A wheelbarrow is a wheeled container that divides the weight of the load between a wheel and the user. This makes it possible for the user to move loads that are heavier or more bulky than the user could manage without help. Wheelbarrows are often used in gardens and the construction industry.
Many sources claim that wheelbarrows were invented around 200 B.C. in ancient China, but modern research has shown that wheelbarrows were invented in ancient Greece, about 400 B.C. They were used in farming and mining as well as on construction projects.
The classic wheelbarrow design, with a wheel at one end and a pair of handles on the other, divides the weight of the load, functioning as a kind of lever. If the load can be placed closer to the wheel, it greatly reduces the strain on the user. If the load is placed closer to the handles, the user has to bear almost all the weight.
The ancient Chinese modified the wheelbarrow about 200 B.C. by placing the wheel closer to the center, instead of at one end. This meant that the wheel carried almost all the weight, and all the user had to do was steer it. Some wheelbarrows were designed to be pushed, while larger versions (particularly those resembling carts, with two wheels) were pulled by the user.
Early wheelbarrows, including the wheels, were made entirely of wood. Modern wheelbarrows are made of metal and plastics, although the handles are still often made of wood. Some wheels are pneumatic, needing air pressure to inflate them, while others are made of solid rubber or plastic.
Sturdy wheelbarrows with steel containers are heavy but durable. Wheelbarrows and small two-wheeled carts made almost entirely from plastics are much lighter.
Wheelbarrows with a single wheel are very easy to maneuver, and can be run up and down ramps. Heavy loads, however, have to be carefully balanced to prevent them tipping over.
One type of wheelbarrow, popular among gardeners, has two large wheels (similar to spoked bicycle wheels) placed on either side near the center of the box-style body. The front is often removable to make loading and unloading easier. Sometimes called garden carts, these wheelbarrows can carry large and heavy loads such as bales of hay or straw, or even a few hundred pounds of compost or soil.