wave is a wave that appears to be vibrating in place rather than
moving forward. It is caused by the interaction of two identical
waves moving in opposite directions along the same medium. The
resulting displacements are twice as great as those caused by
a single wave. They do not move along the medium, but seem to
stay at set points along the line.
A wave is
any energy disturbance that travels from one location to another
along a medium. Many materials can serve as mediums. Water is
a common example, but waves may also travel through rope, air
and many other substances. Earthquakes are caused by seismic waves
moving through layers of the planet.
It is important
to note that it is the energy, not the medium, that travels in
a wave. If two people are standing in a gymnasium holding a jump
rope taught between them, one of the people can move the rope
up and down, causing a wave to move through the jump rope. The
rope moves up and down or side to side, but it does not move across
the gym. What is being transported is the energy, not the medium.
wave is formed when energy moves in two directions at once. It
is as though both of the people holding the rope started moving
it up and down at the same time. Energy travels from each end
toward the opposite side. When the energy coming from one side
meets the energy coming from the other side, they interfere with
each other, causing a standing wave.
of a wave is the distance between its highest point and the point
of equilibrium. This highest point is called the antinode. In
most waves, the antinode appears to move along the length of the
medium. With a standing wave, the antinode remains in the same
place, because the interference between energies moving in opposite
directions always occurs at the same point. This is also true
of the nodes, or points of least displacement.
at points where the energy from one side is moving up while the
energy from the other side is moving down. The opposing motions
effectively cancel each other out. By contrast, the antinodes
of a standing wave appear at points where the energy from each
side is moving up or down in the same spot. The energy in this
case is doubled, making the motion more pronounced. Antinodes
are always evenly spaced halfway between nodes.