In 1947 during a study of cosmic ray interactions, a product of a proton collision with a nucleus was found to live for much longer time than expected: 10 -10 seconds instead of the expected 10 -23 seconds. This particle was named the lambda particle (?0) and the property which caused it to live so long was dubbed "strangeness" and that name stuck to be the name of one of the quarks from which the lambda particle is constructed. The lambda is a baryon which is made up of three quarks: an up, a down and a strange quark. This photograph is from a liquid hydrogen bubble chamber at Brookhaven National Laboratory. The yellow line at the bottom is an incoming high-energy proton, it collides with a proton at rest in the liquid hydrogen creating a slew of particles. Seven positive pions, a proton, and a positive kaon (shown in red) curve off to the right, while seven negative pions (blue) move to the right. A neutral lambda is also produced which travels upwards undetected and then decays into a proton (yellow) and a negative pion (purple). NB: the green curve at the bottom is due to an electron which has been knocked out of its orbit by the passing proton.