There are six simple machines. They are the lever, the wheel and axle, the pulley, the inclined plane, the wedge and the screw. Simple machines make work easier. Two or more of them can make a compound machine. Let's meet them.

A lever is a bar. It turns around a pivot point called the fulcrum. Look at these. A seesaw is a lever. Scissors are a lever too. A wheelbarrow is a lever as well. A crowbar is also a kind of lever.

A ramp is an inclined plane. So are stairs. It makes it easier to move something upward, but the path is longer. Ramps were probably used when the ancient Egyptians built the pyramids. They were used to move large blocks of stone to the top.

A wedge pushes things apart or cuts them. A wedge is made of two inclined planes put back to back. A door stop is a wedge. A knife is a wedge too. Now look at the screw. A screw helps to hold things together. It turns a twisting motion into movement forward or backward. Ask a grown-up to help with sharp or heavy tools.

A pulley is a wheel that a rope goes over. A flag pole uses a pulley to raise the flag. A wheel and axle helps move a load by turning or rolling. A bicycle is a wheel and axle too. Simple machines make work easier.

Words to know

• lever: turning bar
• fulcrum: the pivot point
• wedge: pushes things apart
• compound: made of parts