B What can I make to keep track of time without electricity

1. Jan 23, 2016

Michael2525

I need to make a time keeping apparatus that doesn't require electricity. It needs to be something I can make at home and can obtain the resources from a local department store(menards or Home Depot etc.). Any suggestions?

2. Jan 23, 2016

Staff: Mentor

sun clock, Roman water clock or sand clock, Foucault's pendulum

3. Jan 23, 2016

Michael2525

Those clocks are not accurate enough, I need something that can be measured to at least the nearest half second, tenth second preferably.

4. Jan 23, 2016

Staff: Mentor

So you need a traditional watch that can be wound up. The more accurate the more expensive they are.
A wall clock would give you the half second.

5. Jan 23, 2016

Michael2525

Except it has to be handmade. Do you think an oscillating spring or a Newton cradle would work?

6. Jan 23, 2016

Staff Emeritus
That's precision, not accuracy. Accuracy is "loses or gains less than a second per year".

7. Jan 23, 2016

Staff: Mentor

For a while. You can't compensate friction.

8. Jan 23, 2016

Michael2525

Actually, if I had a pendulum attached to something with little friction, wouldn't that work?

It only needs to run for six minutes

9. Jan 23, 2016

Staff: Mentor

I'd try Newton's cradle.

10. Jan 23, 2016

Michael2525

Do you know any special materials that would reduce friction? Would oil help?

11. Jan 23, 2016

Staff: Mentor

It is the air and the bumps that reduces energy. With 2 or 3 heavy metal balls you probably have the least loss.

12. Jan 23, 2016

Staff: Mentor

13. Jan 23, 2016

Staff Emeritus
A) How will you mechanically count swings?
B) How will you get the sub-second precision you say you need?

14. Jan 23, 2016

davenn

exactly, a clock would still be needed to time the swings
you are not going to build something with the accuracy you need that is non-electronic from things at home
So why does it have to be non-electronic ?

15. Jan 24, 2016

Staff: Mentor

Dripping water, fed from a reservoir that is kept full to the brim and overflowing so its timing doesn't "run down". A few drops per second should be manageable.

16. Jan 24, 2016

CWatters

It's not clear what you mean. Do you mean "can be measured" or "can be used to measure" ?

If you are trying to build something that can measure something to a tenth of a second then it may help to tell us what exactly it is you are trying to measure?

17. Jan 24, 2016

Staff: Mentor

Some clock-making schools required their students to make a clock or watch from scratch starting from a block of brass as their final exam. So, yes you can make a top quality mechanical clock at home. You just need a lot of skills and practice.

18. Jan 24, 2016

Staff: Mentor

They can be made even from wood. However, to achieve a measurement of .1 s one needs a lot of skills and really many toothed wheels. Tough job to be done at school. I bet that even Swiss schools never would require such a work to be done by students.

19. Jan 24, 2016

sophiecentaur

Newton's cradle would be less accurate than a single pendulum because of the losses during those collisions and the spread of time periods between the individual pendulums.
A free swinging pendulum without an energy source can be very accurate but, as with real clocks, the pendulum needs to get energy to stop it running down. Foucault's Pendulum would go for, say 24 hours if you could have access to a stair well or very high ceiling (10m+) and a good knife edge mounting to hang it from. Six months running time is a tall order unless you are a pretty good machinst and can make yourself what would be effectively of fully working pendulum clock. Counting the swings involves taking energy from the system unless you use an elecrical detection system.
Let's face it, this is a very tall order. They had enough trouble making accurate clocks when they had access to highly skilled craftsmen and decades of experience.
A good non-electronic time reference, not reliant upon very good mechanisms is Astronomical observations (say the orbits of the moons of Jupiter) that was a serious condender in the quest for Longitude measurements by navigators. But you can't buy a good enough telescope from a hardware store. A solar clock (armillary sun dial) can give accuracy of less than a minute if there is a clear view of the Sun and the shadow has a long throw. The shadow moves at half the rate of a clock hour hand and can be calibrated with a regular clock. It's time varies a bit over the year because of the Earth's Orbit but that's easy to calibrate out that variation. You just need to set it up correctly. You need to live somewhere sunny, for reliability. You could, perhaps, make yourself a Backstaff, which was the forerunner of the Sextant. With that, you could make astronomical observations to get the time from stars, the Moon or the Sun.
Why not go back and ask 'them' to set realistic targets for this project or call their bluff and ask how 'they' would do it.

20. Jan 24, 2016

Staff: Mentor

Add dye to the water, then to perform the timing you could have someone (or a mechanism) swiftly draw a ribbon of white paper through the stream to record each drip as an individual coloured spot on the ribbon.