On Monday a yellow bulldozer pulled into our playground.  There are a lot of parts on the bulldozer.  It has tracks, wheels with teeth, a windshield, hydraulic arms, a cab, a ripper tool and a blade.  We learned that bulldozers can be used to rip out concrete.  First, the bulldozer uses the ripper tool which is 3 long prongs, at the back of the bulldozer, to crack the concrete.  We got to see the broken concrete with metal bars sticking out of it.  The metal bars are called rebar.  Rebar is meant for holding the concrete together to make it stronger.  The bulldozer carried away the broken concrete.  It was a really noisy and exciting day!