-
Asked by Vladimir Puking to Adam, Eloise, Iona, Jarrod, Yip on 14 Jun 2016.
-
Iona Strawson answered on 14 Jun 2016:
How did he know what the time was? I have no idea. If I was doing it, I’d find a way of marking the time as accurately as possible. Mid day on a sun dial perhaps, even that would be minutes either way though.
Its a really interesting question. My guess would be the first clock was very inaccurate. Or he was the one who decided how the day should be divided up – 24 hours, 60 mins to an hour, 60 secs to a minute.
Theres a really good book called Alex’s Adventures In Numberland that looks at stuff like this. You should check it out.
-
-
Jarrod Hart answered on 16 Jun 2016:
Another book to add to the list is called ‘Longitude’ and it is all about the most famous clock maker of all – a guy called John Harrison.
You see, there was a real problem 300 years ago that when ships sailed across the Atlantic they could not tell their longitude (that is how far east or west they were).
It was easy to see how far north or south they were by looking at the angle of the north star, but to know how far west (and how soon to expect to reach the west indies) they were stuck.
Of course, we know that with a good watch, you can tell how far west you are by the angle of the sun at midday – it your watch (set in london) says noon and the sun is 15 degrees to the east, then you are at a longitude of 15 degrees west – easy.
Only trouble is, clocks 300 years ago would typically lose minutes a day and needed to be reset (hence why the Greenwich observatory drops a ball on it’s roof every day at noon – to let everyone in London reset their rubbish clocks.
John Harrison invented loads of clever new tricks and made a clock accurate to a few seconds a day – he was a real hero of science and engineering – and he won a big prize for solving this seafaring problem!
Comments