By accelerating
particles to very high energies and smashing them into targets,
or into each other physicists can unravel the forces acting between
them.
Accelerators come in two types, linear (see the LINAC)
and circular. Accelerators use powerful electric fields to push
energy into a beam of particles - causing an increase in velocity
and kinetic energy. Magnetic fields are used to keep the beam
tightly focused, and in circular machines to steer the particles
around the ring. See the cyclotron
and the synchrotron.
Linear machines
push energy into the beam all along the accelerator's length.
The longer the machine, the higher the final energy, but this
has practical implications!
In
circular machines the particles go round and round again, collecting
energy with each lap. But the faster the particles are going,
the more they try to 'skid' off the ring, just like cars going
round a tight curve in the road. CERN's biggest accelerator, the
Large Electron Positron collider LEP, is 27 kilometres round,
keeping the curves as gentle as possible.
In
circular machines the particles go round and round again, collecting
energy with each lap. But the faster the particles are going,
the more they try to 'skid' off the ring, just like cars going
round a tight curve in the road. CERN's biggest accelerator, the
Large Electron Positron collider LEP, is 27 kilometres round,
keeping the curves as gentle as possible. 
