When a physicist wants to use particles with low mass to produce
particles with greater mass,
all she has to do is put the low-mass particles into
an accelerator, give them a lot of kinetic energy (speed),
and then collide them
During this collision, the particle's kinetic energy is converted into
the formation of new massive particles.
It is through this process that we can
create massive unstable particles and study their properties.
It is as if you stage a head-on collision between two
strawberries and get several new strawberries,
lots of tiny acorns, a banana, a
few pears, an apple, a walnut, and a plum.