Rain Measurement
by Mike Hutton on 11/12/03 at 13:19:23

I'm trying to figure out how to properly measure rain in a home made rain gauge for a childs science experiment.

If I have a 5" funnel capturing water and storing it in a 2" tube, how many true inches of water would it take to reflect an accurate inch of rainfall.

Re: Rain Measurement
by smacksman on 11/12/03 at 15:37:42

Rain is caught by the top 5" diameter (the funnel is ignored) and 1" of rain can be imagined as sitting solid on top.

Therefore the volume of water is pi*2.5*2.5*1 = 19.6375 cu.in.

That drops into a 2" tube which has a cross section area of pi*1*1 = 3.142 sq.in.

The volume of water drops into the tube so has to be the same - so divide the volume by the c/s area and get the height in the tube to equal the volume -

19.6375/3.142 = 6.25"

Go Back | Archive Index