Greg Roza 
Wedges [PDF ebook] 

Wedges are very useful simple machines. Some wedges, such as axes and knives, help us split things apart. Others, such as nails and pins, help us keep things together. Readers discover the science behind wedges in an educational and engaging way. Accessible text is presented alongside detailed photographs, helping readers independently learn fun facts about how wedges work and the ways we use them every day. A graphic organizer and glossary enhance the reading experience, allowing readers to explore essential science concepts in a thorough and enjoyable manner.