Simple Machines

How many simple machines do you use every day? Probably more than you realize!
 
Machines make work easier— helping break things apart, lift heavy objects, and change the power and direction of force applied to them. In this accessible picture book, celebrated nonfiction author David A. Adler outlines different types of simple machines—wedges, wheels, levers, pulleys, and more—and gives common examples of how we use them every day.
 
Anna Raff's bright illustrations show how simple machines work—and add a dose of fun and humor, too. Two appealing kids and their comical cat use machines to ride see-saws, turn knobs, and even eat apples. 
 
Perfect for classrooms or for budding engineers to read on their own, Simple Machines uses clear, simple language to introduce important mechanical vocabulary, and easy-to-understand examples to illustrate how we use machines to solve all kinds of problems.
 
Don't miss David A. Adler and Anna Raff's other science collaborations—including Light Waves; Magnets Push, Magnets Pull; and Things That Float and Things That Don't.

Standard and Primary covers are widely available through general retailers. They often have higher print runs and can be cheaper, especially during sales.

In contrast, Direct Market (DM) and variant covers are primarily sold in comic shops. DM editions tend to have more limited availability and may be more valuable to collectors.

The main differences lie in artwork style, availability, price, and collector appeal. Ultimately, the choice between standard and variant covers depends on personal preference, budget, and individual collecting goals.

Comic book enthusiasts have various formats to choose from when collecting their favorite stories.
Here's a brief overview of the main types:

Omnibus

• Large, hardcover collections
• Usually contain complete runs or extensive story arcs
• Typically 800-1000+ pages
• Higher price point, often €100-€150

Oversized Hardcover (OHC)

• Similar dimensions to omnibus, but thinner
• Collect shorter runs or story arcs
• Usually 300-600 pages
• Priced between €30-€50

Hardcover (HC)

• Standard-sized hardcover books
• Collect 6-12 issues typically
• Similar dimensions to single issues, but with a hard cover
• Priced around €25-€35

Trade Paperback (TP)

• Softcover collections
• Standard comic book size
• Usually collect 4-6 issues
• Most affordable option, typically €15-€25

Other Formats

• Absolute Editions: Oversized, deluxe hardcovers (mainly DC Comics)
• Compendiums: Massive paperback collections
• Graphic Novels (OGN/GN): Original stories not previously released as single issues

The choice between these formats often depends on personal preference, budget, and collecting goals. Omnibus and OHC editions offer larger artwork and more content but at a higher price, while TPs provide a more affordable way to collect complete story arcs