Sally M Walker

What do a doorstop, a butter knife, and the front of a boat have in common? All of them are wedges! Wedges are simple machines. They help us to do jobs more easily. But don't take our word for it. Put wedges to the test with the fun experiments you'll find in this book. As part of the Searchlight Books collection, this series sheds light on a key science question―How Do Simple Machines Work? Hands-on experiments, interesting photos, and useful diagrams...

In this Early Bird title, readers learn about the physical characteristics, habitat, and behavior of the opossum.

What is matter and where can it be found? Everything in the world is made of matter, whether it is a solid, a liquid, or a gas. Important ideas about matter such as volume, mass, and how matter changes state are conveyed through a series of easy-to-do experiments.

Why do some things heat up quickly while others don't? How can heat cause matter to change form-from solid to liquid to gas and back again? Heat cannot be seen, but it can easily be felt. Looking at different objects' molecular makeup, this book describes the fundamentals of heat and furthers understanding through a series of easy experiments.

Award-winning author Sally M. Walker brings colonial American history to life through the discovery of an important homestead in seventeenth-century Maryland. She follows the painstaking work of scientists and historians to coax fascinating stories out of the long-crumbled walls.

Where does electricity come from? How does it make a computer run or a light bulb shine? Electricity is a form of energy that can be used in many ways. Starting with the tiny particles that make up atoms—electrons, protons, and neutrons—this book highlights the basics of how electricity works and furthers understanding through a series of easy-to-do experiments.

High in the sky, Bessie Coleman could soar like a bird. She was free--at least until she landed. As a black woman in the 1920s, she wasn't allowed to learn how to fly. Forced to travel to France to learn, she became the first African American woman to earn her pilot's license. Whether she was wing-walking, giving a speech, parachuting, or flying, Coleman inspired people with her bravery and resolve.

Why do some things heat up quickly while others don’t? How can heat cause matter to change form—from solid to liquid to gas and back again? Heat cannot be seen, but it can easily be felt. Looking at different objects’ molecular makeup, this book describes the fundamentals of heat and furthers understanding through a series of easy experiments.

110 million years ago, a lush river flowed through the heart of what is now a desert in Africa. Lurking in the depths of the river, a humungous monster waited for its prey to come to the river's edge to drink…and to die. More than 40 feet long, this giant ancestor of the crocodile stalked and killed dinosaurs. In 1997, dinosaur hunter Paul Sereno discovered the enormous reptile fossil named SuperCroc. Learn how modern science uncovers the ancient...

What is matter and where can it be found? Everything in the world is made of matter, whether it is a solid, a liquid, or a gas. Important ideas about matter such as volume, mass, and how matter changes state are conveyed through a series of easy-to-do experiments.