Read and find out about six simple machines—the lever, the wheel and axle, the pulley, the ramp, the wedge, and the screw—in this colorfully illustrated non
From axes to doorstops, wedges are at work all over in our world today. Learn all about them in five easy-to-read chapters. Vibrant, full-color photos, bolded g
"Simple Machines! introduces kids to the concept of mechanical advantage and harnesses kid-power by inviting them to build machines of their own design. This bo