Topic – Construction Machines: Bulldozers and Cranes

Construction Machines: Bulldozers and Cranes

Crane

Bulldozer

Bulldozers

Bulldozers are machines for moving dirt and rocks. Some bulldozers use wheels to move, but most use tracks instead. A track is like a loop of ribbon made from steel. There is a track on each side of a bulldozer. When the tracks turn, the bulldozer moves across the ground. Tracks are good for moving across soft, muddy ground. Wheels can get stuck in muddy ground.

The front of a bulldozer has a part called a blade. The blade pushes dirt or rocks. Some bulldozers have a blade shaped like a scoop. This kind of blade can dig shallow holes and pick up heavy rocks. The blade is attached to two arms that can move the blade up or down.

Cranes

Cranes are powerful machines used to lift heavy objects. Cranes are tall so they can lift objects to high places. Some cranes are on trucks so they can move from place to place. A truck crane can use wheels or tracks to move.

The long arm of a crane has a hook attached to a cable. The cable is like a thick rope made of metal. The hook picks up a heavy object. Then, the crane’s arm moves up to lift the object.

Some cranes are not on trucks. Workers build the crane at a construction site. When the construction is finished, workers take the crane apart and move it away. They will use the crane again at their next construction job.

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