Why are rain gauges so small?

Question

my kids wading pool always has like 10 times as much rain as what the rain gauge said we got.

Answer 1

If you look at the sides you will see they slope down and are wider at the top. Only a container that has the same area on the top and bottom gives the right depth in the gage.

Think of a big funnel that goes down into a soda straw. The funnel is 10 inches in area and collected all the water that fell on those ten square inches. Then the water runs down into a straw that is a quarter-inch square area. That is 1/40th the size of the funnel top so the height of its column will be 40 times higher than it should be.

Answer 2

Your mind might be playing tricks on you. Is the pool full of water when it rains or is it empty? It just might look like a lot because there is already water in the pool. The rain gauge on the other hand, is a rough estimate of how much rain fell. It should be empty when it starts to rain, and because rain usually is spread equal over the area, the size of the rain gauge doesnt really matter because it fills up cylinders at equal rates.

Answer 3

Well your kid's wading pool has a much larger cross sectional area than a rain gauge does, so it will have less volume

V = pi*r^2*h But the cross section area is pi*r^2 (if its a circle)

So V = A*h

If the Area increases, then the volume it holds will increase. Rain gauges are meant to measure inches, as in height. Not volume of water.

Answer 4

because meterologist study a small parcile of air 1 inch across. thats why you see incriments of a inch. a rain gauge indicates that over one inch of ground has had this much rain. your kids pool has a large surface area. and so if it is 9ft long that is a lot of water that it has collected.

Answer 5

Its also small to avoid input from the surrounding environment and to stop debris from entering. A small area also has less evaporation.