For anyone going on holiday to Florence, I recommend a visit to the Galileo Museum. It used to be known as the Museum of the History of Science, but obviously the Galileo brand was a bigger draw.
It's on the River Arno right beside the Uffizi Gallery, so is very easy to find. Inside are some truly wonderful globes, Galileo's telescopes, a couple of his books, the apparatus he devised to work out the speed of objects falling down an incline, and a quite stunning Jovilabe, used to determine the position of the Medicean moons.
A museum guide can be downloaded by clicking here.