One way of making observations

Graphic - tippytop
Credit http://www.fysik.lu.se/gemensam/bilddatabasen/historic/slides/library
Obervations can be casual, springing simply from curiosity about what you see in the world around you. The picture shows Wolfgang Pauli (left) and Nils Bohr –two of the fathers of quantum physics– crouched over a ‘tippy’ top.