In the second article in the series, I will describe how theyoung Karl von Frisch, later to become another founding fatherof ethology and Nobel Laureate, defied established authorityto design simple yet logically clever experiments toshow that honey bees indeed have colour vision. His experimentsforever changed our view of animals and also the wayexperiments in animal behaviour are designed. It might interestreaders to know that Karl von Frisch’s experimentsdescribed in this part inspired Tinbergen’s experiments describedin the previous article in this series.