"Presents information on simple machines with a focus on pulleys. Explains what a pulley is, how pulleys work, and includes examples of past and present uses. Intended for third to fifth grade students"--Provided by publisher.
"Presents information on simple machines with a focus on levers. Explains what a lever is, how levers work, and includes examples of past and present uses. Intended for third to fifth grade students"--Provided by publisher.
"Presents information on simple machines with a focus on inclined planes. Explains what an inclined plane is, and includes examples of past and present uses. Intended for third to fifth grade students"--Provided by publisher.
Building Better Robots offers a cutting-edge, comprehensive look at one of science's biggest challenges. Includes a look at the history of the topic, recent breakthroughs, key facts to consider, and questions that remain unanswered.
Explains what it means to balance, and looks at some of the things that balance on a construction site, including a sawhorse, ladder, scissor lift, and others.