Back in the early 1980s, there was a caption contest in New Scientist magazine, and one week the picture was of one man seated at a computer while another man stood beside him with his hands outstretched to about 30cm. The winning caption was: "Honestly! It was called a slide rule, and it was about this long!"
When the film Hidden Figures was being made, set in the US space program of the 1960s, it was only after they'd finished filming that they realised that all those engineers and mathematicians would have had slide rules to calculate with.
Browsing the antique market this morning, I was delighted to find a slide rule in one of the boxes.
It cost me 50p, and it will be an excellent prop for my UNIT scientist costume.
I have no idea how to use it properly, of course....