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When we were researching bridges, we came across
words we didn't understand. We tried to put the
meanings in our own words so other kids could understand them better too.
Arch: a structure bent in the shape of a half circle that
supports or makes a building strong. An arch bridge is a
type of bridge.
Beam: a type of bridge made out of a long, straight piece
of wood,metal, or concrete.
Bedrock: the rock lying under the earth and soil.
Cofferdam: cofferdams are closed-in areas under the
water that are pumped dry so that people can bulid or
work on bridges.
Compress: to push or be pushed against something.
Compression is a force used in building bridges.
Concrete: a gray powder called cement is mixed with
water become paste. It hardens to become concrete, a
material which holds other materials together.
Deck: a flat platform.
Effort: force or strength
Force: force helps keep a bridge in balance. If it doesn't
stay still, it could collapse like the Tacoma Narrows
Bridge.
Girder: a flat beam. Also another name for a beam
bridge.
Load: a heavy weight. Bridges must be able to support
heavy loads.
Motor: a machine that changes electricity into
mechanical power to do work. Motors are used on gears.
Gears are used on all kinds of bridges. On drawbridges, gears make the bridge pivot.
Pier: a block of concrete that supports a bridge.
Pivot: to turn around. A drawbridge pivots so that boats
can go through. The road becomes L-shaped when boats
go through and returns to a straight line to let cars across
Span: the length between two supports or points. A span
is how long a bridge is.
Support: to hold something up. Bridges use supports to
help balance their weight and the weight of the load they
carry. If bridges didn't balance,they would fall down.
Suspension: a type of bridge that hangs free on all sides
except at the point of the support. A suspension bridge
is a modern kind of swing bridge.
Tension: to stretch or being stretched into stiffness.
Tension helps a bridge stay in balance.
Tower: a building whose height is greater than its'
thickness. Moveable bridges have controls located in a
tower.
Weight: how heavy something is. A bridge has to be able
to support its' weight and the weight of the load it carries.
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