[time-nuts] Measuring speed of light or reproducing a metre

[Jim Lux]

On 6/23/13 10:48 PM, DaveH wrote:
> Something a bit similar was first published by Nick Hood in 2007.
>
> Here is a copy:
>
> http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p056.
> shtml
>
> Here is Nick's website:
>
> http://cullaloe.com/
>
> Some people use marshmallows.
>
> Dave
>

the only problem is that you don't have a very accurate measurement of 
the microwave oven frequency and the mode pattern isn't very "sharp". 
So this might get you 1 sig fig. Granted, most folks only use 1 sig fig 
3E8 m/sec, but that's just a happenstance since c happens to be close to 
a round number.

And that gets back to another time-nuts kind of question..

How accurately can you measure length and time?  (in a science demo sort 
of way.. without getting a Rb or GPSDO, etc.)  For most school age kids, 
the sources of time available are fairly lengthy (e.g. 1 second ticks 
from wwv by phone, stopwatches built into iphones, etc.)

Tape measures and meter sticks are readily available.