Theory
The Liquid State
The Solid State
Electrochemistry
Nuclear Chemistry

Erik Ong

Erik Ong
Erik Ong is from the San Francisco Bay Area. He has worked in San Ysidro Middle School on the California-Mexico border for ten years as a school counselor and a teacher of algebra and science. He believes in giving all students access to the teaching standards while building vital social skills as well. He was selected as Teacher of the Year for the San Ysidro School District during the 2007-2008 school year.
Author of the chapter(s):

Analyzing Data
Applying Percents
Earth’s Fresh Water
Earth’s Oceans
Linear Functions and Graphs
Polynomials and Nonlinear Functions
Volcanoes
What Is Earth Science?

Colleen O’Donnell

Colleen O’Donnell
Colleen O’Donnell Oppenzato has worked in the field of educational publishing since 1999, developing mathematics curricula for grades 2-11. Before that, Colleen participated in Teach for America and worked as a teacher of exceptional children at the middle school level. She has also worked as a fifth-grade teacher. She is currently completing a master’s degree in Cognitive Studies in Education at Teachers College, Columbia University.
Author of the chapter(s):

Addition and Subtraction of Fractions
Equations, Inequalities, and Functions
Single-Variable Equations and Inequalities
Using Integers
Using Ratios, Rates, and Proportions